mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2025-10-31 08:16:47 +00:00
5f23a938b0
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108736 91177308-0d34-0410-b5e6-96231b3b80d8
1449 lines
59 KiB
C++
1449 lines
59 KiB
C++
//===- InstCombineCasts.cpp -----------------------------------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements the visit functions for cast operations.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "InstCombine.h"
|
|
#include "llvm/Target/TargetData.h"
|
|
#include "llvm/Support/PatternMatch.h"
|
|
using namespace llvm;
|
|
using namespace PatternMatch;
|
|
|
|
/// DecomposeSimpleLinearExpr - Analyze 'Val', seeing if it is a simple linear
|
|
/// expression. If so, decompose it, returning some value X, such that Val is
|
|
/// X*Scale+Offset.
|
|
///
|
|
static Value *DecomposeSimpleLinearExpr(Value *Val, unsigned &Scale,
|
|
uint64_t &Offset) {
|
|
if (ConstantInt *CI = dyn_cast<ConstantInt>(Val)) {
|
|
Offset = CI->getZExtValue();
|
|
Scale = 0;
|
|
return ConstantInt::get(Val->getType(), 0);
|
|
}
|
|
|
|
if (BinaryOperator *I = dyn_cast<BinaryOperator>(Val)) {
|
|
if (ConstantInt *RHS = dyn_cast<ConstantInt>(I->getOperand(1))) {
|
|
if (I->getOpcode() == Instruction::Shl) {
|
|
// This is a value scaled by '1 << the shift amt'.
|
|
Scale = UINT64_C(1) << RHS->getZExtValue();
|
|
Offset = 0;
|
|
return I->getOperand(0);
|
|
}
|
|
|
|
if (I->getOpcode() == Instruction::Mul) {
|
|
// This value is scaled by 'RHS'.
|
|
Scale = RHS->getZExtValue();
|
|
Offset = 0;
|
|
return I->getOperand(0);
|
|
}
|
|
|
|
if (I->getOpcode() == Instruction::Add) {
|
|
// We have X+C. Check to see if we really have (X*C2)+C1,
|
|
// where C1 is divisible by C2.
|
|
unsigned SubScale;
|
|
Value *SubVal =
|
|
DecomposeSimpleLinearExpr(I->getOperand(0), SubScale, Offset);
|
|
Offset += RHS->getZExtValue();
|
|
Scale = SubScale;
|
|
return SubVal;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Otherwise, we can't look past this.
|
|
Scale = 1;
|
|
Offset = 0;
|
|
return Val;
|
|
}
|
|
|
|
/// PromoteCastOfAllocation - If we find a cast of an allocation instruction,
|
|
/// try to eliminate the cast by moving the type information into the alloc.
|
|
Instruction *InstCombiner::PromoteCastOfAllocation(BitCastInst &CI,
|
|
AllocaInst &AI) {
|
|
// This requires TargetData to get the alloca alignment and size information.
|
|
if (!TD) return 0;
|
|
|
|
const PointerType *PTy = cast<PointerType>(CI.getType());
|
|
|
|
BuilderTy AllocaBuilder(*Builder);
|
|
AllocaBuilder.SetInsertPoint(AI.getParent(), &AI);
|
|
|
|
// Get the type really allocated and the type casted to.
|
|
const Type *AllocElTy = AI.getAllocatedType();
|
|
const Type *CastElTy = PTy->getElementType();
|
|
if (!AllocElTy->isSized() || !CastElTy->isSized()) return 0;
|
|
|
|
unsigned AllocElTyAlign = TD->getABITypeAlignment(AllocElTy);
|
|
unsigned CastElTyAlign = TD->getABITypeAlignment(CastElTy);
|
|
if (CastElTyAlign < AllocElTyAlign) return 0;
|
|
|
|
// If the allocation has multiple uses, only promote it if we are strictly
|
|
// increasing the alignment of the resultant allocation. If we keep it the
|
|
// same, we open the door to infinite loops of various kinds. (A reference
|
|
// from a dbg.declare doesn't count as a use for this purpose.)
