mirror of
https://github.com/c64scene-ar/llvm-6502.git
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165402 91177308-0d34-0410-b5e6-96231b3b80d8
2953 lines
112 KiB
C++
2953 lines
112 KiB
C++
//===- InstructionSimplify.cpp - Fold instruction operands ----------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements routines for folding instructions into simpler forms
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// that do not require creating new instructions. This does constant folding
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// ("add i32 1, 1" -> "2") but can also handle non-constant operands, either
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// returning a constant ("and i32 %x, 0" -> "0") or an already existing value
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// ("and i32 %x, %x" -> "%x"). All operands are assumed to have already been
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// simplified: This is usually true and assuming it simplifies the logic (if
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// they have not been simplified then results are correct but maybe suboptimal).
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "instsimplify"
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#include "llvm/GlobalAlias.h"
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#include "llvm/Operator.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/ADT/SetVector.h"
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#include "llvm/Analysis/InstructionSimplify.h"
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#include "llvm/Analysis/AliasAnalysis.h"
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#include "llvm/Analysis/ConstantFolding.h"
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#include "llvm/Analysis/Dominators.h"
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#include "llvm/Analysis/ValueTracking.h"
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#include "llvm/Support/ConstantRange.h"
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#include "llvm/Support/GetElementPtrTypeIterator.h"
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#include "llvm/Support/PatternMatch.h"
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#include "llvm/Support/ValueHandle.h"
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#include "llvm/DataLayout.h"
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using namespace llvm;
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using namespace llvm::PatternMatch;
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enum { RecursionLimit = 3 };
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STATISTIC(NumExpand, "Number of expansions");
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STATISTIC(NumFactor , "Number of factorizations");
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STATISTIC(NumReassoc, "Number of reassociations");
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struct Query {
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const DataLayout *TD;
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const TargetLibraryInfo *TLI;
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const DominatorTree *DT;
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Query(const DataLayout *td, const TargetLibraryInfo *tli,
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const DominatorTree *dt) : TD(td), TLI(tli), DT(dt) {}
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};
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static Value *SimplifyAndInst(Value *, Value *, const Query &, unsigned);
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static Value *SimplifyBinOp(unsigned, Value *, Value *, const Query &,
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unsigned);
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static Value *SimplifyCmpInst(unsigned, Value *, Value *, const Query &,
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unsigned);
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static Value *SimplifyOrInst(Value *, Value *, const Query &, unsigned);
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static Value *SimplifyXorInst(Value *, Value *, const Query &, unsigned);
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static Value *SimplifyTruncInst(Value *, Type *, const Query &, unsigned);
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/// getFalse - For a boolean type, or a vector of boolean type, return false, or
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/// a vector with every element false, as appropriate for the type.
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static Constant *getFalse(Type *Ty) {
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assert(Ty->getScalarType()->isIntegerTy(1) &&
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"Expected i1 type or a vector of i1!");
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return Constant::getNullValue(Ty);
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}
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/// getTrue - For a boolean type, or a vector of boolean type, return true, or
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/// a vector with every element true, as appropriate for the type.
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static Constant *getTrue(Type *Ty) {
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assert(Ty->getScalarType()->isIntegerTy(1) &&
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"Expected i1 type or a vector of i1!");
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return Constant::getAllOnesValue(Ty);
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}
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/// isSameCompare - Is V equivalent to the comparison "LHS Pred RHS"?
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static bool isSameCompare(Value *V, CmpInst::Predicate Pred, Value *LHS,
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Value *RHS) {
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CmpInst *Cmp = dyn_cast<CmpInst>(V);
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if (!Cmp)
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return false;
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CmpInst::Predicate CPred = Cmp->getPredicate();
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Value *CLHS = Cmp->getOperand(0), *CRHS = Cmp->getOperand(1);
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if (CPred == Pred && CLHS == LHS && CRHS == RHS)
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return true;
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return CPred == CmpInst::getSwappedPredicate(Pred) && CLHS == RHS &&
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CRHS == LHS;
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}
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/// ValueDominatesPHI - Does the given value dominate the specified phi node?
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static bool ValueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) {
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Instruction *I = dyn_cast<Instruction>(V);
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if (!I)
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// Arguments and constants dominate all instructions.
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return true;
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// If we are processing instructions (and/or basic blocks) that have not been
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// fully added to a function, the parent nodes may still be null. Simply
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// return the conservative answer in these cases.
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if (!I->getParent() || !P->getParent() || !I->getParent()->getParent())
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return false;
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// If we have a DominatorTree then do a precise test.
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if (DT) {
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if (!DT->isReachableFromEntry(P->getParent()))
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return true;
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if (!DT->isReachableFromEntry(I->getParent()))
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return false;
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return DT->dominates(I, P);
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}
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// Otherwise, if the instruction is in the entry block, and is not an invoke,
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// then it obviously dominates all phi nodes.
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if (I->getParent() == &I->getParent()->getParent()->getEntryBlock() &&
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!isa<InvokeInst>(I))
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return true;
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return false;
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}
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/// ExpandBinOp - Simplify "A op (B op' C)" by distributing op over op', turning
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/// it into "(A op B) op' (A op C)". Here "op" is given by Opcode and "op'" is
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/// given by OpcodeToExpand, while "A" corresponds to LHS and "B op' C" to RHS.
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/// Also performs the transform "(A op' B) op C" -> "(A op C) op' (B op C)".
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/// Returns the simplified value, or null if no simplification was performed.
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static Value *ExpandBinOp(unsigned Opcode, Value *LHS, Value *RHS,
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unsigned OpcToExpand, const Query &Q,
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unsigned MaxRecurse) {
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Instruction::BinaryOps OpcodeToExpand = (Instruction::BinaryOps)OpcToExpand;
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// Recursion is always used, so bail out at once if we already hit the limit.
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if (!MaxRecurse--)
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return 0;
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// Check whether the expression has the form "(A op' B) op C".
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if (BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS))
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if (Op0->getOpcode() == OpcodeToExpand) {
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// It does! Try turning it into "(A op C) op' (B op C)".
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Value *A = Op0->getOperand(0), *B = Op0->getOperand(1), *C = RHS;
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// Do "A op C" and "B op C" both simplify?
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if (Value *L = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse))
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if (Value *R = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
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// They do! Return "L op' R" if it simplifies or is already available.
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// If "L op' R" equals "A op' B" then "L op' R" is just the LHS.
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if ((L == A && R == B) || (Instruction::isCommutative(OpcodeToExpand)
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&& L == B && R == A)) {
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++NumExpand;
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return LHS;
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}
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// Otherwise return "L op' R" if it simplifies.
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if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
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++NumExpand;
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return V;
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}
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}
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}
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// Check whether the expression has the form "A op (B op' C)".
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if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS))
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if (Op1->getOpcode() == OpcodeToExpand) {
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// It does! Try turning it into "(A op B) op' (A op C)".
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Value *A = LHS, *B = Op1->getOperand(0), *C = Op1->getOperand(1);
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// Do "A op B" and "A op C" both simplify?
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if (Value *L = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse))
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if (Value *R = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse)) {
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// They do! Return "L op' R" if it simplifies or is already available.
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// If "L op' R" equals "B op' C" then "L op' R" is just the RHS.
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if ((L == B && R == C) || (Instruction::isCommutative(OpcodeToExpand)
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&& L == C && R == B)) {
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++NumExpand;
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return RHS;
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}
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// Otherwise return "L op' R" if it simplifies.
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if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) {
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++NumExpand;
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return V;
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}
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}
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}
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return 0;
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}
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/// FactorizeBinOp - Simplify "LHS Opcode RHS" by factorizing out a common term
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/// using the operation OpCodeToExtract. For example, when Opcode is Add and
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/// OpCodeToExtract is Mul then this tries to turn "(A*B)+(A*C)" into "A*(B+C)".
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/// Returns the simplified value, or null if no simplification was performed.
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static Value *FactorizeBinOp(unsigned Opcode, Value *LHS, Value *RHS,
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unsigned OpcToExtract, const Query &Q,
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unsigned MaxRecurse) {
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Instruction::BinaryOps OpcodeToExtract = (Instruction::BinaryOps)OpcToExtract;
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// Recursion is always used, so bail out at once if we already hit the limit.
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if (!MaxRecurse--)
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return 0;
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BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
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BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);
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if (!Op0 || Op0->getOpcode() != OpcodeToExtract ||
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!Op1 || Op1->getOpcode() != OpcodeToExtract)
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return 0;
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// The expression has the form "(A op' B) op (C op' D)".
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Value *A = Op0->getOperand(0), *B = Op0->getOperand(1);
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Value *C = Op1->getOperand(0), *D = Op1->getOperand(1);
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// Use left distributivity, i.e. "X op' (Y op Z) = (X op' Y) op (X op' Z)".
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// Does the instruction have the form "(A op' B) op (A op' D)" or, in the
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// commutative case, "(A op' B) op (C op' A)"?
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if (A == C || (Instruction::isCommutative(OpcodeToExtract) && A == D)) {
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Value *DD = A == C ? D : C;
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// Form "A op' (B op DD)" if it simplifies completely.
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// Does "B op DD" simplify?
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if (Value *V = SimplifyBinOp(Opcode, B, DD, Q, MaxRecurse)) {
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// It does! Return "A op' V" if it simplifies or is already available.
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// If V equals B then "A op' V" is just the LHS. If V equals DD then
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// "A op' V" is just the RHS.
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if (V == B || V == DD) {
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++NumFactor;
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return V == B ? LHS : RHS;
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}
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// Otherwise return "A op' V" if it simplifies.
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if (Value *W = SimplifyBinOp(OpcodeToExtract, A, V, Q, MaxRecurse)) {
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++NumFactor;
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return W;
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}
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}
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}
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// Use right distributivity, i.e. "(X op Y) op' Z = (X op' Z) op (Y op' Z)".
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// Does the instruction have the form "(A op' B) op (C op' B)" or, in the
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// commutative case, "(A op' B) op (B op' D)"?
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if (B == D || (Instruction::isCommutative(OpcodeToExtract) && B == C)) {
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Value *CC = B == D ? C : D;
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// Form "(A op CC) op' B" if it simplifies completely..
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// Does "A op CC" simplify?
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if (Value *V = SimplifyBinOp(Opcode, A, CC, Q, MaxRecurse)) {
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// It does! Return "V op' B" if it simplifies or is already available.
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// If V equals A then "V op' B" is just the LHS. If V equals CC then
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// "V op' B" is just the RHS.
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if (V == A || V == CC) {
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++NumFactor;
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return V == A ? LHS : RHS;
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}
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// Otherwise return "V op' B" if it simplifies.
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if (Value *W = SimplifyBinOp(OpcodeToExtract, V, B, Q, MaxRecurse)) {
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++NumFactor;
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return W;
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}
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}
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}
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return 0;
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}
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/// SimplifyAssociativeBinOp - Generic simplifications for associative binary
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/// operations. Returns the simpler value, or null if none was found.
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static Value *SimplifyAssociativeBinOp(unsigned Opc, Value *LHS, Value *RHS,
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const Query &Q, unsigned MaxRecurse) {
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Instruction::BinaryOps Opcode = (Instruction::BinaryOps)Opc;
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assert(Instruction::isAssociative(Opcode) && "Not an associative operation!");
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// Recursion is always used, so bail out at once if we already hit the limit.
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if (!MaxRecurse--)
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return 0;
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BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
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BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);
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// Transform: "(A op B) op C" ==> "A op (B op C)" if it simplifies completely.
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if (Op0 && Op0->getOpcode() == Opcode) {
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Value *A = Op0->getOperand(0);
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Value *B = Op0->getOperand(1);
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Value *C = RHS;
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// Does "B op C" simplify?
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if (Value *V = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) {
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// It does! Return "A op V" if it simplifies or is already available.
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// If V equals B then "A op V" is just the LHS.
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if (V == B) return LHS;
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// Otherwise return "A op V" if it simplifies.
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if (Value *W = SimplifyBinOp(Opcode, A, V, Q, MaxRecurse)) {
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++NumReassoc;
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return W;
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}
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}
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}
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// Transform: "A op (B op C)" ==> "(A op B) op C" if it simplifies completely.
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if (Op1 && Op1->getOpcode() == Opcode) {
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Value *A = LHS;
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Value *B = Op1->getOperand(0);
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Value *C = Op1->getOperand(1);
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// Does "A op B" simplify?
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if (Value *V = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse)) {
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// It does! Return "V op C" if it simplifies or is already available.
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// If V equals B then "V op C" is just the RHS.
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if (V == B) return RHS;
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// Otherwise return "V op C" if it simplifies.
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if (Value *W = SimplifyBinOp(Opcode, V, C, Q, MaxRecurse)) {
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++NumReassoc;
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return W;
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}
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}
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}
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// The remaining transforms require commutativity as well as associativity.
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if (!Instruction::isCommutative(Opcode))
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return 0;
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// Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely.
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if (Op0 && Op0->getOpcode() == Opcode) {
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Value *A = Op0->getOperand(0);
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Value *B = Op0->getOperand(1);
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Value *C = RHS;
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// Does "C op A" simplify?
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if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
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// It does! Return "V op B" if it simplifies or is already available.
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// If V equals A then "V op B" is just the LHS.
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if (V == A) return LHS;
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// Otherwise return "V op B" if it simplifies.
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if (Value *W = SimplifyBinOp(Opcode, V, B, Q, MaxRecurse)) {
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++NumReassoc;
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return W;
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}
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}
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}
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// Transform: "A op (B op C)" ==> "B op (C op A)" if it simplifies completely.
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if (Op1 && Op1->getOpcode() == Opcode) {
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Value *A = LHS;
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Value *B = Op1->getOperand(0);
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Value *C = Op1->getOperand(1);
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// Does "C op A" simplify?
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if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) {
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// It does! Return "B op V" if it simplifies or is already available.
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// If V equals C then "B op V" is just the RHS.
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if (V == C) return RHS;
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// Otherwise return "B op V" if it simplifies.
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if (Value *W = SimplifyBinOp(Opcode, B, V, Q, MaxRecurse)) {
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++NumReassoc;
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return W;
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}
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}
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}
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return 0;
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}
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/// ThreadBinOpOverSelect - In the case of a binary operation with a select
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/// instruction as an operand, try to simplify the binop by seeing whether
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/// evaluating it on both branches of the select results in the same value.
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/// Returns the common value if so, otherwise returns null.
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static Value *ThreadBinOpOverSelect(unsigned Opcode, Value *LHS, Value *RHS,
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const Query &Q, unsigned MaxRecurse) {
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// Recursion is always used, so bail out at once if we already hit the limit.
