mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-17 21:29:20 +00:00
pointing this out and correcting the patch! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44907 91177308-0d34-0410-b5e6-96231b3b80d8
743 lines
29 KiB
C++
743 lines
29 KiB
C++
//===-- ConstantFolding.cpp - Analyze constant folding possibilities ------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This family of functions determines the possibility of performing constant
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// folding.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/ConstantFolding.h"
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#include "llvm/Constants.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/Function.h"
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#include "llvm/Instructions.h"
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#include "llvm/Intrinsics.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/StringMap.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Support/GetElementPtrTypeIterator.h"
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#include "llvm/Support/MathExtras.h"
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#include <cerrno>
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#include <cmath>
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using namespace llvm;
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//===----------------------------------------------------------------------===//
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// Constant Folding internal helper functions
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//===----------------------------------------------------------------------===//
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/// IsConstantOffsetFromGlobal - If this constant is actually a constant offset
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/// from a global, return the global and the constant. Because of
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/// constantexprs, this function is recursive.
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static bool IsConstantOffsetFromGlobal(Constant *C, GlobalValue *&GV,
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int64_t &Offset, const TargetData &TD) {
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// Trivial case, constant is the global.
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if ((GV = dyn_cast<GlobalValue>(C))) {
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Offset = 0;
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return true;
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}
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// Otherwise, if this isn't a constant expr, bail out.
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ConstantExpr *CE = dyn_cast<ConstantExpr>(C);
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if (!CE) return false;
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// Look through ptr->int and ptr->ptr casts.
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if (CE->getOpcode() == Instruction::PtrToInt ||
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CE->getOpcode() == Instruction::BitCast)
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return IsConstantOffsetFromGlobal(CE->getOperand(0), GV, Offset, TD);
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// i32* getelementptr ([5 x i32]* @a, i32 0, i32 5)
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if (CE->getOpcode() == Instruction::GetElementPtr) {
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// Cannot compute this if the element type of the pointer is missing size
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// info.
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if (!cast<PointerType>(CE->getOperand(0)->getType())
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->getElementType()->isSized())
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return false;
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// If the base isn't a global+constant, we aren't either.
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if (!IsConstantOffsetFromGlobal(CE->getOperand(0), GV, Offset, TD))
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return false;
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// Otherwise, add any offset that our operands provide.
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gep_type_iterator GTI = gep_type_begin(CE);
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for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i, ++GTI) {
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ConstantInt *CI = dyn_cast<ConstantInt>(CE->getOperand(i));
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if (!CI) return false; // Index isn't a simple constant?
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if (CI->getZExtValue() == 0) continue; // Not adding anything.
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if (const StructType *ST = dyn_cast<StructType>(*GTI)) {
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// N = N + Offset
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Offset += TD.getStructLayout(ST)->getElementOffset(CI->getZExtValue());
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} else {
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const SequentialType *SQT = cast<SequentialType>(*GTI);
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Offset += TD.getABITypeSize(SQT->getElementType())*CI->getSExtValue();
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}
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}
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return true;
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}
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return false;
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}
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/// SymbolicallyEvaluateBinop - One of Op0/Op1 is a constant expression.
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/// Attempt to symbolically evaluate the result of a binary operator merging
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/// these together. If target data info is available, it is provided as TD,
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/// otherwise TD is null.
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static Constant *SymbolicallyEvaluateBinop(unsigned Opc, Constant *Op0,
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Constant *Op1, const TargetData *TD){
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// SROA
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// Fold (and 0xffffffff00000000, (shl x, 32)) -> shl.
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// Fold (lshr (or X, Y), 32) -> (lshr [X/Y], 32) if one doesn't contribute
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// bits.
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// If the constant expr is something like &A[123] - &A[4].f, fold this into a
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// constant. This happens frequently when iterating over a global array.
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if (Opc == Instruction::Sub && TD) {
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GlobalValue *GV1, *GV2;
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int64_t Offs1, Offs2;
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if (IsConstantOffsetFromGlobal(Op0, GV1, Offs1, *TD))
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if (IsConstantOffsetFromGlobal(Op1, GV2, Offs2, *TD) &&
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GV1 == GV2) {
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// (&GV+C1) - (&GV+C2) -> C1-C2, pointer arithmetic cannot overflow.