|
|
if (!AI.hasOneUse() && !hasOneUsePlusDeclare(&AI) &&
|
|
CastElTyAlign == AllocElTyAlign) return 0;
|
|
|
|
uint64_t AllocElTySize = TD->getTypeAllocSize(AllocElTy);
|
|
uint64_t CastElTySize = TD->getTypeAllocSize(CastElTy);
|
|
if (CastElTySize == 0 || AllocElTySize == 0) return 0;
|
|
|
|
// See if we can satisfy the modulus by pulling a scale out of the array
|
|
// size argument.
|
|
unsigned ArraySizeScale;
|
|
uint64_t ArrayOffset;
|
|
Value *NumElements = // See if the array size is a decomposable linear expr.
|
|
DecomposeSimpleLinearExpr(AI.getOperand(0), ArraySizeScale, ArrayOffset);
|
|
|
|
// If we can now satisfy the modulus, by using a non-1 scale, we really can
|
|
// do the xform.
|
|
if ((AllocElTySize*ArraySizeScale) % CastElTySize != 0 ||
|
|
(AllocElTySize*ArrayOffset ) % CastElTySize != 0) return 0;
|
|
|
|
unsigned Scale = (AllocElTySize*ArraySizeScale)/CastElTySize;
|
|
Value *Amt = 0;
|
|
if (Scale == 1) {
|
|
Amt = NumElements;
|
|
} else {
|
|
Amt = ConstantInt::get(AI.getArraySize()->getType(), Scale);
|
|
// Insert before the alloca, not before the cast.
|
|
Amt = AllocaBuilder.CreateMul(Amt, NumElements, "tmp");
|
|
}
|
|
|
|
if (uint64_t Offset = (AllocElTySize*ArrayOffset)/CastElTySize) {
|
|
Value *Off = ConstantInt::get(AI.getArraySize()->getType(),
|
|
Offset, true);
|
|
Amt = AllocaBuilder.CreateAdd(Amt, Off, "tmp");
|
|
}
|
|
|
|
AllocaInst *New = AllocaBuilder.CreateAlloca(CastElTy, Amt);
|
|
New->setAlignment(AI.getAlignment());
|
|
New->takeName(&AI);
|
|
|
|
// If the allocation has one real use plus a dbg.declare, just remove the
|
|
// declare.
|
|
if (DbgDeclareInst *DI = hasOneUsePlusDeclare(&AI)) {
|
|
EraseInstFromFunction(*(Instruction*)DI);
|
|
}
|
|
// If the allocation has multiple real uses, insert a cast and change all
|
|
// things that used it to use the new cast. This will also hack on CI, but it
|
|
// will die soon.
|
|
else if (!AI.hasOneUse()) {
|
|
// New is the allocation instruction, pointer typed. AI is the original
|
|
// allocation instruction, also pointer typed. Thus, cast to use is BitCast.
|
|
Value *NewCast = AllocaBuilder.CreateBitCast(New, AI.getType(), "tmpcast");
|
|
AI.replaceAllUsesWith(NewCast);
|
|
}
|
|
return ReplaceInstUsesWith(CI, New);
|
|
}
|
|
|
|
|
|
|
|
/// EvaluateInDifferentType - Given an expression that
|
|
/// CanEvaluateTruncated or CanEvaluateSExtd returns true for, actually
|
|
/// insert the code to evaluate the expression.
|
|
Value *InstCombiner::EvaluateInDifferentType(Value *V, const Type *Ty,
|
|
bool isSigned) {
|
|
if (Constant *C = dyn_cast<Constant>(V)) {
|
|
C = ConstantExpr::getIntegerCast(C, Ty, isSigned /*Sext or ZExt*/);
|
|
// If we got a constantexpr back, try to simplify it with TD info.
|
|
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
|
|
C = ConstantFoldConstantExpression(CE, TD);
|
|
return C;
|
|
}
|
|
|
|
// Otherwise, it must be an instruction.