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if (!MaxRecurse--)
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return 0;
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SelectInst *SI;
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if (isa<SelectInst>(LHS)) {
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SI = cast<SelectInst>(LHS);
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} else {
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assert(isa<SelectInst>(RHS) && "No select instruction operand!");
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SI = cast<SelectInst>(RHS);
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}
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// Evaluate the BinOp on the true and false branches of the select.
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Value *TV;
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Value *FV;
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if (SI == LHS) {
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TV = SimplifyBinOp(Opcode, SI->getTrueValue(), RHS, Q, MaxRecurse);
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FV = SimplifyBinOp(Opcode, SI->getFalseValue(), RHS, Q, MaxRecurse);
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} else {
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TV = SimplifyBinOp(Opcode, LHS, SI->getTrueValue(), Q, MaxRecurse);
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FV = SimplifyBinOp(Opcode, LHS, SI->getFalseValue(), Q, MaxRecurse);
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}
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// If they simplified to the same value, then return the common value.
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// If they both failed to simplify then return null.
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if (TV == FV)
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return TV;
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// If one branch simplified to undef, return the other one.
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if (TV && isa<UndefValue>(TV))
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return FV;
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if (FV && isa<UndefValue>(FV))
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return TV;
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// If applying the operation did not change the true and false select values,
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// then the result of the binop is the select itself.
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if (TV == SI->getTrueValue() && FV == SI->getFalseValue())
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return SI;
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// If one branch simplified and the other did not, and the simplified
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// value is equal to the unsimplified one, return the simplified value.
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// For example, select (cond, X, X & Z) & Z -> X & Z.
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if ((FV && !TV) || (TV && !FV)) {
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// Check that the simplified value has the form "X op Y" where "op" is the
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// same as the original operation.
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Instruction *Simplified = dyn_cast<Instruction>(FV ? FV : TV);
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if (Simplified && Simplified->getOpcode() == Opcode) {
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// The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS".
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// We already know that "op" is the same as for the simplified value. See
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// if the operands match too. If so, return the simplified value.
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Value *UnsimplifiedBranch = FV ? SI->getTrueValue() : SI->getFalseValue();
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Value *UnsimplifiedLHS = SI == LHS ? UnsimplifiedBranch : LHS;
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Value *UnsimplifiedRHS = SI == LHS ? RHS : UnsimplifiedBranch;
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if (Simplified->getOperand(0) == UnsimplifiedLHS &&
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Simplified->getOperand(1) == UnsimplifiedRHS)
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return Simplified;
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if (Simplified->isCommutative() &&
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Simplified->getOperand(1) == UnsimplifiedLHS &&
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Simplified->getOperand(0) == UnsimplifiedRHS)
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return Simplified;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/// ThreadCmpOverSelect - In the case of a comparison with a select instruction,
|
|
/// try to simplify the comparison by seeing whether both branches of the select
|
|
/// result in the same value. Returns the common value if so, otherwise returns
|
|
/// null.
|
|
static Value *ThreadCmpOverSelect(CmpInst::Predicate Pred, Value *LHS,
|
|
Value *RHS, const Query &Q,
|
|
unsigned MaxRecurse) {
|
|
// Recursion is always used, so bail out at once if we already hit the limit.
|
|
if (!MaxRecurse--)
|
|
return 0;
|
|
|
|
// Make sure the select is on the LHS.
|
|
if (!isa<SelectInst>(LHS)) {
|
|
std::swap(LHS, RHS);
|
|
Pred = CmpInst::getSwappedPredicate(Pred);
|
|
}
|
|
assert(isa<SelectInst>(LHS) && "Not comparing with a select instruction!");
|
|
SelectInst *SI = cast<SelectInst>(LHS);
|
|
Value *Cond = SI->getCondition();
|
|
Value *TV = SI->getTrueValue();
|
|
Value *FV = SI->getFalseValue();
|
|
|
|
// Now that we have "cmp select(Cond, TV, FV), RHS", analyse it.
|
|
// Does "cmp TV, RHS" simplify?
|
|
Value *TCmp = SimplifyCmpInst(Pred, TV, RHS, Q, MaxRecurse);
|
|
if (TCmp == Cond) {
|
|
// It not only simplified, it simplified to the select condition. Replace
|
|
// it with 'true'.
|
|
TCmp = getTrue(Cond->getType());
|
|
} else if (!TCmp) {
|
|
// It didn't simplify. However if "cmp TV, RHS" is equal to the select
|
|
// condition then we can replace it with 'true'. Otherwise give up.
|
|
if (!isSameCompare(Cond, Pred, TV, RHS))
|
|
return 0;
|
|
TCmp = getTrue(Cond->getType());
|
|
}
|
|
|
|
// Does "cmp FV, RHS" simplify?
|
|
Value *FCmp = SimplifyCmpInst(Pred, FV, RHS, Q, MaxRecurse);
|
|
if (FCmp == Cond) {
|
|
// It not only simplified, it simplified to the select condition. Replace
|
|
// it with 'false'.
|
|
FCmp = getFalse(Cond->getType());
|
|
} else if (!FCmp) {
|
|
// It didn't simplify. However if "cmp FV, RHS" is equal to the select
|
|
// condition then we can replace it with 'false'. Otherwise give up.
|
|
if (!isSameCompare(Cond, Pred, FV, RHS))
|
|
return 0;
|
|
FCmp = getFalse(Cond->getType());
|
|
}
|
|
|
|
// If both sides simplified to the same value, then use it as the result of
|
|
// the original comparison.
|
|
if (TCmp == FCmp)
|
|
return TCmp;
|
|
|
|
// The remaining cases only make sense if the select condition has the same
|
|
// type as the result of the comparison, so bail out if this is not so.
|
|
if (Cond->getType()->isVectorTy() != RHS->getType()->isVectorTy())
|
|
return 0;
|
|
// If the false value simplified to false, then the result of the compare
|
|
// is equal to "Cond && TCmp". This also catches the case when the false
|
|
// value simplified to false and the true value to true, returning "Cond".
|
|
if (match(FCmp, m_Zero()))
|
|
if (Value *V = SimplifyAndInst(Cond, TCmp, Q, MaxRecurse))
|
|
return V;
|
|
// If the true value simplified to true, then the result of the compare
|
|
// is equal to "Cond || FCmp".
|
|
if (match(TCmp, m_One()))
|
|
if (Value *V = SimplifyOrInst(Cond, FCmp, Q, MaxRecurse))
|
|
return V;
|
|
// Finally, if the false value simplified to true and the true value to
|
|
// false, then the result of the compare is equal to "!Cond".
|
|
if (match(FCmp, m_One()) && match(TCmp, m_Zero()))
|
|
if (Value *V =
|
|
SimplifyXorInst(Cond, Constant::getAllOnesValue(Cond->getType()),
|
|
Q, MaxRecurse))
|
|
return V;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/// ThreadBinOpOverPHI - In the case of a binary operation with an operand that
|
|
/// is a PHI instruction, try to simplify the binop by seeing whether evaluating
|
|
/// it on the incoming phi values yields the same result for every value. If so
|
|
/// returns the common value, otherwise returns null.
|
|
static Value *ThreadBinOpOverPHI(unsigned Opcode, Value *LHS, Value *RHS,
|
|
const Query &Q, unsigned MaxRecurse) {
|
|
// Recursion is always used, so bail out at once if we already hit the limit.
|
|
if (!MaxRecurse--)
|
|
return 0;
|
|
|
|
PHINode *PI;
|
|
if (isa<PHINode>(LHS)) {
|
|
PI = cast<PHINode>(LHS);
|
|
// Bail out if RHS and the phi may be mutually interdependent due to a loop.
|
|
if (!ValueDominatesPHI(RHS, PI, Q.DT))
|
|
return 0;
|
|
} else {
|
|
assert(isa<PHINode>(RHS) && "No PHI instruction operand!");
|
|
PI = cast<PHINode>(RHS);
|
|
// Bail out if LHS and the phi may be mutually interdependent due to a loop.
|
|
if (!ValueDominatesPHI(LHS, PI, Q.DT))
|
|
return 0;
|
|
}
|
|
|
|
// Evaluate the BinOp on the incoming phi values.
|
|
Value *CommonValue = 0;
|
|
for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
|
|
Value *Incoming = PI->getIncomingValue(i);
|
|
// If the incoming value is the phi node itself, it can safely be skipped.
|
|
if (Incoming == PI) continue;
|
|
Value *V = PI == LHS ?
|
|
SimplifyBinOp(Opcode, Incoming, RHS, Q, MaxRecurse) :
|
|
SimplifyBinOp(Opcode, LHS, Incoming, Q, MaxRecurse);
|
|
// If the operation failed to simplify, or simplified to a different value
|
|
// to previously, then give up.
|
|
if (!V || (CommonValue && V != CommonValue))
|
|
return 0;
|
|
CommonValue = V;
|
|
}
|
|
|
|
return CommonValue;
|
|
}
|
|
|
|
/// ThreadCmpOverPHI - In the case of a comparison with a PHI instruction, try
|
|
/// try to simplify the comparison by seeing whether comparing with all of the
|
|
/// incoming phi values yields the same result every time. If so returns the
|
|
/// common result, otherwise returns null.
|
|
static Value *ThreadCmpOverPHI(CmpInst::Predicate Pred, Value *LHS, Value *RHS,
|
|
const Query &Q, unsigned MaxRecurse) {
|
|
// Recursion is always used, so bail out at once if we already hit the limit.
|
|
if (!MaxRecurse--)
|
|
return 0;
|
|
|
|
// Make sure the phi is on the LHS.
|
|
if (!isa<PHINode>(LHS)) {
|
|
std::swap(LHS, RHS);
|
|
Pred = CmpInst::getSwappedPredicate(Pred);
|
|
}
|
|
assert(isa<PHINode>(LHS) && "Not comparing with a phi instruction!");
|
|
PHINode *PI = cast<PHINode>(LHS);
|
|
|
|
// Bail out if RHS and the phi may be mutually interdependent due to a loop.
|
|
if (!ValueDominatesPHI(RHS, PI, Q.DT))
|
|
return 0;
|
|
|
|
// Evaluate the BinOp on the incoming phi values.
|
|
Value *CommonValue = 0;
|
|
for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
|
|
Value *Incoming = PI->getIncomingValue(i);
|
|
// If the incoming value is the phi node itself, it can safely be skipped.
|
|
if (Incoming == PI) continue;
|
|
Value *V = SimplifyCmpInst(Pred, Incoming, RHS, Q, MaxRecurse);
|
|
// If the operation failed to simplify, or simplified to a different value
|
|
// to previously, then give up.
|
|
if (!V || (CommonValue && V != CommonValue))
|
|
return 0;
|
|
CommonValue = V;
|
|
}
|
|
|
|
return CommonValue;
|
|
}
|
|
|
|
/// SimplifyAddInst - Given operands for an Add, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
|
|
const Query &Q, unsigned MaxRecurse) {
|
|
if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
|
|
if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
|
|
Constant *Ops[] = { CLHS, CRHS };
|
|
return ConstantFoldInstOperands(Instruction::Add, CLHS->getType(), Ops,
|
|
Q.TD, Q.TLI);
|
|
}
|
|
|
|
// Canonicalize the constant to the RHS.
|
|
std::swap(Op0, Op1);
|
|
}
|
|
|
|
// X + undef -> undef
|
|
if (match(Op1, m_Undef()))
|
|
return Op1;
|
|
|
|
// X + 0 -> X
|
|
if (match(Op1, m_Zero()))
|
|
return Op0;
|
|
|
|
// X + (Y - X) -> Y
|
|
// (Y - X) + X -> Y
|
|
// Eg: X + -X -> 0
|
|
Value *Y = 0;
|
|
if (match(Op1, m_Sub(m_Value(Y), m_Specific(Op0))) ||
|
|
match(Op0, m_Sub(m_Value(Y), m_Specific(Op1))))
|
|
return Y;
|
|
|
|
// X + ~X -> -1 since ~X = -X-1
|
|
if (match(Op0, m_Not(m_Specific(Op1))) ||
|
|
match(Op1, m_Not(m_Specific(Op0))))
|
|
return Constant::getAllOnesValue(Op0->getType());
|
|
|
|
/// i1 add -> xor.
|
|
if (MaxRecurse && Op0->getType()->isIntegerTy(1))
|
|
if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
|
|
return V;
|
|
|
|
// Try some generic simplifications for associative operations.
|
|
if (Value *V = SimplifyAssociativeBinOp(Instruction::Add, Op0, Op1, Q,
|
|
MaxRecurse))
|
|
return V;
|
|
|
|
// Mul distributes over Add. Try some generic simplifications based on this.
|
|
if (Value *V = FactorizeBinOp(Instruction::Add, Op0, Op1, Instruction::Mul,
|
|
Q, MaxRecurse))
|
|
return V;
|
|
|
|
// Threading Add over selects and phi nodes is pointless, so don't bother.
|
|
// Threading over the select in "A + select(cond, B, C)" means evaluating
|
|
// "A+B" and "A+C" and seeing if they are equal; but they are equal if and
|
|
// only if B and C are equal. If B and C are equal then (since we assume
|
|
// that operands have already been simplified) "select(cond, B, C)" should
|
|
// have been simplified to the common value of B and C already. Analysing
|
|
// "A+B" and "A+C" thus gains nothing, but costs compile time. Similarly
|
|
// for threading over phi nodes.
|
|
|
|
return 0;
|
|
}
|
|
|
|
Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
|
|
const DataLayout *TD, const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifyAddInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT),
|
|
RecursionLimit);
|
|
}
|
|
|
|
/// \brief Accumulate the constant integer offset a GEP represents.
|
|
///
|
|
/// Given a getelementptr instruction/constantexpr, accumulate the constant
|
|
/// offset from the base pointer into the provided APInt 'Offset'. Returns true
|
|
/// if the GEP has all-constant indices. Returns false if any non-constant
|
|
/// index is encountered leaving the 'Offset' in an undefined state. The
|
|
/// 'Offset' APInt must be the bitwidth of the target's pointer size.
|
|
static bool accumulateGEPOffset(const DataLayout &TD, GEPOperator *GEP,
|
|
APInt &Offset) {
|
|
unsigned IntPtrWidth = TD.getPointerSizeInBits();
|
|
assert(IntPtrWidth == Offset.getBitWidth());
|
|
|
|
gep_type_iterator GTI = gep_type_begin(GEP);
|
|
for (User::op_iterator I = GEP->op_begin() + 1, E = GEP->op_end(); I != E;
|
|
++I, ++GTI) {
|
|
ConstantInt *OpC = dyn_cast<ConstantInt>(*I);
|
|
if (!OpC) return false;
|
|
if (OpC->isZero()) continue;
|
|
|
|
// Handle a struct index, which adds its field offset to the pointer.