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return ConstantInt::get(Op0->getType(), Offs1-Offs2);
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}
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}
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// TODO: Fold icmp setne/seteq as well.
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return 0;
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}
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/// SymbolicallyEvaluateGEP - If we can symbolically evaluate the specified GEP
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/// constant expression, do so.
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static Constant *SymbolicallyEvaluateGEP(Constant* const* Ops, unsigned NumOps,
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const Type *ResultTy,
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const TargetData *TD) {
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Constant *Ptr = Ops[0];
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if (!cast<PointerType>(Ptr->getType())->getElementType()->isSized())
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return 0;
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if (TD && Ptr->isNullValue()) {
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// If this is a constant expr gep that is effectively computing an
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// "offsetof", fold it into 'cast int Size to T*' instead of 'gep 0, 0, 12'
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bool isFoldableGEP = true;
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for (unsigned i = 1; i != NumOps; ++i)
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if (!isa<ConstantInt>(Ops[i])) {
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isFoldableGEP = false;
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break;
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}
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if (isFoldableGEP) {
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uint64_t Offset = TD->getIndexedOffset(Ptr->getType(),
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(Value**)Ops+1, NumOps-1);
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Constant *C = ConstantInt::get(TD->getIntPtrType(), Offset);
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return ConstantExpr::getIntToPtr(C, ResultTy);
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}
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}
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return 0;
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}
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/// FoldBitCast - Constant fold bitcast, symbolically evaluating it with
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/// targetdata. Return 0 if unfoldable.
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static Constant *FoldBitCast(Constant *C, const Type *DestTy,
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const TargetData &TD) {
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// If this is a bitcast from constant vector -> vector, fold it.
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if (ConstantVector *CV = dyn_cast<ConstantVector>(C)) {
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if (const VectorType *DestVTy = dyn_cast<VectorType>(DestTy)) {
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// If the element types match, VMCore can fold it.
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unsigned NumDstElt = DestVTy->getNumElements();
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unsigned NumSrcElt = CV->getNumOperands();
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if (NumDstElt == NumSrcElt)
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return 0;
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const Type *SrcEltTy = CV->getType()->getElementType();
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const Type *DstEltTy = DestVTy->getElementType();
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// Otherwise, we're changing the number of elements in a vector, which
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// requires endianness information to do the right thing. For example,
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// bitcast (<2 x i64> <i64 0, i64 1> to <4 x i32>)
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// folds to (little endian):
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// <4 x i32> <i32 0, i32 0, i32 1, i32 0>
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// and to (big endian):
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// <4 x i32> <i32 0, i32 0, i32 0, i32 1>
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// First thing is first. We only want to think about integer here, so if
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// we have something in FP form, recast it as integer.
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if (DstEltTy->isFloatingPoint()) {
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// Fold to an vector of integers with same size as our FP type.
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unsigned FPWidth = DstEltTy->getPrimitiveSizeInBits();
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const Type *DestIVTy = VectorType::get(IntegerType::get(FPWidth),
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NumDstElt);
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// Recursively handle this integer conversion, if possible.
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C = FoldBitCast(C, DestIVTy, TD);
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if (!C) return 0;
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// Finally, VMCore can handle this now that #elts line up.
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return ConstantExpr::getBitCast(C, DestTy);
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}
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// Okay, we know the destination is integer, if the input is FP, convert
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// it to integer first.
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if (SrcEltTy->isFloatingPoint()) {
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unsigned FPWidth = SrcEltTy->getPrimitiveSizeInBits();
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const Type *SrcIVTy = VectorType::get(IntegerType::get(FPWidth),
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NumSrcElt);
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// Ask VMCore to do the conversion now that #elts line up.
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C = ConstantExpr::getBitCast(C, SrcIVTy);
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CV = dyn_cast<ConstantVector>(C);
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if (!CV) return 0; // If VMCore wasn't able to fold it, bail out.
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}
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// Now we know that the input and output vectors are both integer vectors
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// of the same size, and that their #elements is not the same. Do the
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// conversion here, which depends on whether the input or output has
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// more elements.