|
|
Instruction *I = cast<Instruction>(V);
|
|
Instruction *Res = 0;
|
|
unsigned Opc = I->getOpcode();
|
|
switch (Opc) {
|
|
case Instruction::Add:
|
|
case Instruction::Sub:
|
|
case Instruction::Mul:
|
|
case Instruction::And:
|
|
case Instruction::Or:
|
|
case Instruction::Xor:
|
|
case Instruction::AShr:
|
|
case Instruction::LShr:
|
|
case Instruction::Shl:
|
|
case Instruction::UDiv:
|
|
case Instruction::URem: {
|
|
Value *LHS = EvaluateInDifferentType(I->getOperand(0), Ty, isSigned);
|
|
Value *RHS = EvaluateInDifferentType(I->getOperand(1), Ty, isSigned);
|
|
Res = BinaryOperator::Create((Instruction::BinaryOps)Opc, LHS, RHS);
|
|
break;
|
|
}
|
|
case Instruction::Trunc:
|
|
case Instruction::ZExt:
|
|
case Instruction::SExt:
|
|
// If the source type of the cast is the type we're trying for then we can
|
|
// just return the source. There's no need to insert it because it is not
|
|
// new.
|
|
if (I->getOperand(0)->getType() == Ty)
|
|
return I->getOperand(0);
|
|
|
|
// Otherwise, must be the same type of cast, so just reinsert a new one.
|
|
// This also handles the case of zext(trunc(x)) -> zext(x).
|
|
Res = CastInst::CreateIntegerCast(I->getOperand(0), Ty,
|
|
Opc == Instruction::SExt);
|
|
break;
|
|
case Instruction::Select: {
|
|
Value *True = EvaluateInDifferentType(I->getOperand(1), Ty, isSigned);
|
|
Value *False = EvaluateInDifferentType(I->getOperand(2), Ty, isSigned);
|
|
Res = SelectInst::Create(I->getOperand(0), True, False);
|
|
break;
|
|
}
|
|
case Instruction::PHI: {
|
|
PHINode *OPN = cast<PHINode>(I);
|
|
PHINode *NPN = PHINode::Create(Ty);
|
|
for (unsigned i = 0, e = OPN->getNumIncomingValues(); i != e; ++i) {
|
|
Value *V =EvaluateInDifferentType(OPN->getIncomingValue(i), Ty, isSigned);
|
|
NPN->addIncoming(V, OPN->getIncomingBlock(i));
|
|
}
|
|
Res = NPN;
|
|
break;
|
|
}
|
|
default:
|
|
// TODO: Can handle more cases here.
|
|
llvm_unreachable("Unreachable!");
|
|
break;
|
|
}
|
|
|
|
Res->takeName(I);
|
|
return InsertNewInstBefore(Res, *I);
|
|
}
|
|
|
|
|
|
/// This function is a wrapper around CastInst::isEliminableCastPair. It
|
|
/// simply extracts arguments and returns what that function returns.
|
|
static Instruction::CastOps
|
|
isEliminableCastPair(
|
|
const CastInst *CI, ///< The first cast instruction
|
|
unsigned opcode, ///< The opcode of the second cast instruction
|
|
const Type *DstTy, ///< The target type for the second cast instruction
|
|
TargetData *TD ///< The target data for pointer size
|
|
) {
|
|
|
|
const Type *SrcTy = CI->getOperand(0)->getType(); // A from above
|
|
const Type *MidTy = CI->getType(); // B from above
|
|
|
|
// Get the opcodes of the two Cast instructions
|
|
Instruction::CastOps firstOp = Instruction::CastOps(CI->getOpcode());
|
|
Instruction::CastOps secondOp = Instruction::CastOps(opcode);
|
|
|
|
unsigned Res = CastInst::isEliminableCastPair(firstOp, secondOp, SrcTy, MidTy,
|
|
DstTy,
|
|
TD ? TD->getIntPtrType(CI->getContext()) : 0);
|
|
|
|
// We don't want to form an inttoptr or ptrtoint that converts to an integer
|
|
// type that differs from the pointer size.
|
|
if ((Res == Instruction::IntToPtr &&
|
|
(!TD || SrcTy != TD->getIntPtrType(CI->getContext()))) ||
|
|
(Res == Instruction::PtrToInt &&
|
|
(!TD || DstTy != TD->getIntPtrType(CI->getContext()))))
|
|
Res = 0;
|
|
|
|
return Instruction::CastOps(Res);
|
|
}
|
|
|
|
/// ShouldOptimizeCast - Return true if the cast from "V to Ty" actually
|
|
/// results in any code being generated and is interesting to optimize out. If
|
|
/// the cast can be eliminated by some other simple transformation, we prefer
|
|
/// to do the simplification first.