|
|
if (StructType *STy = dyn_cast<StructType>(*GTI)) {
|
|
unsigned ElementIdx = OpC->getZExtValue();
|
|
const StructLayout *SL = TD.getStructLayout(STy);
|
|
Offset += APInt(IntPtrWidth, SL->getElementOffset(ElementIdx));
|
|
continue;
|
|
}
|
|
|
|
APInt TypeSize(IntPtrWidth, TD.getTypeAllocSize(GTI.getIndexedType()));
|
|
Offset += OpC->getValue().sextOrTrunc(IntPtrWidth) * TypeSize;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/// \brief Compute the base pointer and cumulative constant offsets for V.
|
|
///
|
|
/// This strips all constant offsets off of V, leaving it the base pointer, and
|
|
/// accumulates the total constant offset applied in the returned constant. It
|
|
/// returns 0 if V is not a pointer, and returns the constant '0' if there are
|
|
/// no constant offsets applied.
|
|
static Constant *stripAndComputeConstantOffsets(const DataLayout &TD,
|
|
Value *&V) {
|
|
if (!V->getType()->isPointerTy())
|
|
return 0;
|
|
|
|
unsigned IntPtrWidth = TD.getPointerSizeInBits();
|
|
APInt Offset = APInt::getNullValue(IntPtrWidth);
|
|
|
|
// Even though we don't look through PHI nodes, we could be called on an
|
|
// instruction in an unreachable block, which may be on a cycle.
|
|
SmallPtrSet<Value *, 4> Visited;
|
|
Visited.insert(V);
|
|
do {
|
|
if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
|
|
if (!GEP->isInBounds() || !accumulateGEPOffset(TD, GEP, Offset))
|
|
break;
|
|
V = GEP->getPointerOperand();
|
|
} else if (Operator::getOpcode(V) == Instruction::BitCast) {
|
|
V = cast<Operator>(V)->getOperand(0);
|
|
} else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
|
|
if (GA->mayBeOverridden())
|
|
break;
|
|
V = GA->getAliasee();
|
|
} else {
|
|
break;
|
|
}
|
|
assert(V->getType()->isPointerTy() && "Unexpected operand type!");
|
|
} while (Visited.insert(V));
|
|
|
|
Type *IntPtrTy = TD.getIntPtrType(V->getContext());
|
|
return ConstantInt::get(IntPtrTy, Offset);
|
|
}
|
|
|
|
/// \brief Compute the constant difference between two pointer values.
|
|
/// If the difference is not a constant, returns zero.
|
|
static Constant *computePointerDifference(const DataLayout &TD,
|
|
Value *LHS, Value *RHS) {
|
|
Constant *LHSOffset = stripAndComputeConstantOffsets(TD, LHS);
|
|
if (!LHSOffset)
|
|
return 0;
|
|
Constant *RHSOffset = stripAndComputeConstantOffsets(TD, RHS);
|
|
if (!RHSOffset)
|
|
return 0;
|
|
|
|
// If LHS and RHS are not related via constant offsets to the same base
|
|
// value, there is nothing we can do here.
|
|
if (LHS != RHS)
|
|
return 0;
|
|
|
|
// Otherwise, the difference of LHS - RHS can be computed as:
|
|
// LHS - RHS
|
|
// = (LHSOffset + Base) - (RHSOffset + Base)
|
|
// = LHSOffset - RHSOffset
|
|
return ConstantExpr::getSub(LHSOffset, RHSOffset);
|
|
}
|
|
|
|
/// SimplifySubInst - Given operands for a Sub, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
|
|
const Query &Q, unsigned MaxRecurse) {
|
|
if (Constant *CLHS = dyn_cast<Constant>(Op0))
|
|
if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
|
|
Constant *Ops[] = { CLHS, CRHS };
|
|
return ConstantFoldInstOperands(Instruction::Sub, CLHS->getType(),
|
|
Ops, Q.TD, Q.TLI);
|
|
}
|
|
|
|
// X - undef -> undef
|
|
// undef - X -> undef
|
|
if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
|
|
return UndefValue::get(Op0->getType());
|
|
|
|
// X - 0 -> X
|
|
if (match(Op1, m_Zero()))
|
|
return Op0;
|
|
|
|
// X - X -> 0
|
|
if (Op0 == Op1)
|
|
return Constant::getNullValue(Op0->getType());
|
|
|
|
// (X*2) - X -> X
|
|
// (X<<1) - X -> X
|
|
Value *X = 0;
|
|
if (match(Op0, m_Mul(m_Specific(Op1), m_ConstantInt<2>())) ||
|
|
match(Op0, m_Shl(m_Specific(Op1), m_One())))
|
|
return Op1;
|
|
|
|
// (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
|
|
// For example, (X + Y) - Y -> X; (Y + X) - Y -> X
|
|
Value *Y = 0, *Z = Op1;
|
|
if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z
|
|
// See if "V === Y - Z" simplifies.
|
|
if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, Q, MaxRecurse-1))
|
|
// It does! Now see if "X + V" simplifies.
|
|
if (Value *W = SimplifyBinOp(Instruction::Add, X, V, Q, MaxRecurse-1)) {
|
|
// It does, we successfully reassociated!
|
|
++NumReassoc;
|
|
return W;
|
|
}
|
|
// See if "V === X - Z" simplifies.
|
|
if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
|
|
// It does! Now see if "Y + V" simplifies.
|
|
if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, Q, MaxRecurse-1)) {
|
|
// It does, we successfully reassociated!
|
|
++NumReassoc;
|
|
return W;
|
|
}
|
|
}
|
|
|
|
// X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies.
|
|
// For example, X - (X + 1) -> -1
|
|
X = Op0;
|
|
if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z)
|
|
// See if "V === X - Y" simplifies.
|
|
if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
|
|
// It does! Now see if "V - Z" simplifies.
|
|
if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, Q, MaxRecurse-1)) {
|
|
// It does, we successfully reassociated!
|
|
++NumReassoc;
|
|
return W;
|
|
}
|
|
// See if "V === X - Z" simplifies.
|
|
if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1))
|
|
// It does! Now see if "V - Y" simplifies.
|
|
if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, Q, MaxRecurse-1)) {
|
|
// It does, we successfully reassociated!
|
|
++NumReassoc;
|
|
return W;
|
|
}
|
|
}
|
|
|
|
// Z - (X - Y) -> (Z - X) + Y if everything simplifies.
|
|
// For example, X - (X - Y) -> Y.
|
|
Z = Op0;
|
|
if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y)
|
|
// See if "V === Z - X" simplifies.
|
|
if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, Q, MaxRecurse-1))
|
|
// It does! Now see if "V + Y" simplifies.
|
|
if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, Q, MaxRecurse-1)) {
|
|
// It does, we successfully reassociated!
|
|
++NumReassoc;
|
|
return W;
|
|
}
|
|
|
|
// trunc(X) - trunc(Y) -> trunc(X - Y) if everything simplifies.
|
|
if (MaxRecurse && match(Op0, m_Trunc(m_Value(X))) &&
|
|
match(Op1, m_Trunc(m_Value(Y))))
|
|
if (X->getType() == Y->getType())
|
|
// See if "V === X - Y" simplifies.
|
|
if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1))
|
|
// It does! Now see if "trunc V" simplifies.
|
|
if (Value *W = SimplifyTruncInst(V, Op0->getType(), Q, MaxRecurse-1))
|
|
// It does, return the simplified "trunc V".
|
|
return W;
|
|
|
|
// Variations on GEP(base, I, ...) - GEP(base, i, ...) -> GEP(null, I-i, ...).
|
|
if (Q.TD && match(Op0, m_PtrToInt(m_Value(X))) &&
|
|
match(Op1, m_PtrToInt(m_Value(Y))))
|
|
if (Constant *Result = computePointerDifference(*Q.TD, X, Y))
|
|
return ConstantExpr::getIntegerCast(Result, Op0->getType(), true);
|
|
|
|
// Mul distributes over Sub. Try some generic simplifications based on this.
|
|
if (Value *V = FactorizeBinOp(Instruction::Sub, Op0, Op1, Instruction::Mul,
|
|
Q, MaxRecurse))
|
|
return V;
|
|
|
|
// i1 sub -> xor.
|
|
if (MaxRecurse && Op0->getType()->isIntegerTy(1))
|
|
if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
|
|
return V;
|
|
|
|
// Threading Sub over selects and phi nodes is pointless, so don't bother.
|
|
// Threading over the select in "A - select(cond, B, C)" means evaluating
|
|
// "A-B" and "A-C" and seeing if they are equal; but they are equal if and
|
|
// only if B and C are equal. If B and C are equal then (since we assume
|
|
// that operands have already been simplified) "select(cond, B, C)" should
|
|
// have been simplified to the common value of B and C already. Analysing
|
|
// "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly
|
|
// for threading over phi nodes.
|
|
|
|
return 0;
|
|
}
|
|
|
|
Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
|
|
const DataLayout *TD, const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifySubInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT),
|
|
RecursionLimit);
|
|
}
|
|
|
|
/// SimplifyMulInst - Given operands for a Mul, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
static Value *SimplifyMulInst(Value *Op0, Value *Op1, const Query &Q,
|
|
unsigned MaxRecurse) {
|
|
if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
|
|
if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
|
|
Constant *Ops[] = { CLHS, CRHS };
|
|
return ConstantFoldInstOperands(Instruction::Mul, CLHS->getType(),
|
|
Ops, Q.TD, Q.TLI);
|
|
}
|
|
|
|
// Canonicalize the constant to the RHS.
|
|
std::swap(Op0, Op1);
|
|
}
|
|
|
|
// X * undef -> 0
|
|
if (match(Op1, m_Undef()))
|
|
return Constant::getNullValue(Op0->getType());
|
|
|
|
// X * 0 -> 0
|
|
if (match(Op1, m_Zero()))
|
|
return Op1;
|
|
|
|
// X * 1 -> X
|
|
if (match(Op1, m_One()))
|
|
return Op0;
|
|
|
|
// (X / Y) * Y -> X if the division is exact.
|
|
Value *X = 0;
|
|
if (match(Op0, m_Exact(m_IDiv(m_Value(X), m_Specific(Op1)))) || // (X / Y) * Y
|
|
match(Op1, m_Exact(m_IDiv(m_Value(X), m_Specific(Op0))))) // Y * (X / Y)
|
|
return X;
|
|
|
|
// i1 mul -> and.
|
|
if (MaxRecurse && Op0->getType()->isIntegerTy(1))
|
|
if (Value *V = SimplifyAndInst(Op0, Op1, Q, MaxRecurse-1))
|
|
return V;
|
|
|
|
// Try some generic simplifications for associative operations.
|
|
if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, Q,
|
|
MaxRecurse))
|
|
return V;
|
|
|
|
// Mul distributes over Add. Try some generic simplifications based on this.
|
|
if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add,
|
|
Q, MaxRecurse))
|
|
return V;
|
|
|
|
// If the operation is with the result of a select instruction, check whether
|
|
// operating on either branch of the select always yields the same value.
|
|
if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
|
|
if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, Q,
|
|
MaxRecurse))
|
|
return V;
|
|
|
|
// If the operation is with the result of a phi instruction, check whether
|
|
// operating on all incoming values of the phi always yields the same value.
|
|
if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
|
|
if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, Q,
|
|
MaxRecurse))
|
|
return V;
|
|
|
|
return 0;
|
|
}
|
|
|
|
Value *llvm::SimplifyMulInst(Value *Op0, Value *Op1, const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifyMulInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
|
|
}
|
|
|
|
/// SimplifyDiv - Given operands for an SDiv or UDiv, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
static Value *SimplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
|
|
const Query &Q, unsigned MaxRecurse) {
|
|
if (Constant *C0 = dyn_cast<Constant>(Op0)) {
|
|
if (Constant *C1 = dyn_cast<Constant>(Op1)) {
|
|
Constant *Ops[] = { C0, C1 };
|
|
return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI);
|
|
}
|
|
}
|
|
|
|
bool isSigned = Opcode == Instruction::SDiv;
|
|
|
|
// X / undef -> undef
|
|
if (match(Op1, m_Undef()))
|
|
return Op1;
|
|
|
|
// undef / X -> 0
|
|
if (match(Op0, m_Undef()))
|
|
return Constant::getNullValue(Op0->getType());
|
|
|
|
// 0 / X -> 0, we don't need to preserve faults!
|
|
if (match(Op0, m_Zero()))
|
|
return Op0;
|
|
|
|
// X / 1 -> X
|
|
if (match(Op1, m_One()))
|
|
return Op0;
|
|
|
|
if (Op0->getType()->isIntegerTy(1))
|
|
// It can't be division by zero, hence it must be division by one.
|
|
return Op0;
|
|
|
|
// X / X -> 1
|
|
if (Op0 == Op1)
|
|
return ConstantInt::get(Op0->getType(), 1);
|
|
|
|
// (X * Y) / Y -> X if the multiplication does not overflow.
|
|
Value *X = 0, *Y = 0;
|
|
if (match(Op0, m_Mul(m_Value(X), m_Value(Y))) && (X == Op1 || Y == Op1)) {
|
|
if (Y != Op1) std::swap(X, Y); // Ensure expression is (X * Y) / Y, Y = Op1
|
|
OverflowingBinaryOperator *Mul = cast<OverflowingBinaryOperator>(Op0);
|
|
// If the Mul knows it does not overflow, then we are good to go.
|
|
if ((isSigned && Mul->hasNoSignedWrap()) ||
|
|
(!isSigned && Mul->hasNoUnsignedWrap()))
|
|
return X;
|
|
// If X has the form X = A / Y then X * Y cannot overflow.
|
|
if (BinaryOperator *Div = dyn_cast<BinaryOperator>(X))
|
|
if (Div->getOpcode() == Opcode && Div->getOperand(1) == Y)
|
|
return X;
|
|
}
|
|
|
|
// (X rem Y) / Y -> 0
|
|
if ((isSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
|
|
(!isSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
|
|
return Constant::getNullValue(Op0->getType());
|
|
|
|
// If the operation is with the result of a select instruction, check whether
|
|
// operating on either branch of the select always yields the same value.
|
|
if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
|
|
if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
|
|
return V;
|
|
|
|
// If the operation is with the result of a phi instruction, check whether
|
|
// operating on all incoming values of the phi always yields the same value.