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bool isLittleEndian = TD.isLittleEndian();
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SmallVector<Constant*, 32> Result;
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if (NumDstElt < NumSrcElt) {
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// Handle: bitcast (<4 x i32> <i32 0, i32 1, i32 2, i32 3> to <2 x i64>)
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Constant *Zero = Constant::getNullValue(DstEltTy);
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unsigned Ratio = NumSrcElt/NumDstElt;
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unsigned SrcBitSize = SrcEltTy->getPrimitiveSizeInBits();
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unsigned SrcElt = 0;
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for (unsigned i = 0; i != NumDstElt; ++i) {
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// Build each element of the result.
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Constant *Elt = Zero;
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unsigned ShiftAmt = isLittleEndian ? 0 : SrcBitSize*(Ratio-1);
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for (unsigned j = 0; j != Ratio; ++j) {
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Constant *Src = dyn_cast<ConstantInt>(CV->getOperand(SrcElt++));
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if (!Src) return 0; // Reject constantexpr elements.
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// Zero extend the element to the right size.
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Src = ConstantExpr::getZExt(Src, Elt->getType());
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// Shift it to the right place, depending on endianness.
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Src = ConstantExpr::getShl(Src,
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ConstantInt::get(Src->getType(), ShiftAmt));
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ShiftAmt += isLittleEndian ? SrcBitSize : -SrcBitSize;
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// Mix it in.
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Elt = ConstantExpr::getOr(Elt, Src);
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}
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Result.push_back(Elt);
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}
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} else {
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// Handle: bitcast (<2 x i64> <i64 0, i64 1> to <4 x i32>)
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unsigned Ratio = NumDstElt/NumSrcElt;
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unsigned DstBitSize = DstEltTy->getPrimitiveSizeInBits();
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// Loop over each source value, expanding into multiple results.
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for (unsigned i = 0; i != NumSrcElt; ++i) {
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Constant *Src = dyn_cast<ConstantInt>(CV->getOperand(i));
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if (!Src) return 0; // Reject constantexpr elements.
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unsigned ShiftAmt = isLittleEndian ? 0 : DstBitSize*(Ratio-1);
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for (unsigned j = 0; j != Ratio; ++j) {
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// Shift the piece of the value into the right place, depending on
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// endianness.
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Constant *Elt = ConstantExpr::getLShr(Src,
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ConstantInt::get(Src->getType(), ShiftAmt));
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ShiftAmt += isLittleEndian ? DstBitSize : -DstBitSize;
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// Truncate and remember this piece.
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Result.push_back(ConstantExpr::getTrunc(Elt, DstEltTy));
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}
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}
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}
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return ConstantVector::get(&Result[0], Result.size());
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}
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}
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return 0;
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}
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//===----------------------------------------------------------------------===//
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// Constant Folding public APIs
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//===----------------------------------------------------------------------===//
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/// ConstantFoldInstruction - Attempt to constant fold the specified
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/// instruction. If successful, the constant result is returned, if not, null
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/// is returned. Note that this function can only fail when attempting to fold
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/// instructions like loads and stores, which have no constant expression form.
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///
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Constant *llvm::ConstantFoldInstruction(Instruction *I, const TargetData *TD) {
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if (PHINode *PN = dyn_cast<PHINode>(I)) {
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if (PN->getNumIncomingValues() == 0)
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return Constant::getNullValue(PN->getType());
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Constant *Result = dyn_cast<Constant>(PN->getIncomingValue(0));
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if (Result == 0) return 0;
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// Handle PHI nodes specially here...
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for (unsigned i = 1, e = PN->getNumIncomingValues(); i != e; ++i)
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if (PN->getIncomingValue(i) != Result && PN->getIncomingValue(i) != PN)
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return 0; // Not all the same incoming constants...
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// If we reach here, all incoming values are the same constant.
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return Result;
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}
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// Scan the operand list, checking to see if they are all constants, if so,
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// hand off to ConstantFoldInstOperands.
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SmallVector<Constant*, 8> Ops;
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for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
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if (Constant *Op = dyn_cast<Constant>(I->getOperand(i)))
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Ops.push_back(Op);
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else
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return 0; // All operands not constant!