|
|
bool InstCombiner::ShouldOptimizeCast(Instruction::CastOps opc, const Value *V,
|
|
const Type *Ty) {
|
|
// Noop casts and casts of constants should be eliminated trivially.
|
|
if (V->getType() == Ty || isa<Constant>(V)) return false;
|
|
|
|
// If this is another cast that can be eliminated, we prefer to have it
|
|
// eliminated.
|
|
if (const CastInst *CI = dyn_cast<CastInst>(V))
|
|
if (isEliminableCastPair(CI, opc, Ty, TD))
|
|
return false;
|
|
|
|
// If this is a vector sext from a compare, then we don't want to break the
|
|
// idiom where each element of the extended vector is either zero or all ones.
|
|
if (opc == Instruction::SExt && isa<CmpInst>(V) && Ty->isVectorTy())
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
/// @brief Implement the transforms common to all CastInst visitors.
|
|
Instruction *InstCombiner::commonCastTransforms(CastInst &CI) {
|
|
Value *Src = CI.getOperand(0);
|
|
|
|
// Many cases of "cast of a cast" are eliminable. If it's eliminable we just
|
|
// eliminate it now.
|
|
if (CastInst *CSrc = dyn_cast<CastInst>(Src)) { // A->B->C cast
|
|
if (Instruction::CastOps opc =
|
|
isEliminableCastPair(CSrc, CI.getOpcode(), CI.getType(), TD)) {
|
|
// The first cast (CSrc) is eliminable so we need to fix up or replace
|
|
// the second cast (CI). CSrc will then have a good chance of being dead.
|
|
return CastInst::Create(opc, CSrc->getOperand(0), CI.getType());
|
|
}
|
|
}
|
|
|
|
// If we are casting a select then fold the cast into the select
|
|
if (SelectInst *SI = dyn_cast<SelectInst>(Src))
|
|
if (Instruction *NV = FoldOpIntoSelect(CI, SI))
|
|
return NV;
|
|
|
|
// If we are casting a PHI then fold the cast into the PHI
|
|
if (isa<PHINode>(Src)) {
|
|
// We don't do this if this would create a PHI node with an illegal type if
|
|
// it is currently legal.
|
|
if (!Src->getType()->isIntegerTy() ||
|
|
!CI.getType()->isIntegerTy() ||
|
|
ShouldChangeType(CI.getType(), Src->getType()))
|
|
if (Instruction *NV = FoldOpIntoPhi(CI))
|
|
return NV;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/// CanEvaluateTruncated - Return true if we can evaluate the specified
|
|
/// expression tree as type Ty instead of its larger type, and arrive with the
|
|
/// same value. This is used by code that tries to eliminate truncates.
|
|
///
|
|
/// Ty will always be a type smaller than V. We should return true if trunc(V)
|
|
/// can be computed by computing V in the smaller type. If V is an instruction,
|
|
/// then trunc(inst(x,y)) can be computed as inst(trunc(x),trunc(y)), which only
|
|
/// makes sense if x and y can be efficiently truncated.
|
|
///
|
|
/// This function works on both vectors and scalars.
|
|
///
|
|
static bool CanEvaluateTruncated(Value *V, const Type *Ty) {
|
|
// We can always evaluate constants in another type.
|
|
if (isa<Constant>(V))
|
|
return true;
|
|
|
|
Instruction *I = dyn_cast<Instruction>(V);
|
|
if (!I) return false;
|
|
|
|
const Type *OrigTy = V->getType();
|
|
|
|
// If this is an extension from the dest type, we can eliminate it, even if it
|
|
// has multiple uses.
|
|
if ((isa<ZExtInst>(I) || isa<SExtInst>(I)) &&
|
|
I->getOperand(0)->getType() == Ty)
|
|
return true;
|
|
|
|
// We can't extend or shrink something that has multiple uses: doing so would
|
|
// require duplicating the instruction in general, which isn't profitable.
|
|
if (!I->hasOneUse()) return false;
|
|
|
|
unsigned Opc = I->getOpcode();
|
|
switch (Opc) {
|
|
case Instruction::Add:
|
|
case Instruction::Sub:
|
|
case Instruction::Mul:
|
|
case Instruction::And:
|
|
case Instruction::Or:
|
|
case Instruction::Xor:
|
|
// These operators can all arbitrarily be extended or truncated.