|
|
if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
|
|
if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
|
|
return V;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/// SimplifySDivInst - Given operands for an SDiv, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
static Value *SimplifySDivInst(Value *Op0, Value *Op1, const Query &Q,
|
|
unsigned MaxRecurse) {
|
|
if (Value *V = SimplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse))
|
|
return V;
|
|
|
|
return 0;
|
|
}
|
|
|
|
Value *llvm::SimplifySDivInst(Value *Op0, Value *Op1, const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifySDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
|
|
}
|
|
|
|
/// SimplifyUDivInst - Given operands for a UDiv, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const Query &Q,
|
|
unsigned MaxRecurse) {
|
|
if (Value *V = SimplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse))
|
|
return V;
|
|
|
|
return 0;
|
|
}
|
|
|
|
Value *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifyUDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
|
|
}
|
|
|
|
static Value *SimplifyFDivInst(Value *Op0, Value *Op1, const Query &Q,
|
|
unsigned) {
|
|
// undef / X -> undef (the undef could be a snan).
|
|
if (match(Op0, m_Undef()))
|
|
return Op0;
|
|
|
|
// X / undef -> undef
|
|
if (match(Op1, m_Undef()))
|
|
return Op1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
Value *llvm::SimplifyFDivInst(Value *Op0, Value *Op1, const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifyFDivInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
|
|
}
|
|
|
|
/// SimplifyRem - Given operands for an SRem or URem, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
static Value *SimplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
|
|
const Query &Q, unsigned MaxRecurse) {
|
|
if (Constant *C0 = dyn_cast<Constant>(Op0)) {
|
|
if (Constant *C1 = dyn_cast<Constant>(Op1)) {
|
|
Constant *Ops[] = { C0, C1 };
|
|
return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI);
|
|
}
|
|
}
|
|
|
|
// X % undef -> undef
|
|
if (match(Op1, m_Undef()))
|
|
return Op1;
|
|
|
|
// undef % X -> 0
|
|
if (match(Op0, m_Undef()))
|
|
return Constant::getNullValue(Op0->getType());
|
|
|
|
// 0 % X -> 0, we don't need to preserve faults!
|
|
if (match(Op0, m_Zero()))
|
|
return Op0;
|
|
|
|
// X % 0 -> undef, we don't need to preserve faults!
|
|
if (match(Op1, m_Zero()))
|
|
return UndefValue::get(Op0->getType());
|
|
|
|
// X % 1 -> 0
|
|
if (match(Op1, m_One()))
|
|
return Constant::getNullValue(Op0->getType());
|
|
|
|
if (Op0->getType()->isIntegerTy(1))
|
|
// It can't be remainder by zero, hence it must be remainder by one.
|
|
return Constant::getNullValue(Op0->getType());
|
|
|
|
// X % X -> 0
|
|
if (Op0 == Op1)
|
|
return Constant::getNullValue(Op0->getType());
|
|
|
|
// If the operation is with the result of a select instruction, check whether
|
|
// operating on either branch of the select always yields the same value.
|
|
if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
|
|
if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
|
|
return V;
|
|
|
|
// If the operation is with the result of a phi instruction, check whether
|
|
// operating on all incoming values of the phi always yields the same value.
|
|
if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
|
|
if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
|
|
return V;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/// SimplifySRemInst - Given operands for an SRem, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
static Value *SimplifySRemInst(Value *Op0, Value *Op1, const Query &Q,
|
|
unsigned MaxRecurse) {
|
|
if (Value *V = SimplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse))
|
|
return V;
|
|
|
|
return 0;
|
|
}
|
|
|
|
Value *llvm::SimplifySRemInst(Value *Op0, Value *Op1, const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifySRemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
|
|
}
|
|
|
|
/// SimplifyURemInst - Given operands for a URem, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
static Value *SimplifyURemInst(Value *Op0, Value *Op1, const Query &Q,
|
|
unsigned MaxRecurse) {
|
|
if (Value *V = SimplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse))
|
|
return V;
|
|
|
|
return 0;
|
|
}
|
|
|
|
Value *llvm::SimplifyURemInst(Value *Op0, Value *Op1, const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifyURemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
|
|
}
|
|
|
|
static Value *SimplifyFRemInst(Value *Op0, Value *Op1, const Query &,
|
|
unsigned) {
|
|
// undef % X -> undef (the undef could be a snan).
|
|
if (match(Op0, m_Undef()))
|
|
return Op0;
|
|
|
|
// X % undef -> undef
|
|
if (match(Op1, m_Undef()))
|
|
return Op1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
Value *llvm::SimplifyFRemInst(Value *Op0, Value *Op1, const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifyFRemInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
|
|
}
|
|
|
|
/// SimplifyShift - Given operands for an Shl, LShr or AShr, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
static Value *SimplifyShift(unsigned Opcode, Value *Op0, Value *Op1,
|
|
const Query &Q, unsigned MaxRecurse) {
|
|
if (Constant *C0 = dyn_cast<Constant>(Op0)) {
|
|
if (Constant *C1 = dyn_cast<Constant>(Op1)) {
|
|
Constant *Ops[] = { C0, C1 };
|
|
return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, Q.TD, Q.TLI);
|
|
}
|
|
}
|
|
|
|
// 0 shift by X -> 0
|
|
if (match(Op0, m_Zero()))
|
|
return Op0;
|
|
|
|
// X shift by 0 -> X
|
|
if (match(Op1, m_Zero()))
|
|
return Op0;
|
|
|
|
// X shift by undef -> undef because it may shift by the bitwidth.
|
|
if (match(Op1, m_Undef()))
|
|
return Op1;
|
|
|
|
// Shifting by the bitwidth or more is undefined.
|
|
if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1))
|
|
if (CI->getValue().getLimitedValue() >=
|
|
Op0->getType()->getScalarSizeInBits())
|
|
return UndefValue::get(Op0->getType());
|
|
|
|
// If the operation is with the result of a select instruction, check whether
|
|
// operating on either branch of the select always yields the same value.
|
|
if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
|
|
if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse))
|
|
return V;
|
|
|
|
// If the operation is with the result of a phi instruction, check whether
|
|
// operating on all incoming values of the phi always yields the same value.
|
|
if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
|
|
if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
|
|
return V;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/// SimplifyShlInst - Given operands for an Shl, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
|
|
const Query &Q, unsigned MaxRecurse) {
|
|
if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse))
|
|
return V;
|
|
|
|
// undef << X -> 0
|
|
if (match(Op0, m_Undef()))
|
|
return Constant::getNullValue(Op0->getType());
|
|
|
|
// (X >> A) << A -> X
|
|
Value *X;
|
|
if (match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
|
|
return X;
|
|
return 0;
|
|
}
|
|
|
|
Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
|
|
const DataLayout *TD, const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Query (TD, TLI, DT),
|
|
RecursionLimit);
|
|
}
|
|
|
|
/// SimplifyLShrInst - Given operands for an LShr, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
|
|
const Query &Q, unsigned MaxRecurse) {
|
|
if (Value *V = SimplifyShift(Instruction::LShr, Op0, Op1, Q, MaxRecurse))
|
|
return V;
|
|
|
|
// undef >>l X -> 0
|
|
if (match(Op0, m_Undef()))
|
|
return Constant::getNullValue(Op0->getType());
|
|
|
|
// (X << A) >> A -> X
|
|
Value *X;
|
|
if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) &&
|
|
cast<OverflowingBinaryOperator>(Op0)->hasNoUnsignedWrap())
|
|
return X;
|
|
|
|
return 0;
|
|
}
|
|
|
|
Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
|
|
const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifyLShrInst(Op0, Op1, isExact, Query (TD, TLI, DT),
|
|
RecursionLimit);
|
|
}
|
|
|
|
/// SimplifyAShrInst - Given operands for an AShr, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
|
|
const Query &Q, unsigned MaxRecurse) {
|
|
if (Value *V = SimplifyShift(Instruction::AShr, Op0, Op1, Q, MaxRecurse))
|
|
return V;
|
|
|
|
// all ones >>a X -> all ones
|
|
if (match(Op0, m_AllOnes()))
|
|
return Op0;
|
|
|
|
// undef >>a X -> all ones
|
|
if (match(Op0, m_Undef()))
|
|
return Constant::getAllOnesValue(Op0->getType());
|
|
|
|
// (X << A) >> A -> X
|
|
Value *X;
|
|
if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) &&
|
|
cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap())
|
|
return X;
|
|
|
|
return 0;
|
|
}
|
|
|
|
Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
|
|
const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifyAShrInst(Op0, Op1, isExact, Query (TD, TLI, DT),
|
|
RecursionLimit);
|
|
}
|
|
|
|
/// SimplifyAndInst - Given operands for an And, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
static Value *SimplifyAndInst(Value *Op0, Value *Op1, const Query &Q,
|
|
unsigned MaxRecurse) {
|
|
if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
|
|
if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
|
|
Constant *Ops[] = { CLHS, CRHS };
|
|
return ConstantFoldInstOperands(Instruction::And, CLHS->getType(),
|
|
Ops, Q.TD, Q.TLI);
|
|
}
|
|
|
|
// Canonicalize the constant to the RHS.
|
|
std::swap(Op0, Op1);
|
|
}
|
|
|
|
// X & undef -> 0
|
|
if (match(Op1, m_Undef()))
|
|
return Constant::getNullValue(Op0->getType());
|
|
|
|
// X & X = X
|
|
if (Op0 == Op1)
|
|
return Op0;
|
|
|
|
// X & 0 = 0
|
|
if (match(Op1, m_Zero()))
|
|
return Op1;
|
|
|
|
// X & -1 = X
|
|
if (match(Op1, m_AllOnes()))
|
|
return Op0;
|
|
|
|
// A & ~A = ~A & A = 0
|
|
if (match(Op0, m_Not(m_Specific(Op1))) ||
|
|
match(Op1, m_Not(m_Specific(Op0))))
|
|
return Constant::getNullValue(Op0->getType());
|
|
|
|
// (A | ?) & A = A
|
|
Value *A = 0, *B = 0;
|
|
if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
|
|
(A == Op1 || B == Op1))
|
|
return Op1;
|
|
|
|
// A & (A | ?) = A
|
|
if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
|
|
(A == Op0 || B == Op0))
|
|
return Op0;
|
|
|
|
// A & (-A) = A if A is a power of two or zero.
|
|
if (match(Op0, m_Neg(m_Specific(Op1))) ||
|
|
match(Op1, m_Neg(m_Specific(Op0)))) {
|
|
if (isPowerOfTwo(Op0, Q.TD, /*OrZero*/true))
|
|
return Op0;
|
|
if (isPowerOfTwo(Op1, Q.TD, /*OrZero*/true))
|
|
return Op1;
|
|
}
|
|
|
|
// Try some generic simplifications for associative operations.
|
|
if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
|
|
MaxRecurse))
|
|
return V;
|
|
|
|
// And distributes over Or. Try some generic simplifications based on this.
|
|
if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or,
|
|
Q, MaxRecurse))
|
|
return V;
|
|
|
|
// And distributes over Xor. Try some generic simplifications based on this.
|
|
if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor,
|
|
Q, MaxRecurse))
|
|
return V;
|
|
|
|
// Or distributes over And. Try some generic simplifications based on this.
|
|
if (Value *V = FactorizeBinOp(Instruction::And, Op0, Op1, Instruction::Or,
|
|
Q, MaxRecurse))
|
|
return V;
|
|
|
|
// If the operation is with the result of a select instruction, check whether
|
|
// operating on either branch of the select always yields the same value.
|
|
if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
|
|
if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q,
|
|
MaxRecurse))
|
|
return V;
|
|
|
|
// If the operation is with the result of a phi instruction, check whether
|
|
// operating on all incoming values of the phi always yields the same value.
|
|
if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
|
|
if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q,
|
|
MaxRecurse))
|
|
return V;
|
|
|
|
return 0;
|
|
}
|
|
|
|
Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifyAndInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
|
|
}
|
|
|
|
/// SimplifyOrInst - Given operands for an Or, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
static Value *SimplifyOrInst(Value *Op0, Value *Op1, const Query &Q,
|
|
unsigned MaxRecurse) {
|
|
if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
|
|
if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
|
|
Constant *Ops[] = { CLHS, CRHS };
|
|
return ConstantFoldInstOperands(Instruction::Or, CLHS->getType(),
|
|
Ops, Q.TD, Q.TLI);
|
|
}
|
|
|
|
// Canonicalize the constant to the RHS.
|
|
std::swap(Op0, Op1);
|
|
}
|
|
|
|
// X | undef -> -1
|
|
if (match(Op1, m_Undef()))
|
|
return Constant::getAllOnesValue(Op0->getType());
|
|
|
|
// X | X = X
|
|
if (Op0 == Op1)
|
|
return Op0;
|
|
|
|
// X | 0 = X
|
|
if (match(Op1, m_Zero()))
|
|
return Op0;
|
|
|
|
// X | -1 = -1
|
|
if (match(Op1, m_AllOnes()))
|
|
return Op1;
|
|
|
|
// A | ~A = ~A | A = -1
|
|
if (match(Op0, m_Not(m_Specific(Op1))) ||
|
|
match(Op1, m_Not(m_Specific(Op0))))
|
|
return Constant::getAllOnesValue(Op0->getType());
|
|
|
|
// (A & ?) | A = A
|
|
Value *A = 0, *B = 0;
|
|
if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
|
|
(A == Op1 || B == Op1))
|
|
return Op1;
|
|
|
|
// A | (A & ?) = A
|
|
if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
|
|
(A == Op0 || B == Op0))
|
|
return Op0;
|
|
|
|
// ~(A & ?) | A = -1
|
|
if (match(Op0, m_Not(m_And(m_Value(A), m_Value(B)))) &&
|
|
(A == Op1 || B == Op1))
|
|
return Constant::getAllOnesValue(Op1->getType());
|
|
|
|
// A | ~(A & ?) = -1
|
|
if (match(Op1, m_Not(m_And(m_Value(A), m_Value(B)))) &&
|
|
(A == Op0 || B == Op0))
|
|
return Constant::getAllOnesValue(Op0->getType());
|
|
|
|
// Try some generic simplifications for associative operations.
|
|
if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q,
|
|
MaxRecurse))
|
|
return V;
|
|
|
|
// Or distributes over And. Try some generic simplifications based on this.
|
|
if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q,
|
|
MaxRecurse))
|
|
return V;
|
|
|
|
// And distributes over Or. Try some generic simplifications based on this.
|
|
if (Value *V = FactorizeBinOp(Instruction::Or, Op0, Op1, Instruction::And,
|
|
Q, MaxRecurse))
|
|
return V;
|
|
|
|
// If the operation is with the result of a select instruction, check whether
|
|
// operating on either branch of the select always yields the same value.
|
|
if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
|
|
if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q,
|
|
MaxRecurse))
|
|
return V;
|
|
|
|
// If the operation is with the result of a phi instruction, check whether
|
|
// operating on all incoming values of the phi always yields the same value.