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if (const CmpInst *CI = dyn_cast<CmpInst>(I))
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return ConstantFoldCompareInstOperands(CI->getPredicate(),
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&Ops[0], Ops.size(), TD);
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else
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return ConstantFoldInstOperands(I->getOpcode(), I->getType(),
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&Ops[0], Ops.size(), TD);
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}
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/// ConstantFoldInstOperands - Attempt to constant fold an instruction with the
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/// specified opcode and operands. If successful, the constant result is
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/// returned, if not, null is returned. Note that this function can fail when
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/// attempting to fold instructions like loads and stores, which have no
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/// constant expression form.
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///
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Constant *llvm::ConstantFoldInstOperands(unsigned Opcode, const Type *DestTy,
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Constant* const* Ops, unsigned NumOps,
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const TargetData *TD) {
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// Handle easy binops first.
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if (Instruction::isBinaryOp(Opcode)) {
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if (isa<ConstantExpr>(Ops[0]) || isa<ConstantExpr>(Ops[1]))
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if (Constant *C = SymbolicallyEvaluateBinop(Opcode, Ops[0], Ops[1], TD))
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return C;
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return ConstantExpr::get(Opcode, Ops[0], Ops[1]);
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}
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switch (Opcode) {
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default: return 0;
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case Instruction::Call:
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if (Function *F = dyn_cast<Function>(Ops[0]))
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if (canConstantFoldCallTo(F))
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return ConstantFoldCall(F, Ops+1, NumOps-1);
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return 0;
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case Instruction::ICmp:
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case Instruction::FCmp:
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assert(0 &&"This function is invalid for compares: no predicate specified");
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case Instruction::PtrToInt:
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// If the input is a inttoptr, eliminate the pair. This requires knowing
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// the width of a pointer, so it can't be done in ConstantExpr::getCast.
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if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ops[0])) {
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if (TD && CE->getOpcode() == Instruction::IntToPtr) {
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Constant *Input = CE->getOperand(0);
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unsigned InWidth = Input->getType()->getPrimitiveSizeInBits();
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Constant *Mask =
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ConstantInt::get(APInt::getLowBitsSet(InWidth,
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TD->getPointerSizeInBits()));
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Input = ConstantExpr::getAnd(Input, Mask);
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// Do a zext or trunc to get to the dest size.
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return ConstantExpr::getIntegerCast(Input, DestTy, false);
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}
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}
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return ConstantExpr::getCast(Opcode, Ops[0], DestTy);
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case Instruction::IntToPtr:
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case Instruction::Trunc:
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case Instruction::ZExt:
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case Instruction::SExt:
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case Instruction::FPTrunc:
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case Instruction::FPExt:
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case Instruction::UIToFP:
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case Instruction::SIToFP:
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case Instruction::FPToUI:
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case Instruction::FPToSI:
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return ConstantExpr::getCast(Opcode, Ops[0], DestTy);
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case Instruction::BitCast:
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if (TD)
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if (Constant *C = FoldBitCast(Ops[0], DestTy, *TD))
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return C;
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return ConstantExpr::getBitCast(Ops[0], DestTy);
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case Instruction::Select:
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return ConstantExpr::getSelect(Ops[0], Ops[1], Ops[2]);
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case Instruction::ExtractElement:
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return ConstantExpr::getExtractElement(Ops[0], Ops[1]);
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case Instruction::InsertElement:
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return ConstantExpr::getInsertElement(Ops[0], Ops[1], Ops[2]);
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case Instruction::ShuffleVector:
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return ConstantExpr::getShuffleVector(Ops[0], Ops[1], Ops[2]);
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case Instruction::GetElementPtr:
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if (Constant *C = SymbolicallyEvaluateGEP(Ops, NumOps, DestTy, TD))
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return C;
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return ConstantExpr::getGetElementPtr(Ops[0], Ops+1, NumOps-1);
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}
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}
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/// ConstantFoldCompareInstOperands - Attempt to constant fold a compare
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/// instruction (icmp/fcmp) with the specified operands. If it fails, it
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/// returns a constant expression of the specified operands.
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///
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Constant *llvm::ConstantFoldCompareInstOperands(unsigned Predicate,
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Constant*const * Ops,
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unsigned NumOps,
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const TargetData *TD) {
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// fold: icmp (inttoptr x), null -> icmp x, 0
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// fold: icmp (ptrtoint x), 0 -> icmp x, null
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// fold: icmp (inttoptr x), (inttoptr y) -> icmp x, y
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// fold: icmp (ptrtoint x), (ptrtoint y) -> icmp x, y
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//
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// ConstantExpr::getCompare cannot do this, because it doesn't have TD
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// around to know if bit truncation is happening.