|
|
return CanEvaluateTruncated(I->getOperand(0), Ty) &&
|
|
CanEvaluateTruncated(I->getOperand(1), Ty);
|
|
|
|
case Instruction::UDiv:
|
|
case Instruction::URem: {
|
|
// UDiv and URem can be truncated if all the truncated bits are zero.
|
|
uint32_t OrigBitWidth = OrigTy->getScalarSizeInBits();
|
|
uint32_t BitWidth = Ty->getScalarSizeInBits();
|
|
if (BitWidth < OrigBitWidth) {
|
|
APInt Mask = APInt::getHighBitsSet(OrigBitWidth, OrigBitWidth-BitWidth);
|
|
if (MaskedValueIsZero(I->getOperand(0), Mask) &&
|
|
MaskedValueIsZero(I->getOperand(1), Mask)) {
|
|
return CanEvaluateTruncated(I->getOperand(0), Ty) &&
|
|
CanEvaluateTruncated(I->getOperand(1), Ty);
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
case Instruction::Shl:
|
|
// If we are truncating the result of this SHL, and if it's a shift of a
|
|
// constant amount, we can always perform a SHL in a smaller type.
|
|
if (ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(1))) {
|
|
uint32_t BitWidth = Ty->getScalarSizeInBits();
|
|
if (CI->getLimitedValue(BitWidth) < BitWidth)
|
|
return CanEvaluateTruncated(I->getOperand(0), Ty);
|
|
}
|
|
break;
|
|
case Instruction::LShr:
|
|
// If this is a truncate of a logical shr, we can truncate it to a smaller
|
|
// lshr iff we know that the bits we would otherwise be shifting in are
|
|
// already zeros.
|
|
if (ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(1))) {
|
|
uint32_t OrigBitWidth = OrigTy->getScalarSizeInBits();
|
|
uint32_t BitWidth = Ty->getScalarSizeInBits();
|
|
if (MaskedValueIsZero(I->getOperand(0),
|
|
APInt::getHighBitsSet(OrigBitWidth, OrigBitWidth-BitWidth)) &&
|
|
CI->getLimitedValue(BitWidth) < BitWidth) {
|
|
return CanEvaluateTruncated(I->getOperand(0), Ty);
|
|
}
|
|
}
|
|
break;
|
|
case Instruction::Trunc:
|
|
// trunc(trunc(x)) -> trunc(x)
|
|
return true;
|
|
case Instruction::Select: {
|
|
SelectInst *SI = cast<SelectInst>(I);
|
|
return CanEvaluateTruncated(SI->getTrueValue(), Ty) &&
|
|
CanEvaluateTruncated(SI->getFalseValue(), Ty);
|
|
}
|
|
case Instruction::PHI: {
|
|
// We can change a phi if we can change all operands. Note that we never
|
|
// get into trouble with cyclic PHIs here because we only consider
|
|
// instructions with a single use.
|
|
PHINode *PN = cast<PHINode>(I);
|
|
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
|
|
if (!CanEvaluateTruncated(PN->getIncomingValue(i), Ty))
|
|
return false;
|
|
return true;
|
|
}
|
|
default:
|
|
// TODO: Can handle more cases here.
|
|
break;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
Instruction *InstCombiner::visitTrunc(TruncInst &CI) {
|
|
if (Instruction *Result = commonCastTransforms(CI))
|
|
return Result;
|
|
|
|
// See if we can simplify any instructions used by the input whose sole
|
|
// purpose is to compute bits we don't care about.
|
|
if (SimplifyDemandedInstructionBits(CI))
|
|
return &CI;
|
|
|
|
Value *Src = CI.getOperand(0);
|
|
const Type *DestTy = CI.getType(), *SrcTy = Src->getType();
|
|
|
|
// Attempt to truncate the entire input expression tree to the destination
|
|
// type. Only do this if the dest type is a simple type, don't convert the
|
|
// expression tree to something weird like i93 unless the source is also
|
|
// strange.
|
|
if ((DestTy->isVectorTy() || ShouldChangeType(SrcTy, DestTy)) &&
|
|
CanEvaluateTruncated(Src, DestTy)) {
|
|
|
|
// If this cast is a truncate, evaluting in a different type always
|
|
// eliminates the cast, so it is always a win.