|
|
if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
|
|
if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
|
|
return V;
|
|
|
|
return 0;
|
|
}
|
|
|
|
Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifyOrInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
|
|
}
|
|
|
|
/// SimplifyXorInst - Given operands for a Xor, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
static Value *SimplifyXorInst(Value *Op0, Value *Op1, const Query &Q,
|
|
unsigned MaxRecurse) {
|
|
if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
|
|
if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
|
|
Constant *Ops[] = { CLHS, CRHS };
|
|
return ConstantFoldInstOperands(Instruction::Xor, CLHS->getType(),
|
|
Ops, Q.TD, Q.TLI);
|
|
}
|
|
|
|
// Canonicalize the constant to the RHS.
|
|
std::swap(Op0, Op1);
|
|
}
|
|
|
|
// A ^ undef -> undef
|
|
if (match(Op1, m_Undef()))
|
|
return Op1;
|
|
|
|
// A ^ 0 = A
|
|
if (match(Op1, m_Zero()))
|
|
return Op0;
|
|
|
|
// A ^ A = 0
|
|
if (Op0 == Op1)
|
|
return Constant::getNullValue(Op0->getType());
|
|
|
|
// A ^ ~A = ~A ^ A = -1
|
|
if (match(Op0, m_Not(m_Specific(Op1))) ||
|
|
match(Op1, m_Not(m_Specific(Op0))))
|
|
return Constant::getAllOnesValue(Op0->getType());
|
|
|
|
// Try some generic simplifications for associative operations.
|
|
if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q,
|
|
MaxRecurse))
|
|
return V;
|
|
|
|
// And distributes over Xor. Try some generic simplifications based on this.
|
|
if (Value *V = FactorizeBinOp(Instruction::Xor, Op0, Op1, Instruction::And,
|
|
Q, MaxRecurse))
|
|
return V;
|
|
|
|
// Threading Xor over selects and phi nodes is pointless, so don't bother.
|
|
// Threading over the select in "A ^ select(cond, B, C)" means evaluating
|
|
// "A^B" and "A^C" and seeing if they are equal; but they are equal if and
|
|
// only if B and C are equal. If B and C are equal then (since we assume
|
|
// that operands have already been simplified) "select(cond, B, C)" should
|
|
// have been simplified to the common value of B and C already. Analysing
|
|
// "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
|
|
// for threading over phi nodes.
|
|
|
|
return 0;
|
|
}
|
|
|
|
Value *llvm::SimplifyXorInst(Value *Op0, Value *Op1, const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifyXorInst(Op0, Op1, Query (TD, TLI, DT), RecursionLimit);
|
|
}
|
|
|
|
static Type *GetCompareTy(Value *Op) {
|
|
return CmpInst::makeCmpResultType(Op->getType());
|
|
}
|
|
|
|
/// ExtractEquivalentCondition - Rummage around inside V looking for something
|
|
/// equivalent to the comparison "LHS Pred RHS". Return such a value if found,
|
|
/// otherwise return null. Helper function for analyzing max/min idioms.
|
|
static Value *ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred,
|
|
Value *LHS, Value *RHS) {
|
|
SelectInst *SI = dyn_cast<SelectInst>(V);
|
|
if (!SI)
|
|
return 0;
|
|
CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
|
|
if (!Cmp)
|
|
return 0;
|
|
Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
|
|
if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
|
|
return Cmp;
|
|
if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
|
|
LHS == CmpRHS && RHS == CmpLHS)
|
|
return Cmp;
|
|
return 0;
|
|
}
|
|
|
|
static Constant *computePointerICmp(const DataLayout &TD,
|
|
CmpInst::Predicate Pred,
|
|
Value *LHS, Value *RHS) {
|
|
// We can only fold certain predicates on pointer comparisons.
|
|
switch (Pred) {
|
|
default:
|
|
return 0;
|
|
|
|
// Equality comaprisons are easy to fold.
|
|
case CmpInst::ICMP_EQ:
|
|
case CmpInst::ICMP_NE:
|
|
break;
|
|
|
|
// We can only handle unsigned relational comparisons because 'inbounds' on
|
|
// a GEP only protects against unsigned wrapping.
|
|
case CmpInst::ICMP_UGT:
|
|
case CmpInst::ICMP_UGE:
|
|
case CmpInst::ICMP_ULT:
|
|
case CmpInst::ICMP_ULE:
|
|
// However, we have to switch them to their signed variants to handle
|
|
// negative indices from the base pointer.
|
|
Pred = ICmpInst::getSignedPredicate(Pred);
|
|
break;
|
|
}
|
|
|
|
Constant *LHSOffset = stripAndComputeConstantOffsets(TD, LHS);
|
|
if (!LHSOffset)
|
|
return 0;
|
|
Constant *RHSOffset = stripAndComputeConstantOffsets(TD, RHS);
|
|
if (!RHSOffset)
|
|
return 0;
|
|
|
|
// If LHS and RHS are not related via constant offsets to the same base
|
|
// value, there is nothing we can do here.
|
|
if (LHS != RHS)
|
|
return 0;
|
|
|
|
return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset);
|
|
}
|
|
|
|
/// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
|
|
const Query &Q, unsigned MaxRecurse) {
|
|
CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
|
|
assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!");
|
|
|
|
if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
|
|
if (Constant *CRHS = dyn_cast<Constant>(RHS))
|
|
return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.TD, Q.TLI);
|
|
|
|
// If we have a constant, make sure it is on the RHS.
|
|
std::swap(LHS, RHS);
|
|
Pred = CmpInst::getSwappedPredicate(Pred);
|
|
}
|
|
|
|
Type *ITy = GetCompareTy(LHS); // The return type.
|
|
Type *OpTy = LHS->getType(); // The operand type.
|
|
|
|
// icmp X, X -> true/false
|
|
// X icmp undef -> true/false. For example, icmp ugt %X, undef -> false
|
|
// because X could be 0.
|
|
if (LHS == RHS || isa<UndefValue>(RHS))
|
|
return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
|
|
|
|
// Special case logic when the operands have i1 type.
|
|
if (OpTy->getScalarType()->isIntegerTy(1)) {
|
|
switch (Pred) {
|
|
default: break;
|
|
case ICmpInst::ICMP_EQ:
|
|
// X == 1 -> X
|
|
if (match(RHS, m_One()))
|
|
return LHS;
|
|
break;
|
|
case ICmpInst::ICMP_NE:
|
|
// X != 0 -> X
|
|
if (match(RHS, m_Zero()))
|
|
return LHS;
|
|
break;
|
|
case ICmpInst::ICMP_UGT:
|
|
// X >u 0 -> X
|
|
if (match(RHS, m_Zero()))
|
|
return LHS;
|
|
break;
|
|
case ICmpInst::ICMP_UGE:
|
|
// X >=u 1 -> X
|
|
if (match(RHS, m_One()))
|
|
return LHS;
|
|
break;
|
|
case ICmpInst::ICMP_SLT:
|
|
// X <s 0 -> X
|
|
if (match(RHS, m_Zero()))
|
|
return LHS;
|
|
break;
|
|
case ICmpInst::ICMP_SLE:
|
|
// X <=s -1 -> X
|
|
if (match(RHS, m_One()))
|
|
return LHS;
|
|
break;
|
|
}
|
|
}
|
|
|
|
// icmp <object*>, <object*/null> - Different identified objects have
|
|
// different addresses (unless null), and what's more the address of an
|
|
// identified local is never equal to another argument (again, barring null).
|
|
// Note that generalizing to the case where LHS is a global variable address
|
|
// or null is pointless, since if both LHS and RHS are constants then we
|
|
// already constant folded the compare, and if only one of them is then we
|
|
// moved it to RHS already.
|
|
Value *LHSPtr = LHS->stripPointerCasts();
|
|
Value *RHSPtr = RHS->stripPointerCasts();
|
|
if (LHSPtr == RHSPtr)
|
|
return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
|
|
|
|
// Be more aggressive about stripping pointer adjustments when checking a
|
|
// comparison of an alloca address to another object. We can rip off all
|
|
// inbounds GEP operations, even if they are variable.
|
|
LHSPtr = LHSPtr->stripInBoundsOffsets();
|
|
if (llvm::isIdentifiedObject(LHSPtr)) {
|
|
RHSPtr = RHSPtr->stripInBoundsOffsets();
|
|
if (llvm::isKnownNonNull(LHSPtr) || llvm::isKnownNonNull(RHSPtr)) {
|
|
// If both sides are different identified objects, they aren't equal
|
|
// unless they're null.
|
|
if (LHSPtr != RHSPtr && llvm::isIdentifiedObject(RHSPtr) &&
|
|
Pred == CmpInst::ICMP_EQ)
|
|
return ConstantInt::get(ITy, false);
|
|
|
|
// A local identified object (alloca or noalias call) can't equal any
|
|
// incoming argument, unless they're both null or they belong to
|
|
// different functions. The latter happens during inlining.
|
|
if (Instruction *LHSInst = dyn_cast<Instruction>(LHSPtr))
|
|
if (Argument *RHSArg = dyn_cast<Argument>(RHSPtr))
|
|
if (LHSInst->getParent()->getParent() == RHSArg->getParent() &&
|
|
Pred == CmpInst::ICMP_EQ)
|
|
return ConstantInt::get(ITy, false);
|
|
}
|
|
|
|
// Assume that the constant null is on the right.
|
|
if (llvm::isKnownNonNull(LHSPtr) && isa<ConstantPointerNull>(RHSPtr)) {
|
|
if (Pred == CmpInst::ICMP_EQ)
|
|
return ConstantInt::get(ITy, false);
|
|
else if (Pred == CmpInst::ICMP_NE)
|
|
return ConstantInt::get(ITy, true);
|
|
}
|
|
} else if (Argument *LHSArg = dyn_cast<Argument>(LHSPtr)) {
|
|
RHSPtr = RHSPtr->stripInBoundsOffsets();
|
|
// An alloca can't be equal to an argument unless they come from separate
|
|
// functions via inlining.
|
|
if (AllocaInst *RHSInst = dyn_cast<AllocaInst>(RHSPtr)) {
|
|
if (LHSArg->getParent() == RHSInst->getParent()->getParent()) {
|
|
if (Pred == CmpInst::ICMP_EQ)
|
|
return ConstantInt::get(ITy, false);
|
|
else if (Pred == CmpInst::ICMP_NE)
|
|
return ConstantInt::get(ITy, true);
|
|
}
|
|
}
|
|
}
|
|
|
|
// If we are comparing with zero then try hard since this is a common case.
|
|
if (match(RHS, m_Zero())) {
|
|
bool LHSKnownNonNegative, LHSKnownNegative;
|
|
switch (Pred) {
|
|
default: llvm_unreachable("Unknown ICmp predicate!");
|
|
case ICmpInst::ICMP_ULT:
|
|
return getFalse(ITy);
|
|
case ICmpInst::ICMP_UGE:
|
|
return getTrue(ITy);
|
|
case ICmpInst::ICMP_EQ:
|
|
case ICmpInst::ICMP_ULE:
|
|
if (isKnownNonZero(LHS, Q.TD))
|
|
return getFalse(ITy);
|
|
break;
|
|
case ICmpInst::ICMP_NE:
|
|
case ICmpInst::ICMP_UGT:
|
|
if (isKnownNonZero(LHS, Q.TD))
|
|
return getTrue(ITy);
|
|
break;
|
|
case ICmpInst::ICMP_SLT:
|
|
ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
|
|
if (LHSKnownNegative)
|
|
return getTrue(ITy);
|
|
if (LHSKnownNonNegative)
|
|
return getFalse(ITy);
|
|
break;
|
|
case ICmpInst::ICMP_SLE:
|
|
ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
|
|
if (LHSKnownNegative)
|
|
return getTrue(ITy);
|
|
if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.TD))
|
|
return getFalse(ITy);
|
|
break;
|
|
case ICmpInst::ICMP_SGE:
|
|
ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
|
|
if (LHSKnownNegative)
|
|
return getFalse(ITy);
|
|
if (LHSKnownNonNegative)
|
|
return getTrue(ITy);
|
|
break;
|
|
case ICmpInst::ICMP_SGT:
|
|
ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, Q.TD);
|
|
if (LHSKnownNegative)
|
|
return getFalse(ITy);
|
|
if (LHSKnownNonNegative && isKnownNonZero(LHS, Q.TD))
|
|
return getTrue(ITy);
|
|
break;
|
|
}
|
|
}
|
|
|
|
// See if we are doing a comparison with a constant integer.
|
|
if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
|
|
// Rule out tautological comparisons (eg., ult 0 or uge 0).
|
|
ConstantRange RHS_CR = ICmpInst::makeConstantRange(Pred, CI->getValue());
|
|
if (RHS_CR.isEmptySet())
|
|
return ConstantInt::getFalse(CI->getContext());
|
|
if (RHS_CR.isFullSet())
|
|
return ConstantInt::getTrue(CI->getContext());
|
|
|
|
// Many binary operators with constant RHS have easy to compute constant
|
|
// range. Use them to check whether the comparison is a tautology.
|
|
uint32_t Width = CI->getBitWidth();
|
|
APInt Lower = APInt(Width, 0);
|
|
APInt Upper = APInt(Width, 0);
|
|
ConstantInt *CI2;
|
|
if (match(LHS, m_URem(m_Value(), m_ConstantInt(CI2)))) {
|
|
// 'urem x, CI2' produces [0, CI2).
|
|
Upper = CI2->getValue();
|
|
} else if (match(LHS, m_SRem(m_Value(), m_ConstantInt(CI2)))) {
|
|
// 'srem x, CI2' produces (-|CI2|, |CI2|).
|
|
Upper = CI2->getValue().abs();
|
|
Lower = (-Upper) + 1;
|
|
} else if (match(LHS, m_UDiv(m_ConstantInt(CI2), m_Value()))) {
|
|
// 'udiv CI2, x' produces [0, CI2].
|
|
Upper = CI2->getValue() + 1;
|
|
} else if (match(LHS, m_UDiv(m_Value(), m_ConstantInt(CI2)))) {
|
|
// 'udiv x, CI2' produces [0, UINT_MAX / CI2].
|
|
APInt NegOne = APInt::getAllOnesValue(Width);
|
|
if (!CI2->isZero())
|
|
Upper = NegOne.udiv(CI2->getValue()) + 1;
|
|
} else if (match(LHS, m_SDiv(m_Value(), m_ConstantInt(CI2)))) {
|
|
// 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2].