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if (ConstantExpr *CE0 = dyn_cast<ConstantExpr>(Ops[0])) {
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if (TD && Ops[1]->isNullValue()) {
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const Type *IntPtrTy = TD->getIntPtrType();
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if (CE0->getOpcode() == Instruction::IntToPtr) {
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// Convert the integer value to the right size to ensure we get the
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// proper extension or truncation.
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Constant *C = ConstantExpr::getIntegerCast(CE0->getOperand(0),
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IntPtrTy, false);
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Constant *NewOps[] = { C, Constant::getNullValue(C->getType()) };
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return ConstantFoldCompareInstOperands(Predicate, NewOps, 2, TD);
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}
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// Only do this transformation if the int is intptrty in size, otherwise
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// there is a truncation or extension that we aren't modeling.
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if (CE0->getOpcode() == Instruction::PtrToInt &&
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CE0->getType() == IntPtrTy) {
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Constant *C = CE0->getOperand(0);
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Constant *NewOps[] = { C, Constant::getNullValue(C->getType()) };
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// FIXME!
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return ConstantFoldCompareInstOperands(Predicate, NewOps, 2, TD);
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}
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}
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if (TD && isa<ConstantExpr>(Ops[1]) &&
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cast<ConstantExpr>(Ops[1])->getOpcode() == CE0->getOpcode()) {
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const Type *IntPtrTy = TD->getIntPtrType();
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// Only do this transformation if the int is intptrty in size, otherwise
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// there is a truncation or extension that we aren't modeling.
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if ((CE0->getOpcode() == Instruction::IntToPtr &&
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CE0->getOperand(0)->getType() == IntPtrTy &&
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Ops[1]->getOperand(0)->getType() == IntPtrTy) ||
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(CE0->getOpcode() == Instruction::PtrToInt &&
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CE0->getType() == IntPtrTy &&
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CE0->getOperand(0)->getType() == Ops[1]->getOperand(0)->getType())) {
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Constant *NewOps[] = {
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CE0->getOperand(0), cast<ConstantExpr>(Ops[1])->getOperand(0)
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};
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return ConstantFoldCompareInstOperands(Predicate, NewOps, 2, TD);
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}
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}
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}
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|
return ConstantExpr::getCompare(Predicate, Ops[0], Ops[1]);
|
|
}
|
|
|
|
|
|
/// ConstantFoldLoadThroughGEPConstantExpr - Given a constant and a
|
|
/// getelementptr constantexpr, return the constant value being addressed by the
|
|
/// constant expression, or null if something is funny and we can't decide.
|
|
Constant *llvm::ConstantFoldLoadThroughGEPConstantExpr(Constant *C,
|
|
ConstantExpr *CE) {
|
|
if (CE->getOperand(1) != Constant::getNullValue(CE->getOperand(1)->getType()))
|
|
return 0; // Do not allow stepping over the value!
|
|
|
|
// Loop over all of the operands, tracking down which value we are
|
|
// addressing...
