mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-13 23:29:27 +00:00
6b980541df
bit simpler by handling a common case explicitly. Also, refactor the implementation to use a worklist based walk of the recursive users, rather than trying to use value handles to detect and recover from RAUWs during the recursive descent. This fixes a very subtle bug in the previous implementation where degenerate control flow structures could cause mutually recursive instructions (PHI nodes) to collapse in just such a way that From became equal to To after some amount of recursion. At that point, we hit the inf-loop that the assert at the top attempted to guard against. This problem is defined away when not using value handles in this manner. There are lots of comments claiming that the WeakVH will protect against just this sort of error, but they're not accurate about the actual implementation of WeakVHs, which do still track RAUWs. I don't have any test case for the bug this fixes because it requires running the recursive simplification on unreachable phi nodes. I've no way to either run this or easily write an input that triggers it. It was found when using instruction simplification inside the inliner when running over the nightly test-suite. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153393 91177308-0d34-0410-b5e6-96231b3b80d8
219 lines
10 KiB
C++
219 lines
10 KiB
C++
//===-- InstructionSimplify.h - Fold instructions into simpler forms ------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file declares routines for folding instructions into simpler forms
|
|
// that do not require creating new instructions. This does constant folding
|
|
// ("add i32 1, 1" -> "2") but can also handle non-constant operands, either
|
|
// returning a constant ("and i32 %x, 0" -> "0") or an already existing value
|
|
// ("and i32 %x, %x" -> "%x"). If the simplification is also an instruction
|
|
// then it dominates the original instruction.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_ANALYSIS_INSTRUCTIONSIMPLIFY_H
|
|
#define LLVM_ANALYSIS_INSTRUCTIONSIMPLIFY_H
|
|
|
|
namespace llvm {
|
|
template<typename T>
|
|
class ArrayRef;
|
|
class DominatorTree;
|
|
class Instruction;
|
|
class TargetData;
|
|
class TargetLibraryInfo;
|
|
class Type;
|
|
class Value;
|
|
|
|
/// SimplifyAddInst - Given operands for an Add, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
Value *SimplifyAddInst(Value *LHS, Value *RHS, bool isNSW, bool isNUW,
|
|
const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifySubInst - Given operands for a Sub, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
Value *SimplifySubInst(Value *LHS, Value *RHS, bool isNSW, bool isNUW,
|
|
const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifyMulInst - Given operands for a Mul, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
Value *SimplifyMulInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifySDivInst - Given operands for an SDiv, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
Value *SimplifySDivInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifyUDivInst - Given operands for a UDiv, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
Value *SimplifyUDivInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifyFDivInst - Given operands for an FDiv, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
Value *SimplifyFDivInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifySRemInst - Given operands for an SRem, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
Value *SimplifySRemInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifyURemInst - Given operands for a URem, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
Value *SimplifyURemInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifyFRemInst - Given operands for an FRem, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
Value *SimplifyFRemInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifyShlInst - Given operands for a Shl, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
|
|
const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifyLShrInst - Given operands for a LShr, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
|
|
const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifyAShrInst - Given operands for a AShr, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
|
|
const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifyAndInst - Given operands for an And, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
Value *SimplifyAndInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifyOrInst - Given operands for an Or, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
Value *SimplifyOrInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifyXorInst - Given operands for a Xor, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
Value *SimplifyXorInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
|
|
const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
|
|
const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifySelectInst - Given operands for a SelectInst, see if we can fold
|
|
/// the result. If not, this returns null.
|
|
Value *SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
|
|
const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we
|
|
/// can fold the result. If not, this returns null.
|
|
Value *SimplifyInsertValueInst(Value *Agg, Value *Val,
|
|
ArrayRef<unsigned> Idxs,
|
|
const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifyTruncInst - Given operands for an TruncInst, see if we can fold
|
|
/// the result. If not, this returns null.
|
|
Value *SimplifyTruncInst(Value *Op, Type *Ty, const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
//=== Helper functions for higher up the class hierarchy.
|
|
|
|
|
|
/// SimplifyCmpInst - Given operands for a CmpInst, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
|
|
const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
|
|
/// fold the result. If not, this returns null.
|
|
Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
|
|
const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// SimplifyInstruction - See if we can compute a simplified version of this
|
|
/// instruction. If not, this returns null.
|
|
Value *SimplifyInstruction(Instruction *I, const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
|
|
/// \brief Replace all uses of 'I' with 'SimpleV' and simplify the uses
|
|
/// recursively.
|
|
///
|
|
/// This first performs a normal RAUW of I with SimpleV. It then recursively
|
|
/// attempts to simplify those users updated by the operation. The 'I'
|
|
/// instruction must not be equal to the simplified value 'SimpleV'.
|
|
///
|
|
/// The function returns true if any simplifications were performed.
|
|
bool replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV,
|
|
const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
|
|
/// \brief Recursively attempt to simplify an instruction.
|
|
///
|
|
/// This routine uses SimplifyInstruction to simplify 'I', and if successful
|
|
/// replaces uses of 'I' with the simplified value. It then recurses on each
|
|
/// of the users impacted. It returns true if any simplifications were
|
|
/// performed.
|
|
bool recursivelySimplifyInstruction(Instruction *I,
|
|
const TargetData *TD = 0,
|
|
const TargetLibraryInfo *TLI = 0,
|
|
const DominatorTree *DT = 0);
|
|
} // end namespace llvm
|
|
|
|
#endif
|
|
|