|
|
APInt IntMin = APInt::getSignedMinValue(Width);
|
|
APInt IntMax = APInt::getSignedMaxValue(Width);
|
|
APInt Val = CI2->getValue().abs();
|
|
if (!Val.isMinValue()) {
|
|
Lower = IntMin.sdiv(Val);
|
|
Upper = IntMax.sdiv(Val) + 1;
|
|
}
|
|
} else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) {
|
|
// 'lshr x, CI2' produces [0, UINT_MAX >> CI2].
|
|
APInt NegOne = APInt::getAllOnesValue(Width);
|
|
if (CI2->getValue().ult(Width))
|
|
Upper = NegOne.lshr(CI2->getValue()) + 1;
|
|
} else if (match(LHS, m_AShr(m_Value(), m_ConstantInt(CI2)))) {
|
|
// 'ashr x, CI2' produces [INT_MIN >> CI2, INT_MAX >> CI2].
|
|
APInt IntMin = APInt::getSignedMinValue(Width);
|
|
APInt IntMax = APInt::getSignedMaxValue(Width);
|
|
if (CI2->getValue().ult(Width)) {
|
|
Lower = IntMin.ashr(CI2->getValue());
|
|
Upper = IntMax.ashr(CI2->getValue()) + 1;
|
|
}
|
|
} else if (match(LHS, m_Or(m_Value(), m_ConstantInt(CI2)))) {
|
|
// 'or x, CI2' produces [CI2, UINT_MAX].
|
|
Lower = CI2->getValue();
|
|
} else if (match(LHS, m_And(m_Value(), m_ConstantInt(CI2)))) {
|
|
// 'and x, CI2' produces [0, CI2].
|
|
Upper = CI2->getValue() + 1;
|
|
}
|
|
if (Lower != Upper) {
|
|
ConstantRange LHS_CR = ConstantRange(Lower, Upper);
|
|
if (RHS_CR.contains(LHS_CR))
|
|
return ConstantInt::getTrue(RHS->getContext());
|
|
if (RHS_CR.inverse().contains(LHS_CR))
|
|
return ConstantInt::getFalse(RHS->getContext());
|
|
}
|
|
}
|
|
|
|
// Compare of cast, for example (zext X) != 0 -> X != 0
|
|
if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
|
|
Instruction *LI = cast<CastInst>(LHS);
|
|
Value *SrcOp = LI->getOperand(0);
|
|
Type *SrcTy = SrcOp->getType();
|
|
Type *DstTy = LI->getType();
|
|
|
|
// Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
|
|
// if the integer type is the same size as the pointer type.
|
|
if (MaxRecurse && Q.TD && isa<PtrToIntInst>(LI) &&
|
|
Q.TD->getPointerSizeInBits() == DstTy->getPrimitiveSizeInBits()) {
|
|
if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
|
|
// Transfer the cast to the constant.
|
|
if (Value *V = SimplifyICmpInst(Pred, SrcOp,
|
|
ConstantExpr::getIntToPtr(RHSC, SrcTy),
|
|
Q, MaxRecurse-1))
|
|
return V;
|
|
} else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
|
|
if (RI->getOperand(0)->getType() == SrcTy)
|
|
// Compare without the cast.
|
|
if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
|
|
Q, MaxRecurse-1))
|
|
return V;
|
|
}
|
|
}
|
|
|
|
if (isa<ZExtInst>(LHS)) {
|
|
// Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
|
|
// same type.
|
|
if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
|
|
if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
|
|
// Compare X and Y. Note that signed predicates become unsigned.
|
|
if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
|
|
SrcOp, RI->getOperand(0), Q,
|
|
MaxRecurse-1))
|
|
return V;
|
|
}
|
|
// Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
|
|
// too. If not, then try to deduce the result of the comparison.
|
|
else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
|
|
// Compute the constant that would happen if we truncated to SrcTy then
|
|
// reextended to DstTy.
|
|
Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
|
|
Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
|
|
|
|
// If the re-extended constant didn't change then this is effectively
|
|
// also a case of comparing two zero-extended values.
|
|
if (RExt == CI && MaxRecurse)
|
|
if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
|
|
SrcOp, Trunc, Q, MaxRecurse-1))
|
|
return V;
|
|
|
|
// Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
|
|
// there. Use this to work out the result of the comparison.
|
|
if (RExt != CI) {
|
|
switch (Pred) {
|
|
default: llvm_unreachable("Unknown ICmp predicate!");
|
|
// LHS <u RHS.
|
|
case ICmpInst::ICMP_EQ:
|
|
case ICmpInst::ICMP_UGT:
|
|
case ICmpInst::ICMP_UGE:
|
|
return ConstantInt::getFalse(CI->getContext());
|
|
|
|
case ICmpInst::ICMP_NE:
|
|
case ICmpInst::ICMP_ULT:
|
|
case ICmpInst::ICMP_ULE:
|
|
return ConstantInt::getTrue(CI->getContext());
|
|
|
|
// LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
|
|
// is non-negative then LHS <s RHS.
|
|
case ICmpInst::ICMP_SGT:
|
|
case ICmpInst::ICMP_SGE:
|
|
return CI->getValue().isNegative() ?
|
|
ConstantInt::getTrue(CI->getContext()) :
|
|
ConstantInt::getFalse(CI->getContext());
|
|
|
|
case ICmpInst::ICMP_SLT:
|
|
case ICmpInst::ICMP_SLE:
|
|
return CI->getValue().isNegative() ?
|
|
ConstantInt::getFalse(CI->getContext()) :
|
|
ConstantInt::getTrue(CI->getContext());
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (isa<SExtInst>(LHS)) {
|
|
// Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
|
|
// same type.
|
|
if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
|
|
if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
|
|
// Compare X and Y. Note that the predicate does not change.
|
|
if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
|
|
Q, MaxRecurse-1))
|
|
return V;
|
|
}
|
|
// Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
|
|
// too. If not, then try to deduce the result of the comparison.
|
|
else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
|
|
// Compute the constant that would happen if we truncated to SrcTy then
|
|
// reextended to DstTy.
|
|
Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
|
|
Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
|
|
|
|
// If the re-extended constant didn't change then this is effectively
|
|
// also a case of comparing two sign-extended values.
|
|
if (RExt == CI && MaxRecurse)
|
|
if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1))
|
|
return V;
|
|
|
|
// Otherwise the upper bits of LHS are all equal, while RHS has varying
|
|
// bits there. Use this to work out the result of the comparison.
|
|
if (RExt != CI) {
|
|
switch (Pred) {
|
|
default: llvm_unreachable("Unknown ICmp predicate!");
|
|
case ICmpInst::ICMP_EQ:
|
|
return ConstantInt::getFalse(CI->getContext());
|
|
case ICmpInst::ICMP_NE:
|
|
return ConstantInt::getTrue(CI->getContext());
|
|
|
|
// If RHS is non-negative then LHS <s RHS. If RHS is negative then
|
|
// LHS >s RHS.
|
|
case ICmpInst::ICMP_SGT:
|
|
case ICmpInst::ICMP_SGE:
|
|
return CI->getValue().isNegative() ?
|
|
ConstantInt::getTrue(CI->getContext()) :
|
|
ConstantInt::getFalse(CI->getContext());
|
|
case ICmpInst::ICMP_SLT:
|
|
case ICmpInst::ICMP_SLE:
|
|
return CI->getValue().isNegative() ?
|
|
ConstantInt::getFalse(CI->getContext()) :
|
|
ConstantInt::getTrue(CI->getContext());
|
|
|
|
// If LHS is non-negative then LHS <u RHS. If LHS is negative then
|
|
// LHS >u RHS.
|
|
case ICmpInst::ICMP_UGT:
|
|
case ICmpInst::ICMP_UGE:
|
|
// Comparison is true iff the LHS <s 0.
|
|
if (MaxRecurse)
|
|
if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
|
|
Constant::getNullValue(SrcTy),
|
|
Q, MaxRecurse-1))
|
|
return V;
|
|
break;
|
|
case ICmpInst::ICMP_ULT:
|
|
case ICmpInst::ICMP_ULE:
|
|
// Comparison is true iff the LHS >=s 0.
|
|
if (MaxRecurse)
|
|
if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
|
|
Constant::getNullValue(SrcTy),
|
|
Q, MaxRecurse-1))
|
|
return V;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Special logic for binary operators.
|
|
BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
|
|
BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
|
|
if (MaxRecurse && (LBO || RBO)) {
|
|
// Analyze the case when either LHS or RHS is an add instruction.
|
|
Value *A = 0, *B = 0, *C = 0, *D = 0;
|
|
// LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
|
|
bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
|
|
if (LBO && LBO->getOpcode() == Instruction::Add) {
|
|
A = LBO->getOperand(0); B = LBO->getOperand(1);
|
|
NoLHSWrapProblem = ICmpInst::isEquality(Pred) ||
|
|
(CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) ||
|
|
(CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap());
|
|
}
|
|
if (RBO && RBO->getOpcode() == Instruction::Add) {
|
|
C = RBO->getOperand(0); D = RBO->getOperand(1);
|
|
NoRHSWrapProblem = ICmpInst::isEquality(Pred) ||
|
|
(CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) ||
|
|
(CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap());
|
|
}
|
|
|
|
// icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
|
|
if ((A == RHS || B == RHS) && NoLHSWrapProblem)
|
|
if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
|
|
Constant::getNullValue(RHS->getType()),
|
|
Q, MaxRecurse-1))
|
|
return V;
|
|
|
|
// icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
|
|
if ((C == LHS || D == LHS) && NoRHSWrapProblem)
|
|
if (Value *V = SimplifyICmpInst(Pred,
|
|
Constant::getNullValue(LHS->getType()),
|
|
C == LHS ? D : C, Q, MaxRecurse-1))
|
|
return V;
|
|
|
|
// icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
|
|
if (A && C && (A == C || A == D || B == C || B == D) &&
|
|
NoLHSWrapProblem && NoRHSWrapProblem) {
|
|
// Determine Y and Z in the form icmp (X+Y), (X+Z).
|
|
Value *Y = (A == C || A == D) ? B : A;
|
|
Value *Z = (C == A || C == B) ? D : C;
|
|
if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse-1))
|
|
return V;
|
|
}
|
|
}
|
|
|
|
if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
|
|
bool KnownNonNegative, KnownNegative;
|
|
switch (Pred) {
|
|
default:
|
|
break;
|
|
case ICmpInst::ICMP_SGT:
|
|
case ICmpInst::ICMP_SGE:
|
|
ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.TD);
|
|
if (!KnownNonNegative)
|
|
break;
|
|
// fall-through
|
|
case ICmpInst::ICMP_EQ:
|
|
case ICmpInst::ICMP_UGT:
|
|
case ICmpInst::ICMP_UGE:
|
|
return getFalse(ITy);
|
|
case ICmpInst::ICMP_SLT:
|
|
case ICmpInst::ICMP_SLE:
|
|
ComputeSignBit(LHS, KnownNonNegative, KnownNegative, Q.TD);
|
|
if (!KnownNonNegative)
|
|
break;
|
|
// fall-through
|
|
case ICmpInst::ICMP_NE:
|
|
case ICmpInst::ICMP_ULT:
|
|
case ICmpInst::ICMP_ULE:
|
|
return getTrue(ITy);
|
|
}
|
|
}
|
|
if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
|
|
bool KnownNonNegative, KnownNegative;
|
|
switch (Pred) {
|
|
default:
|
|
break;
|
|
case ICmpInst::ICMP_SGT:
|
|
case ICmpInst::ICMP_SGE:
|
|
ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.TD);
|
|
if (!KnownNonNegative)
|
|
break;
|
|
// fall-through
|
|
case ICmpInst::ICMP_NE:
|
|
case ICmpInst::ICMP_UGT:
|
|
case ICmpInst::ICMP_UGE:
|
|
return getTrue(ITy);
|
|
case ICmpInst::ICMP_SLT:
|
|
case ICmpInst::ICMP_SLE:
|
|
ComputeSignBit(RHS, KnownNonNegative, KnownNegative, Q.TD);
|
|
if (!KnownNonNegative)
|
|
break;
|
|
// fall-through
|
|
case ICmpInst::ICMP_EQ:
|
|
case ICmpInst::ICMP_ULT:
|
|
case ICmpInst::ICMP_ULE:
|
|
return getFalse(ITy);
|
|
}
|
|
}
|
|
|
|
// x udiv y <=u x.
|
|
if (LBO && match(LBO, m_UDiv(m_Specific(RHS), m_Value()))) {
|
|
// icmp pred (X /u Y), X
|
|
if (Pred == ICmpInst::ICMP_UGT)
|
|
return getFalse(ITy);
|
|
if (Pred == ICmpInst::ICMP_ULE)
|
|
return getTrue(ITy);
|
|
}
|
|
|
|
if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
|
|
LBO->getOperand(1) == RBO->getOperand(1)) {
|
|
switch (LBO->getOpcode()) {
|
|
default: break;
|
|
case Instruction::UDiv:
|
|
case Instruction::LShr:
|
|
if (ICmpInst::isSigned(Pred))
|
|
break;
|
|
// fall-through
|
|
case Instruction::SDiv:
|
|
case Instruction::AShr:
|
|
if (!LBO->isExact() || !RBO->isExact())
|
|
break;
|
|
if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
|
|
RBO->getOperand(0), Q, MaxRecurse-1))
|
|
return V;
|
|
break;
|
|
case Instruction::Shl: {
|
|
bool NUW = LBO->hasNoUnsignedWrap() && RBO->hasNoUnsignedWrap();
|
|
bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
|
|
if (!NUW && !NSW)
|
|
break;
|
|
if (!NSW && ICmpInst::isSigned(Pred))
|
|
break;
|
|
if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
|
|
RBO->getOperand(0), Q, MaxRecurse-1))
|
|
return V;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Simplify comparisons involving max/min.
|
|
Value *A, *B;
|
|
CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE;
|
|
CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
|
|
|
|
// Signed variants on "max(a,b)>=a -> true".
|
|
if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
|
|
if (A != RHS) std::swap(A, B); // smax(A, B) pred A.
|
|
EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
|
|
// We analyze this as smax(A, B) pred A.
|
|
P = Pred;
|
|
} else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
|
|
(A == LHS || B == LHS)) {
|
|
if (A != LHS) std::swap(A, B); // A pred smax(A, B).
|
|
EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
|
|
// We analyze this as smax(A, B) swapped-pred A.
|
|
P = CmpInst::getSwappedPredicate(Pred);
|
|
} else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
|
|
(A == RHS || B == RHS)) {
|
|
if (A != RHS) std::swap(A, B); // smin(A, B) pred A.
|
|
EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
|
|
// We analyze this as smax(-A, -B) swapped-pred -A.
|
|
// Note that we do not need to actually form -A or -B thanks to EqP.