|
|
gep_type_iterator I = gep_type_begin(CE), E = gep_type_end(CE);
|
|
for (++I; I != E; ++I)
|
|
if (const StructType *STy = dyn_cast<StructType>(*I)) {
|
|
ConstantInt *CU = cast<ConstantInt>(I.getOperand());
|
|
assert(CU->getZExtValue() < STy->getNumElements() &&
|
|
"Struct index out of range!");
|
|
unsigned El = (unsigned)CU->getZExtValue();
|
|
if (ConstantStruct *CS = dyn_cast<ConstantStruct>(C)) {
|
|
C = CS->getOperand(El);
|
|
} else if (isa<ConstantAggregateZero>(C)) {
|
|
C = Constant::getNullValue(STy->getElementType(El));
|
|
} else if (isa<UndefValue>(C)) {
|
|
C = UndefValue::get(STy->getElementType(El));
|
|
} else {
|
|
return 0;
|
|
}
|
|
} else if (ConstantInt *CI = dyn_cast<ConstantInt>(I.getOperand())) {
|
|
if (const ArrayType *ATy = dyn_cast<ArrayType>(*I)) {
|
|
if (CI->getZExtValue() >= ATy->getNumElements())
|
|
return 0;
|
|
if (ConstantArray *CA = dyn_cast<ConstantArray>(C))
|
|
C = CA->getOperand(CI->getZExtValue());
|
|
else if (isa<ConstantAggregateZero>(C))
|
|
C = Constant::getNullValue(ATy->getElementType());
|
|
else if (isa<UndefValue>(C))
|
|
C = UndefValue::get(ATy->getElementType());
|
|
else
|
|
return 0;
|
|
} else if (const VectorType *PTy = dyn_cast<VectorType>(*I)) {
|
|
if (CI->getZExtValue() >= PTy->getNumElements())
|
|
return 0;
|
|
if (ConstantVector *CP = dyn_cast<ConstantVector>(C))
|
|
C = CP->getOperand(CI->getZExtValue());
|
|
else if (isa<ConstantAggregateZero>(C))
|
|
C = Constant::getNullValue(PTy->getElementType());
|
|
else if (isa<UndefValue>(C))
|
|
C = UndefValue::get(PTy->getElementType());
|
|
else
|
|
return 0;
|
|
} else {
|
|
return 0;
|
|
}
|
|
} else {
|
|
return 0;
|
|
}
|
|
return C;
|
|
}
|
|
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Constant Folding for Calls
|
|
//
|
|
|
|
/// canConstantFoldCallTo - Return true if its even possible to fold a call to
|
|
/// the specified function.
|
|
bool
|
|
llvm::canConstantFoldCallTo(Function *F) {
|
|
switch (F->getIntrinsicID()) {
|
|
case Intrinsic::sqrt:
|
|
case Intrinsic::powi:
|
|
case Intrinsic::bswap:
|
|
case Intrinsic::ctpop:
|
|
case Intrinsic::ctlz:
|
|
case Intrinsic::cttz:
|
|
return true;
|
|
default: break;
|
|
}
|
|
|
|
const ValueName *NameVal = F->getValueName();
|
|
if (NameVal == 0) return false;
|
|
const char *Str = NameVal->getKeyData();
|
|
unsigned Len = NameVal->getKeyLength();
|
|
|
|
// In these cases, the check of the length is required. We don't want to
|
|
// return true for a name like "cos\0blah" which strcmp would return equal to
|
|
// "cos", but has length 8.
|
|
switch (Str[0]) {
|
|
default: return false;
|
|
case 'a':
|
|
if (Len == 4)
|
|
return !strcmp(Str, "acos") || !strcmp(Str, "asin") ||
|
|
!strcmp(Str, "atan");
|
|
else if (Len == 5)
|
|
return !strcmp(Str, "atan2");
|
|
return false;
|
|
case 'c':
|
|
if (Len == 3)
|
|
return !strcmp(Str, "cos");
|
|
else if (Len == 4)
|
|
return !strcmp(Str, "ceil") || !strcmp(Str, "cosf") ||
|
|
!strcmp(Str, "cosh");
|
|
return false;
|
|
case 'e':
|
|
if (Len == 3)
|
|
return !strcmp(Str, "exp");
|
|
return false;
|
|
case 'f':
|
|
if (Len == 4)
|
|
return !strcmp(Str, "fabs") || !strcmp(Str, "fmod");