|
|
DEBUG(dbgs() << "ICE: EvaluateInDifferentType converting expression type"
|
|
" to avoid cast: " << CI << '\n');
|
|
Value *Res = EvaluateInDifferentType(Src, DestTy, false);
|
|
assert(Res->getType() == DestTy);
|
|
return ReplaceInstUsesWith(CI, Res);
|
|
}
|
|
|
|
// Canonicalize trunc x to i1 -> (icmp ne (and x, 1), 0), likewise for vector.
|
|
if (DestTy->getScalarSizeInBits() == 1) {
|
|
Constant *One = ConstantInt::get(Src->getType(), 1);
|
|
Src = Builder->CreateAnd(Src, One, "tmp");
|
|
Value *Zero = Constant::getNullValue(Src->getType());
|
|
return new ICmpInst(ICmpInst::ICMP_NE, Src, Zero);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/// transformZExtICmp - Transform (zext icmp) to bitwise / integer operations
|
|
/// in order to eliminate the icmp.
|
|
Instruction *InstCombiner::transformZExtICmp(ICmpInst *ICI, Instruction &CI,
|
|
bool DoXform) {
|
|
// If we are just checking for a icmp eq of a single bit and zext'ing it
|
|
// to an integer, then shift the bit to the appropriate place and then
|
|
// cast to integer to avoid the comparison.
|
|
if (ConstantInt *Op1C = dyn_cast<ConstantInt>(ICI->getOperand(1))) {
|
|
const APInt &Op1CV = Op1C->getValue();
|
|
|
|
// zext (x <s 0) to i32 --> x>>u31 true if signbit set.
|
|
// zext (x >s -1) to i32 --> (x>>u31)^1 true if signbit clear.
|
|
if ((ICI->getPredicate() == ICmpInst::ICMP_SLT && Op1CV == 0) ||
|
|
(ICI->getPredicate() == ICmpInst::ICMP_SGT &&Op1CV.isAllOnesValue())) {
|
|
if (!DoXform) return ICI;
|
|
|
|
Value *In = ICI->getOperand(0);
|
|
Value *Sh = ConstantInt::get(In->getType(),
|
|
In->getType()->getScalarSizeInBits()-1);
|
|
In = Builder->CreateLShr(In, Sh, In->getName()+".lobit");
|
|
if (In->getType() != CI.getType())
|
|
In = Builder->CreateIntCast(In, CI.getType(), false/*ZExt*/, "tmp");
|
|
|
|
if (ICI->getPredicate() == ICmpInst::ICMP_SGT) {
|
|
Constant *One = ConstantInt::get(In->getType(), 1);
|
|
In = Builder->CreateXor(In, One, In->getName()+".not");
|
|
}
|
|
|
|
return ReplaceInstUsesWith(CI, In);
|
|
}
|
|
|
|
|
|
|
|
// zext (X == 0) to i32 --> X^1 iff X has only the low bit set.
|
|
// zext (X == 0) to i32 --> (X>>1)^1 iff X has only the 2nd bit set.
|
|
// zext (X == 1) to i32 --> X iff X has only the low bit set.
|
|
// zext (X == 2) to i32 --> X>>1 iff X has only the 2nd bit set.
|
|
// zext (X != 0) to i32 --> X iff X has only the low bit set.
|
|
// zext (X != 0) to i32 --> X>>1 iff X has only the 2nd bit set.
|
|
// zext (X != 1) to i32 --> X^1 iff X has only the low bit set.
|
|
// zext (X != 2) to i32 --> (X>>1)^1 iff X has only the 2nd bit set.
|
|
if ((Op1CV == 0 || Op1CV.isPowerOf2()) &&
|
|
// This only works for EQ and NE
|
|
ICI->isEquality()) {
|
|
// If Op1C some other power of two, convert:
|
|
uint32_t BitWidth = Op1C->getType()->getBitWidth();
|
|
APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
|
|
APInt TypeMask(APInt::getAllOnesValue(BitWidth));
|
|
ComputeMaskedBits(ICI->getOperand(0), TypeMask, KnownZero, KnownOne);
|
|
|
|
APInt KnownZeroMask(~KnownZero);
|
|
if (KnownZeroMask.isPowerOf2()) { // Exactly 1 possible 1?