|
|
P = CmpInst::getSwappedPredicate(Pred);
|
|
} else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
|
|
(A == LHS || B == LHS)) {
|
|
if (A != LHS) std::swap(A, B); // A pred smin(A, B).
|
|
EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
|
|
// We analyze this as smax(-A, -B) pred -A.
|
|
// Note that we do not need to actually form -A or -B thanks to EqP.
|
|
P = Pred;
|
|
}
|
|
if (P != CmpInst::BAD_ICMP_PREDICATE) {
|
|
// Cases correspond to "max(A, B) p A".
|
|
switch (P) {
|
|
default:
|
|
break;
|
|
case CmpInst::ICMP_EQ:
|
|
case CmpInst::ICMP_SLE:
|
|
// Equivalent to "A EqP B". This may be the same as the condition tested
|
|
// in the max/min; if so, we can just return that.
|
|
if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
|
|
return V;
|
|
if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
|
|
return V;
|
|
// Otherwise, see if "A EqP B" simplifies.
|
|
if (MaxRecurse)
|
|
if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
|
|
return V;
|
|
break;
|
|
case CmpInst::ICMP_NE:
|
|
case CmpInst::ICMP_SGT: {
|
|
CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
|
|
// Equivalent to "A InvEqP B". This may be the same as the condition
|
|
// tested in the max/min; if so, we can just return that.
|
|
if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
|
|
return V;
|
|
if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
|
|
return V;
|
|
// Otherwise, see if "A InvEqP B" simplifies.
|
|
if (MaxRecurse)
|
|
if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
|
|
return V;
|
|
break;
|
|
}
|
|
case CmpInst::ICMP_SGE:
|
|
// Always true.
|
|
return getTrue(ITy);
|
|
case CmpInst::ICMP_SLT:
|
|
// Always false.
|
|
return getFalse(ITy);
|
|
}
|
|
}
|
|
|
|
// Unsigned variants on "max(a,b)>=a -> true".
|
|
P = CmpInst::BAD_ICMP_PREDICATE;
|
|
if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
|
|
if (A != RHS) std::swap(A, B); // umax(A, B) pred A.
|
|
EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
|
|
// We analyze this as umax(A, B) pred A.
|
|
P = Pred;
|
|
} else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
|
|
(A == LHS || B == LHS)) {
|
|
if (A != LHS) std::swap(A, B); // A pred umax(A, B).
|
|
EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
|
|
// We analyze this as umax(A, B) swapped-pred A.
|
|
P = CmpInst::getSwappedPredicate(Pred);
|
|
} else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
|
|
(A == RHS || B == RHS)) {
|
|
if (A != RHS) std::swap(A, B); // umin(A, B) pred A.
|
|
EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
|
|
// We analyze this as umax(-A, -B) swapped-pred -A.
|
|
// Note that we do not need to actually form -A or -B thanks to EqP.
|
|
P = CmpInst::getSwappedPredicate(Pred);
|
|
} else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
|
|
(A == LHS || B == LHS)) {
|
|
if (A != LHS) std::swap(A, B); // A pred umin(A, B).
|
|
EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
|
|
// We analyze this as umax(-A, -B) pred -A.
|
|
// Note that we do not need to actually form -A or -B thanks to EqP.
|
|
P = Pred;
|
|
}
|
|
if (P != CmpInst::BAD_ICMP_PREDICATE) {
|
|
// Cases correspond to "max(A, B) p A".
|
|
switch (P) {
|
|
default:
|
|
break;
|
|
case CmpInst::ICMP_EQ:
|
|
case CmpInst::ICMP_ULE:
|
|
// Equivalent to "A EqP B". This may be the same as the condition tested
|
|
// in the max/min; if so, we can just return that.
|
|
if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
|
|
return V;
|
|
if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
|
|
return V;
|
|
// Otherwise, see if "A EqP B" simplifies.
|
|
if (MaxRecurse)
|
|
if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse-1))
|
|
return V;
|
|
break;
|
|
case CmpInst::ICMP_NE:
|
|
case CmpInst::ICMP_UGT: {
|
|
CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
|
|
// Equivalent to "A InvEqP B". This may be the same as the condition
|
|
// tested in the max/min; if so, we can just return that.
|
|
if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
|
|
return V;
|
|
if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
|
|
return V;
|
|
// Otherwise, see if "A InvEqP B" simplifies.
|
|
if (MaxRecurse)
|
|
if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse-1))
|
|
return V;
|
|
break;
|
|
}
|
|
case CmpInst::ICMP_UGE:
|
|
// Always true.
|
|
return getTrue(ITy);
|
|
case CmpInst::ICMP_ULT:
|
|
// Always false.
|
|
return getFalse(ITy);
|
|
}
|
|
}
|
|
|
|
// Variants on "max(x,y) >= min(x,z)".
|
|
Value *C, *D;
|
|
if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
|
|
match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
|
|
(A == C || A == D || B == C || B == D)) {
|
|
// max(x, ?) pred min(x, ?).
|
|
if (Pred == CmpInst::ICMP_SGE)
|
|
// Always true.
|
|
return getTrue(ITy);
|
|
if (Pred == CmpInst::ICMP_SLT)
|
|
// Always false.
|
|
return getFalse(ITy);
|
|
} else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
|
|
match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
|
|
(A == C || A == D || B == C || B == D)) {
|
|
// min(x, ?) pred max(x, ?).
|
|
if (Pred == CmpInst::ICMP_SLE)
|
|
// Always true.
|
|
return getTrue(ITy);
|
|
if (Pred == CmpInst::ICMP_SGT)
|
|
// Always false.
|
|
return getFalse(ITy);
|
|
} else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
|
|
match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
|
|
(A == C || A == D || B == C || B == D)) {
|
|
// max(x, ?) pred min(x, ?).
|
|
if (Pred == CmpInst::ICMP_UGE)
|
|
// Always true.
|
|
return getTrue(ITy);
|
|
if (Pred == CmpInst::ICMP_ULT)
|
|
// Always false.
|
|
return getFalse(ITy);
|
|
} else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
|
|
match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
|
|
(A == C || A == D || B == C || B == D)) {
|
|
// min(x, ?) pred max(x, ?).
|
|
if (Pred == CmpInst::ICMP_ULE)
|
|
// Always true.
|
|
return getTrue(ITy);
|
|
if (Pred == CmpInst::ICMP_UGT)
|
|
// Always false.
|
|
return getFalse(ITy);
|
|
}
|
|
|
|
// Simplify comparisons of related pointers using a powerful, recursive
|
|
// GEP-walk when we have target data available..
|
|
if (Q.TD && LHS->getType()->isPointerTy() && RHS->getType()->isPointerTy())
|
|
if (Constant *C = computePointerICmp(*Q.TD, Pred, LHS, RHS))
|
|
return C;
|
|
|
|
if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
|
|
if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) {
|
|
if (GLHS->getPointerOperand() == GRHS->getPointerOperand() &&
|
|
GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() &&
|
|
(ICmpInst::isEquality(Pred) ||
|
|
(GLHS->isInBounds() && GRHS->isInBounds() &&
|
|
Pred == ICmpInst::getSignedPredicate(Pred)))) {
|
|
// The bases are equal and the indices are constant. Build a constant
|
|
// expression GEP with the same indices and a null base pointer to see
|
|
// what constant folding can make out of it.
|
|
Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType());
|
|
SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end());
|
|
Constant *NewLHS = ConstantExpr::getGetElementPtr(Null, IndicesLHS);
|
|
|
|
SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end());
|
|
Constant *NewRHS = ConstantExpr::getGetElementPtr(Null, IndicesRHS);
|
|
return ConstantExpr::getICmp(Pred, NewLHS, NewRHS);
|
|
}
|
|
}
|
|
}
|
|
|
|
// If the comparison is with the result of a select instruction, check whether
|
|
// comparing with either branch of the select always yields the same value.
|
|
if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
|
|
if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
|
|
return V;
|
|
|
|
// If the comparison is with the result of a phi instruction, check whether
|
|
// doing the compare with each incoming phi value yields a common result.
|
|
if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
|
|
if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
|
|
return V;
|
|
|
|
return 0;
|
|
}
|
|
|
|
Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
|
|
const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifyICmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT),
|
|
RecursionLimit);
|
|
}
|
|
|
|
/// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
|
|
const Query &Q, unsigned MaxRecurse) {
|
|
CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
|
|
assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!");
|
|
|
|
if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
|
|
if (Constant *CRHS = dyn_cast<Constant>(RHS))
|
|
return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.TD, Q.TLI);
|
|
|
|
// If we have a constant, make sure it is on the RHS.
|
|
std::swap(LHS, RHS);
|
|
Pred = CmpInst::getSwappedPredicate(Pred);
|
|
}
|
|
|
|
// Fold trivial predicates.
|
|
if (Pred == FCmpInst::FCMP_FALSE)
|
|
return ConstantInt::get(GetCompareTy(LHS), 0);
|
|
if (Pred == FCmpInst::FCMP_TRUE)
|
|
return ConstantInt::get(GetCompareTy(LHS), 1);
|
|
|
|
if (isa<UndefValue>(RHS)) // fcmp pred X, undef -> undef
|
|
return UndefValue::get(GetCompareTy(LHS));
|
|
|
|
// fcmp x,x -> true/false. Not all compares are foldable.
|
|
if (LHS == RHS) {
|
|
if (CmpInst::isTrueWhenEqual(Pred))
|
|
return ConstantInt::get(GetCompareTy(LHS), 1);
|
|
if (CmpInst::isFalseWhenEqual(Pred))
|
|
return ConstantInt::get(GetCompareTy(LHS), 0);
|
|
}
|
|
|
|
// Handle fcmp with constant RHS
|
|
if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
|
|
// If the constant is a nan, see if we can fold the comparison based on it.
|
|
if (ConstantFP *CFP = dyn_cast<ConstantFP>(RHSC)) {
|
|
if (CFP->getValueAPF().isNaN()) {
|
|
if (FCmpInst::isOrdered(Pred)) // True "if ordered and foo"
|
|
return ConstantInt::getFalse(CFP->getContext());
|
|
assert(FCmpInst::isUnordered(Pred) &&
|
|
"Comparison must be either ordered or unordered!");
|
|
// True if unordered.
|
|
return ConstantInt::getTrue(CFP->getContext());
|
|
}
|
|
// Check whether the constant is an infinity.
|
|
if (CFP->getValueAPF().isInfinity()) {
|
|
if (CFP->getValueAPF().isNegative()) {
|
|
switch (Pred) {
|
|
case FCmpInst::FCMP_OLT:
|
|
// No value is ordered and less than negative infinity.
|
|
return ConstantInt::getFalse(CFP->getContext());
|
|
case FCmpInst::FCMP_UGE:
|
|
// All values are unordered with or at least negative infinity.
|
|
return ConstantInt::getTrue(CFP->getContext());
|
|
default:
|
|
break;
|
|
}
|
|
} else {
|
|
switch (Pred) {
|
|
case FCmpInst::FCMP_OGT:
|
|
// No value is ordered and greater than infinity.
|
|
return ConstantInt::getFalse(CFP->getContext());
|
|
case FCmpInst::FCMP_ULE:
|
|
// All values are unordered with and at most infinity.
|
|
return ConstantInt::getTrue(CFP->getContext());
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// If the comparison is with the result of a select instruction, check whether
|
|
// comparing with either branch of the select always yields the same value.
|
|
if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
|
|
if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse))
|
|
return V;
|
|
|
|
// If the comparison is with the result of a phi instruction, check whether
|
|
// doing the compare with each incoming phi value yields a common result.
|
|
if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
|
|
if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
|
|
return V;
|
|
|
|
return 0;
|
|
}
|
|
|
|
Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
|
|
const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifyFCmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT),
|
|
RecursionLimit);
|
|
}
|
|
|
|
/// SimplifySelectInst - Given operands for a SelectInst, see if we can fold
|
|
/// the result. If not, this returns null.
|
|
static Value *SimplifySelectInst(Value *CondVal, Value *TrueVal,
|
|
Value *FalseVal, const Query &Q,
|
|
unsigned MaxRecurse) {
|
|
// select true, X, Y -> X
|
|
// select false, X, Y -> Y
|
|
if (ConstantInt *CB = dyn_cast<ConstantInt>(CondVal))
|
|
return CB->getZExtValue() ? TrueVal : FalseVal;
|
|
|
|
// select C, X, X -> X
|
|
if (TrueVal == FalseVal)
|
|
return TrueVal;
|
|
|
|
if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y
|
|
if (isa<Constant>(TrueVal))
|
|
return TrueVal;
|
|
return FalseVal;
|
|
}
|
|
if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X
|
|
return FalseVal;
|
|
if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
|
|
return TrueVal;
|
|
|
|
return 0;
|
|
}
|
|
|
|
Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
|
|
const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifySelectInst(Cond, TrueVal, FalseVal, Query (TD, TLI, DT),
|
|
RecursionLimit);
|
|
}
|
|
|
|
/// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
static Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const Query &Q, unsigned) {
|
|
// The type of the GEP pointer operand.
|
|
PointerType *PtrTy = dyn_cast<PointerType>(Ops[0]->getType());
|
|
// The GEP pointer operand is not a pointer, it's a vector of pointers.
|
|
if (!PtrTy)
|
|
return 0;
|
|
|
|
// getelementptr P -> P.
|
|
if (Ops.size() == 1)
|
|
return Ops[0];
|
|
|
|
if (isa<UndefValue>(Ops[0])) {
|
|
// Compute the (pointer) type returned by the GEP instruction.
|
|
Type *LastType = GetElementPtrInst::getIndexedType(PtrTy, Ops.slice(1));
|
|
Type *GEPTy = PointerType::get(LastType, PtrTy->getAddressSpace());
|
|
return UndefValue::get(GEPTy);
|
|
}
|
|
|
|
if (Ops.size() == 2) {
|
|
// getelementptr P, 0 -> P.
|
|
if (ConstantInt *C = dyn_cast<ConstantInt>(Ops[1]))
|
|
if (C->isZero())
|
|
return Ops[0];
|
|
// getelementptr P, N -> P if P points to a type of zero size.
|
|
if (Q.TD) {
|
|
Type *Ty = PtrTy->getElementType();
|
|
if (Ty->isSized() && Q.TD->getTypeAllocSize(Ty) == 0)
|
|
return Ops[0];
|
|
}
|
|
}
|
|
|
|
// Check to see if this is constant foldable.