|
|
else if (Len == 5)
|
|
return !strcmp(Str, "floor");
|
|
return false;
|
|
break;
|
|
case 'l':
|
|
if (Len == 3 && !strcmp(Str, "log"))
|
|
return true;
|
|
if (Len == 5 && !strcmp(Str, "log10"))
|
|
return true;
|
|
return false;
|
|
case 'p':
|
|
if (Len == 3 && !strcmp(Str, "pow"))
|
|
return true;
|
|
return false;
|
|
case 's':
|
|
if (Len == 3)
|
|
return !strcmp(Str, "sin");
|
|
if (Len == 4)
|
|
return !strcmp(Str, "sinh") || !strcmp(Str, "sqrt");
|
|
if (Len == 5)
|
|
return !strcmp(Str, "sqrtf");
|
|
return false;
|
|
case 't':
|
|
if (Len == 3 && !strcmp(Str, "tan"))
|
|
return true;
|
|
else if (Len == 4 && !strcmp(Str, "tanh"))
|
|
return true;
|
|
return false;
|
|
}
|
|
}
|
|
|
|
static Constant *ConstantFoldFP(double (*NativeFP)(double), double V,
|
|
const Type *Ty) {
|
|
errno = 0;
|
|
V = NativeFP(V);
|
|
if (errno == 0) {
|
|
if (Ty==Type::FloatTy)
|
|
return ConstantFP::get(Ty, APFloat((float)V));
|
|
else if (Ty==Type::DoubleTy)
|
|
return ConstantFP::get(Ty, APFloat(V));
|
|
else
|
|
assert(0);
|
|
}
|
|
errno = 0;
|
|
return 0;
|
|
}
|
|
|
|
static Constant *ConstantFoldBinaryFP(double (*NativeFP)(double, double),
|
|
double V, double W,
|
|
const Type *Ty) {
|
|
errno = 0;
|
|
V = NativeFP(V, W);
|
|
if (errno == 0) {
|
|
if (Ty==Type::FloatTy)
|
|
return ConstantFP::get(Ty, APFloat((float)V));
|
|
else if (Ty==Type::DoubleTy)
|
|
return ConstantFP::get(Ty, APFloat(V));
|
|
else
|
|
assert(0);
|
|
}
|
|
errno = 0;
|
|
return 0;
|
|
}
|
|
|
|
/// ConstantFoldCall - Attempt to constant fold a call to the specified function
|
|
/// with the specified arguments, returning null if unsuccessful.
|
|
|
|
Constant *
|
|
llvm::ConstantFoldCall(Function *F,
|
|
Constant* const* Operands, unsigned NumOperands) {
|
|
const ValueName *NameVal = F->getValueName();
|
|
if (NameVal == 0) return 0;
|
|
const char *Str = NameVal->getKeyData();
|
|
unsigned Len = NameVal->getKeyLength();
|
|
|
|
const Type *Ty = F->getReturnType();
|
|
if (NumOperands == 1) {
|
|
if (ConstantFP *Op = dyn_cast<ConstantFP>(Operands[0])) {
|
|
if (Ty!=Type::FloatTy && Ty!=Type::DoubleTy)
|
|
return 0;
|
|
/// Currently APFloat versions of these functions do not exist, so we use
|
|
/// the host native double versions. Float versions are not called
|
|
/// directly but for all these it is true (float)(f((double)arg)) ==
|
|
/// f(arg). Long double not supported yet.
|
|
double V = Ty==Type::FloatTy ? (double)Op->getValueAPF().convertToFloat():
|
|
Op->getValueAPF().convertToDouble();
|
|
switch (Str[0]) {
|
|
case 'a':
|
|
if (Len == 4 && !strcmp(Str, "acos"))
|
|
return ConstantFoldFP(acos, V, Ty);
|
|
else if (Len == 4 && !strcmp(Str, "asin"))
|
|
return ConstantFoldFP(asin, V, Ty);
|
|
else if (Len == 4 && !strcmp(Str, "atan"))
|
|
return ConstantFoldFP(atan, V, Ty);
|
|
break;
|
|
case 'c':
|
|
if (Len == 4 && !strcmp(Str, "ceil"))
|
|
return ConstantFoldFP(ceil, V, Ty);
|
|
else if (Len == 3 && !strcmp(Str, "cos"))
|
|
return ConstantFoldFP(cos, V, Ty);
|
|
else if (Len == 4 && !strcmp(Str, "cosh"))
|
|
return ConstantFoldFP(cosh, V, Ty);
|
|
break;
|
|
case 'e':
|
|