|
|
if (!DoXform) return ICI;
|
|
|
|
bool isNE = ICI->getPredicate() == ICmpInst::ICMP_NE;
|
|
if (Op1CV != 0 && (Op1CV != KnownZeroMask)) {
|
|
// (X&4) == 2 --> false
|
|
// (X&4) != 2 --> true
|
|
Constant *Res = ConstantInt::get(Type::getInt1Ty(CI.getContext()),
|
|
isNE);
|
|
Res = ConstantExpr::getZExt(Res, CI.getType());
|
|
return ReplaceInstUsesWith(CI, Res);
|
|
}
|
|
|
|
uint32_t ShiftAmt = KnownZeroMask.logBase2();
|
|
Value *In = ICI->getOperand(0);
|
|
if (ShiftAmt) {
|
|
// Perform a logical shr by shiftamt.
|
|
// Insert the shift to put the result in the low bit.
|
|
In = Builder->CreateLShr(In, ConstantInt::get(In->getType(),ShiftAmt),
|
|
In->getName()+".lobit");
|
|
}
|
|
|
|
if ((Op1CV != 0) == isNE) { // Toggle the low bit.
|
|
Constant *One = ConstantInt::get(In->getType(), 1);
|
|
In = Builder->CreateXor(In, One, "tmp");
|
|
}
|
|
|
|
if (CI.getType() == In->getType())
|
|
return ReplaceInstUsesWith(CI, In);
|
|
else
|
|
return CastInst::CreateIntegerCast(In, CI.getType(), false/*ZExt*/);
|
|
}
|
|
}
|
|
}
|
|
|
|
// icmp ne A, B is equal to xor A, B when A and B only really have one bit.
|
|
// It is also profitable to transform icmp eq into not(xor(A, B)) because that
|
|
// may lead to additional simplifications.
|
|
if (ICI->isEquality() && CI.getType() == ICI->getOperand(0)->getType()) {
|
|
if (const IntegerType *ITy = dyn_cast<IntegerType>(CI.getType())) {
|
|
uint32_t BitWidth = ITy->getBitWidth();
|
|
Value *LHS = ICI->getOperand(0);
|
|
Value *RHS = ICI->getOperand(1);
|
|
|
|
APInt KnownZeroLHS(BitWidth, 0), KnownOneLHS(BitWidth, 0);
|
|
APInt KnownZeroRHS(BitWidth, 0), KnownOneRHS(BitWidth, 0);
|
|
APInt TypeMask(APInt::getAllOnesValue(BitWidth));
|
|
ComputeMaskedBits(LHS, TypeMask, KnownZeroLHS, KnownOneLHS);
|
|
ComputeMaskedBits(RHS, TypeMask, KnownZeroRHS, KnownOneRHS);
|
|
|
|
if (KnownZeroLHS == KnownZeroRHS && KnownOneLHS == KnownOneRHS) {
|
|
APInt KnownBits = KnownZeroLHS | KnownOneLHS;
|
|
APInt UnknownBit = ~KnownBits;
|
|
if (UnknownBit.countPopulation() == 1) {
|
|
if (!DoXform) return ICI;
|
|
|
|
Value *Result = Builder->CreateXor(LHS, RHS);
|
|
|
|
// Mask off any bits that are set and won't be shifted away.
|
|
if (KnownOneLHS.uge(UnknownBit))
|
|
Result = Builder->CreateAnd(Result,
|
|
ConstantInt::get(ITy, UnknownBit));
|
|
|
|
// Shift the bit we're testing down to the lsb.
|
|
Result = Builder->CreateLShr(
|
|
Result, ConstantInt::get(ITy, UnknownBit.countTrailingZeros()));
|
|
|
|
if (ICI->getPredicate() == ICmpInst::ICMP_EQ)
|
|
Result = Builder->CreateXor(Result, ConstantInt::get(ITy, 1));
|
|
Result->takeName(ICI);
|
|
return ReplaceInstUsesWith(CI, Result);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/// CanEvaluateZExtd - Determine if the specified value can be computed in the
|
|
/// specified wider type and produce the same low bits. If not, return false.