|
|
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
|
|
if (!isa<Constant>(Ops[i]))
|
|
return 0;
|
|
|
|
return ConstantExpr::getGetElementPtr(cast<Constant>(Ops[0]), Ops.slice(1));
|
|
}
|
|
|
|
Value *llvm::SimplifyGEPInst(ArrayRef<Value *> Ops, const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifyGEPInst(Ops, Query (TD, TLI, DT), RecursionLimit);
|
|
}
|
|
|
|
/// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we
|
|
/// can fold the result. If not, this returns null.
|
|
static Value *SimplifyInsertValueInst(Value *Agg, Value *Val,
|
|
ArrayRef<unsigned> Idxs, const Query &Q,
|
|
unsigned) {
|
|
if (Constant *CAgg = dyn_cast<Constant>(Agg))
|
|
if (Constant *CVal = dyn_cast<Constant>(Val))
|
|
return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
|
|
|
|
// insertvalue x, undef, n -> x
|
|
if (match(Val, m_Undef()))
|
|
return Agg;
|
|
|
|
// insertvalue x, (extractvalue y, n), n
|
|
if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
|
|
if (EV->getAggregateOperand()->getType() == Agg->getType() &&
|
|
EV->getIndices() == Idxs) {
|
|
// insertvalue undef, (extractvalue y, n), n -> y
|
|
if (match(Agg, m_Undef()))
|
|
return EV->getAggregateOperand();
|
|
|
|
// insertvalue y, (extractvalue y, n), n -> y
|
|
if (Agg == EV->getAggregateOperand())
|
|
return Agg;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
Value *llvm::SimplifyInsertValueInst(Value *Agg, Value *Val,
|
|
ArrayRef<unsigned> Idxs,
|
|
const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifyInsertValueInst(Agg, Val, Idxs, Query (TD, TLI, DT),
|
|
RecursionLimit);
|
|
}
|
|
|
|
/// SimplifyPHINode - See if we can fold the given phi. If not, returns null.
|
|
static Value *SimplifyPHINode(PHINode *PN, const Query &Q) {
|
|
// If all of the PHI's incoming values are the same then replace the PHI node
|
|
// with the common value.
|
|
Value *CommonValue = 0;
|
|
bool HasUndefInput = false;
|
|
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
|
|
Value *Incoming = PN->getIncomingValue(i);
|
|
// If the incoming value is the phi node itself, it can safely be skipped.
|
|
if (Incoming == PN) continue;
|
|
if (isa<UndefValue>(Incoming)) {
|
|
// Remember that we saw an undef value, but otherwise ignore them.
|
|
HasUndefInput = true;
|
|
continue;
|
|
}
|
|
if (CommonValue && Incoming != CommonValue)
|
|
return 0; // Not the same, bail out.
|
|
CommonValue = Incoming;
|
|
}
|
|
|
|
// If CommonValue is null then all of the incoming values were either undef or
|
|
// equal to the phi node itself.
|
|
if (!CommonValue)
|
|
return UndefValue::get(PN->getType());
|
|
|
|
// If we have a PHI node like phi(X, undef, X), where X is defined by some
|
|
// instruction, we cannot return X as the result of the PHI node unless it
|
|
// dominates the PHI block.
|
|
if (HasUndefInput)
|
|
return ValueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : 0;
|
|
|
|
return CommonValue;
|
|
}
|
|
|
|
static Value *SimplifyTruncInst(Value *Op, Type *Ty, const Query &Q, unsigned) {
|
|
if (Constant *C = dyn_cast<Constant>(Op))
|
|
return ConstantFoldInstOperands(Instruction::Trunc, Ty, C, Q.TD, Q.TLI);
|
|
|
|
return 0;
|
|
}
|
|
|
|
Value *llvm::SimplifyTruncInst(Value *Op, Type *Ty, const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifyTruncInst(Op, Ty, Query (TD, TLI, DT), RecursionLimit);
|
|
}
|
|
|
|
//=== Helper functions for higher up the class hierarchy.
|
|
|
|
/// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
|
|
const Query &Q, unsigned MaxRecurse) {
|
|
switch (Opcode) {
|
|
case Instruction::Add:
|
|
return SimplifyAddInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
|
|
Q, MaxRecurse);
|
|
case Instruction::Sub:
|
|
return SimplifySubInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
|
|
Q, MaxRecurse);
|
|
case Instruction::Mul: return SimplifyMulInst (LHS, RHS, Q, MaxRecurse);
|
|
case Instruction::SDiv: return SimplifySDivInst(LHS, RHS, Q, MaxRecurse);
|
|
case Instruction::UDiv: return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse);
|
|
case Instruction::FDiv: return SimplifyFDivInst(LHS, RHS, Q, MaxRecurse);
|
|
case Instruction::SRem: return SimplifySRemInst(LHS, RHS, Q, MaxRecurse);
|
|
case Instruction::URem: return SimplifyURemInst(LHS, RHS, Q, MaxRecurse);
|
|
case Instruction::FRem: return SimplifyFRemInst(LHS, RHS, Q, MaxRecurse);
|
|
case Instruction::Shl:
|
|
return SimplifyShlInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
|
|
Q, MaxRecurse);
|
|
case Instruction::LShr:
|
|
return SimplifyLShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
|
|
case Instruction::AShr:
|
|
return SimplifyAShrInst(LHS, RHS, /*isExact*/false, Q, MaxRecurse);
|
|
case Instruction::And: return SimplifyAndInst(LHS, RHS, Q, MaxRecurse);
|
|
case Instruction::Or: return SimplifyOrInst (LHS, RHS, Q, MaxRecurse);
|
|
case Instruction::Xor: return SimplifyXorInst(LHS, RHS, Q, MaxRecurse);
|
|
default:
|
|
if (Constant *CLHS = dyn_cast<Constant>(LHS))
|
|
if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
|
|
Constant *COps[] = {CLHS, CRHS};
|
|
return ConstantFoldInstOperands(Opcode, LHS->getType(), COps, Q.TD,
|
|
Q.TLI);
|
|
}
|
|
|
|
// If the operation is associative, try some generic simplifications.
|
|
if (Instruction::isAssociative(Opcode))
|
|
if (Value *V = SimplifyAssociativeBinOp(Opcode, LHS, RHS, Q, MaxRecurse))
|
|
return V;
|
|
|
|
// If the operation is with the result of a select instruction check whether
|
|
// operating on either branch of the select always yields the same value.
|
|
if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
|
|
if (Value *V = ThreadBinOpOverSelect(Opcode, LHS, RHS, Q, MaxRecurse))
|
|
return V;
|
|
|
|
// If the operation is with the result of a phi instruction, check whether
|
|
// operating on all incoming values of the phi always yields the same value.
|
|
if (isa<PHINode>(LHS) || isa<PHINode>(RHS))
|
|
if (Value *V = ThreadBinOpOverPHI(Opcode, LHS, RHS, Q, MaxRecurse))
|
|
return V;
|
|
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
|
|
const DataLayout *TD, const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifyBinOp(Opcode, LHS, RHS, Query (TD, TLI, DT), RecursionLimit);
|
|
}
|
|
|
|
/// SimplifyCmpInst - Given operands for a CmpInst, see if we can
|
|
/// fold the result.
|
|
static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
|
|
const Query &Q, unsigned MaxRecurse) {
|
|
if (CmpInst::isIntPredicate((CmpInst::Predicate)Predicate))
|
|
return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
|
|
return SimplifyFCmpInst(Predicate, LHS, RHS, Q, MaxRecurse);
|
|
}
|
|
|
|
Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
|
|
const DataLayout *TD, const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return ::SimplifyCmpInst(Predicate, LHS, RHS, Query (TD, TLI, DT),
|
|
RecursionLimit);
|
|
}
|
|
|
|
static Value *SimplifyCallInst(CallInst *CI, const Query &) {
|
|
// call undef -> undef
|
|
if (isa<UndefValue>(CI->getCalledValue()))
|
|
return UndefValue::get(CI->getType());
|
|
|
|
return 0;
|
|
}
|
|
|
|
/// SimplifyInstruction - See if we can compute a simplified version of this
|
|
/// instruction. If not, this returns null.
|
|
Value *llvm::SimplifyInstruction(Instruction *I, const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
Value *Result;
|
|
|
|
switch (I->getOpcode()) {
|
|
default:
|
|
Result = ConstantFoldInstruction(I, TD, TLI);
|
|
break;
|
|
case Instruction::Add:
|
|
Result = SimplifyAddInst(I->getOperand(0), I->getOperand(1),
|
|
cast<BinaryOperator>(I)->hasNoSignedWrap(),
|
|
cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
|
|
TD, TLI, DT);
|
|
break;
|
|
case Instruction::Sub:
|
|
Result = SimplifySubInst(I->getOperand(0), I->getOperand(1),
|
|
cast<BinaryOperator>(I)->hasNoSignedWrap(),
|
|
cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
|
|
TD, TLI, DT);
|
|
break;
|
|
case Instruction::Mul:
|
|
Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
|
|
break;
|
|
case Instruction::SDiv:
|
|
Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
|
|
break;
|
|
case Instruction::UDiv:
|
|
Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
|
|
break;
|
|
case Instruction::FDiv:
|
|
Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
|
|
break;
|
|
case Instruction::SRem:
|
|
Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
|
|
break;
|
|
case Instruction::URem:
|
|
Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
|
|
break;
|
|
case Instruction::FRem:
|
|
Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
|
|
break;
|
|
case Instruction::Shl:
|
|
Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1),
|
|
cast<BinaryOperator>(I)->hasNoSignedWrap(),
|
|
cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
|
|
TD, TLI, DT);
|
|
break;
|
|
case Instruction::LShr:
|
|
Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
|
|
cast<BinaryOperator>(I)->isExact(),
|
|
TD, TLI, DT);
|
|
break;
|
|
case Instruction::AShr:
|
|
Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
|
|
cast<BinaryOperator>(I)->isExact(),
|
|
TD, TLI, DT);
|
|
break;
|
|
case Instruction::And:
|
|
Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
|
|
break;
|
|
case Instruction::Or:
|
|
Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
|
|
break;
|
|
case Instruction::Xor:
|
|
Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1), TD, TLI, DT);
|
|
break;
|
|
case Instruction::ICmp:
|
|
Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(),
|
|
I->getOperand(0), I->getOperand(1), TD, TLI, DT);
|
|
break;
|
|
case Instruction::FCmp:
|
|
Result = SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(),
|
|
I->getOperand(0), I->getOperand(1), TD, TLI, DT);
|
|
break;
|
|
case Instruction::Select:
|
|
Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1),
|
|
I->getOperand(2), TD, TLI, DT);
|
|
break;
|
|
case Instruction::GetElementPtr: {
|
|
SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end());
|
|
Result = SimplifyGEPInst(Ops, TD, TLI, DT);
|
|
break;
|
|
}
|
|
case Instruction::InsertValue: {
|
|
InsertValueInst *IV = cast<InsertValueInst>(I);
|
|
Result = SimplifyInsertValueInst(IV->getAggregateOperand(),
|
|
IV->getInsertedValueOperand(),
|
|
IV->getIndices(), TD, TLI, DT);
|
|
break;
|
|
}
|
|
case Instruction::PHI:
|
|
Result = SimplifyPHINode(cast<PHINode>(I), Query (TD, TLI, DT));
|
|
break;
|
|
case Instruction::Call:
|
|
Result = SimplifyCallInst(cast<CallInst>(I), Query (TD, TLI, DT));
|
|
break;
|
|
case Instruction::Trunc:
|
|
Result = SimplifyTruncInst(I->getOperand(0), I->getType(), TD, TLI, DT);
|
|
break;
|
|
}
|
|
|
|
/// If called on unreachable code, the above logic may report that the
|
|
/// instruction simplified to itself. Make life easier for users by
|
|
/// detecting that case here, returning a safe value instead.
|
|
return Result == I ? UndefValue::get(I->getType()) : Result;
|
|
}
|
|
|
|
/// \brief Implementation of recursive simplification through an instructions
|
|
/// uses.
|
|
///
|
|
/// This is the common implementation of the recursive simplification routines.
|
|
/// If we have a pre-simplified value in 'SimpleV', that is forcibly used to
|
|
/// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of
|
|
/// instructions to process and attempt to simplify it using
|
|
/// InstructionSimplify.
|
|
///
|
|
/// This routine returns 'true' only when *it* simplifies something. The passed
|
|
/// in simplified value does not count toward this.
|
|
static bool replaceAndRecursivelySimplifyImpl(Instruction *I, Value *SimpleV,
|
|
const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
bool Simplified = false;
|
|
SmallSetVector<Instruction *, 8> Worklist;
|
|
|
|
// If we have an explicit value to collapse to, do that round of the
|
|
// simplification loop by hand initially.
|
|
if (SimpleV) {
|
|
for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE;
|
|
++UI)
|
|
if (*UI != I)
|
|
Worklist.insert(cast<Instruction>(*UI));
|
|
|
|
// Replace the instruction with its simplified value.
|
|
I->replaceAllUsesWith(SimpleV);
|
|
|
|
// Gracefully handle edge cases where the instruction is not wired into any
|
|
// parent block.
|
|
if (I->getParent())
|
|
I->eraseFromParent();
|
|
} else {
|
|
Worklist.insert(I);
|
|
}
|
|
|
|
// Note that we must test the size on each iteration, the worklist can grow.
|
|
for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) {
|
|
I = Worklist[Idx];
|
|
|
|
// See if this instruction simplifies.
|
|
SimpleV = SimplifyInstruction(I, TD, TLI, DT);
|
|
if (!SimpleV)
|
|
continue;
|
|
|
|
Simplified = true;
|
|
|
|
// Stash away all the uses of the old instruction so we can check them for
|
|
// recursive simplifications after a RAUW. This is cheaper than checking all
|
|
// uses of To on the recursive step in most cases.
|
|
for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE;
|
|
++UI)
|
|
Worklist.insert(cast<Instruction>(*UI));
|
|
|
|
// Replace the instruction with its simplified value.
|
|
I->replaceAllUsesWith(SimpleV);
|
|
|
|
// Gracefully handle edge cases where the instruction is not wired into any
|
|
// parent block.
|
|
if (I->getParent())
|
|
I->eraseFromParent();
|
|
}
|
|
return Simplified;
|
|
}
|
|
|
|
bool llvm::recursivelySimplifyInstruction(Instruction *I,
|
|
const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
return replaceAndRecursivelySimplifyImpl(I, 0, TD, TLI, DT);
|
|
}
|
|
|
|
bool llvm::replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV,
|
|
const DataLayout *TD,
|
|
const TargetLibraryInfo *TLI,
|
|
const DominatorTree *DT) {
|
|
assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!");
|
|
assert(SimpleV && "Must provide a simplified value.");
|
|
return replaceAndRecursivelySimplifyImpl(I, SimpleV, TD, TLI, DT);
|
|
}
|