if (Len == 3 && !strcmp(Str, "exp"))
|
|
return ConstantFoldFP(exp, V, Ty);
|
|
break;
|
|
case 'f':
|
|
if (Len == 4 && !strcmp(Str, "fabs"))
|
|
return ConstantFoldFP(fabs, V, Ty);
|
|
else if (Len == 5 && !strcmp(Str, "floor"))
|
|
return ConstantFoldFP(floor, V, Ty);
|
|
break;
|
|
case 'l':
|
|
if (Len == 3 && !strcmp(Str, "log") && V > 0)
|
|
return ConstantFoldFP(log, V, Ty);
|
|
else if (Len == 5 && !strcmp(Str, "log10") && V > 0)
|
|
return ConstantFoldFP(log10, V, Ty);
|
|
else if (!strcmp(Str, "llvm.sqrt.f32") ||
|
|
!strcmp(Str, "llvm.sqrt.f64")) {
|
|
if (V >= -0.0)
|
|
return ConstantFoldFP(sqrt, V, Ty);
|
|
else // Undefined
|
|
return ConstantFP::get(Ty, Ty==Type::FloatTy ? APFloat(0.0f) :
|
|
APFloat(0.0));
|
|
}
|
|
break;
|
|
case 's':
|
|
if (Len == 3 && !strcmp(Str, "sin"))
|
|
return ConstantFoldFP(sin, V, Ty);
|
|
else if (Len == 4 && !strcmp(Str, "sinh"))
|
|
return ConstantFoldFP(sinh, V, Ty);
|
|
else if (Len == 4 && !strcmp(Str, "sqrt") && V >= 0)
|
|
return ConstantFoldFP(sqrt, V, Ty);
|
|
else if (Len == 5 && !strcmp(Str, "sqrtf") && V >= 0)
|
|
return ConstantFoldFP(sqrt, V, Ty);
|
|
break;
|
|
case 't':
|
|
if (Len == 3 && !strcmp(Str, "tan"))
|
|
return ConstantFoldFP(tan, V, Ty);
|
|
else if (Len == 4 && !strcmp(Str, "tanh"))
|
|
return ConstantFoldFP(tanh, V, Ty);
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
} else if (ConstantInt *Op = dyn_cast<ConstantInt>(Operands[0])) {
|
|
if (Len > 11 && !memcmp(Str, "llvm.bswap", 10))
|
|
return ConstantInt::get(Op->getValue().byteSwap());
|
|
else if (Len > 11 && !memcmp(Str, "llvm.ctpop", 10))
|
|
return ConstantInt::get(Ty, Op->getValue().countPopulation());
|
|
else if (Len > 10 && !memcmp(Str, "llvm.cttz", 9))
|
|
return ConstantInt::get(Ty, Op->getValue().countTrailingZeros());
|
|
else if (Len > 10 && !memcmp(Str, "llvm.ctlz", 9))
|
|
return ConstantInt::get(Ty, Op->getValue().countLeadingZeros());
|
|
}
|
|
} else if (NumOperands == 2) {
|
|
if (ConstantFP *Op1 = dyn_cast<ConstantFP>(Operands[0])) {
|
|
if (Ty!=Type::FloatTy && Ty!=Type::DoubleTy)
|
|
return 0;
|
|
double Op1V = Ty==Type::FloatTy ?
|
|
(double)Op1->getValueAPF().convertToFloat():
|
|
Op1->getValueAPF().convertToDouble();
|
|
if (ConstantFP *Op2 = dyn_cast<ConstantFP>(Operands[1])) {
|
|
double Op2V = Ty==Type::FloatTy ?
|
|
(double)Op2->getValueAPF().convertToFloat():
|
|
Op2->getValueAPF().convertToDouble();
|
|
|
|
if (Len == 3 && !strcmp(Str, "pow")) {
|
|
return ConstantFoldBinaryFP(pow, Op1V, Op2V, Ty);
|
|
} else if (Len == 4 && !strcmp(Str, "fmod")) {
|
|
return ConstantFoldBinaryFP(fmod, Op1V, Op2V, Ty);
|
|
} else if (Len == 5 && !strcmp(Str, "atan2")) {
|
|
return ConstantFoldBinaryFP(atan2, Op1V, Op2V, Ty);
|
|
}
|
|
} else if (ConstantInt *Op2C = dyn_cast<ConstantInt>(Operands[1])) {
|
|
if (!strcmp(Str, "llvm.powi.f32")) {
|
|
return ConstantFP::get(Ty, APFloat((float)std::pow((float)Op1V,
|
|
(int)Op2C->getZExtValue())));
|
|
} else if (!strcmp(Str, "llvm.powi.f64")) {
|
|
return ConstantFP::get(Ty, APFloat((double)std::pow((double)Op1V,
|
|
(int)Op2C->getZExtValue())));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|