|
|
///
|
|
/// If this function returns true, it can also return a non-zero number of bits
|
|
/// (in BitsToClear) which indicates that the value it computes is correct for
|
|
/// the zero extend, but that the additional BitsToClear bits need to be zero'd
|
|
/// out. For example, to promote something like:
|
|
///
|
|
/// %B = trunc i64 %A to i32
|
|
/// %C = lshr i32 %B, 8
|
|
/// %E = zext i32 %C to i64
|
|
///
|
|
/// CanEvaluateZExtd for the 'lshr' will return true, and BitsToClear will be
|
|
/// set to 8 to indicate that the promoted value needs to have bits 24-31
|
|
/// cleared in addition to bits 32-63. Since an 'and' will be generated to
|
|
/// clear the top bits anyway, doing this has no extra cost.
|
|
///
|
|
/// This function works on both vectors and scalars.
|
|
static bool CanEvaluateZExtd(Value *V, const Type *Ty, unsigned &BitsToClear) {
|
|
BitsToClear = 0;
|
|
if (isa<Constant>(V))
|
|
return true;
|
|
|
|
Instruction *I = dyn_cast<Instruction>(V);
|
|
if (!I) return false;
|
|
|
|
// If the input is a truncate from the destination type, we can trivially
|
|
// eliminate it, even if it has multiple uses.
|
|
// FIXME: This is currently disabled until codegen can handle this without
|
|
// pessimizing code, PR5997.
|
|
if (0 && isa<TruncInst>(I) && I->getOperand(0)->getType() == Ty)
|
|
return true;
|
|
|
|
// We can't extend or shrink something that has multiple uses: doing so would
|
|
// require duplicating the instruction in general, which isn't profitable.
|
|
if (!I->hasOneUse()) return false;
|
|
|
|
unsigned Opc = I->getOpcode(), Tmp;
|
|
switch (Opc) {
|
|
case Instruction::ZExt: // zext(zext(x)) -> zext(x).
|
|
case Instruction::SExt: // zext(sext(x)) -> sext(x).
|
|
case Instruction::Trunc: // zext(trunc(x)) -> trunc(x) or zext(x)
|
|
return true;
|
|
case Instruction::And:
|
|
case Instruction::Or:
|
|
case Instruction::Xor:
|
|
case Instruction::Add:
|
|
case Instruction::Sub:
|
|
case Instruction::Mul:
|
|
case Instruction::Shl:
|
|
if (!CanEvaluateZExtd(I->getOperand(0), Ty, BitsToClear) ||
|
|
!CanEvaluateZExtd(I->getOperand(1), Ty, Tmp))
|
|
return false;
|
|
// These can all be promoted if neither operand has 'bits to clear'.
|
|
if (BitsToClear == 0 && Tmp == 0)
|
|
return true;
|
|
|
|
// If the operation is an AND/OR/XOR and the bits to clear are zero in the
|
|
// other side, BitsToClear is ok.
|
|
if (Tmp == 0 &&
|
|
(Opc == Instruction::And || Opc == Instruction::Or ||
|
|
Opc == Instruction::Xor)) {
|
|
// We use MaskedValueIsZero here for generality, but the case we care
|
|
// about the most is constant RHS.
|
|
unsigned VSize = V->getType()->getScalarSizeInBits();
|
|
if (MaskedValueIsZero(I->getOperand(1),
|
|
APInt::getHighBitsSet(VSize, BitsToClear)))
|
|
return true;
|
|
}
|
|
|
|
// Otherwise, we don't know how to analyze this BitsToClear case yet.
|
|
return false;
|
|
|
|
case Instruction::LShr:
|
|
// We can promote lshr(x, cst) if we can promote x. This requires the
|
|
// ultimate 'and' to clear out the high zero bits we're clearing out though.
|
|
if (ConstantInt *Amt = dyn_cast<ConstantInt>(I->getOperand(1))) {
|
|
if (!CanEvaluateZExtd(I->getOperand(0), Ty, BitsToClear))
|
|
return false;
|
|
BitsToClear += Amt->getZExtValue();
|
|
if (BitsToClear > V->getType()->getScalarSizeInBits())
|
|
BitsToClear = V->getType()->getScalarSizeInBits();
|
|
return true;
|
|
}
|
|
// Cannot promote variable LSHR.
|
|
return false;
|
|
case Instruction::Select:
|
|
if (!CanEvaluateZExtd(I->getOperand(1), Ty, Tmp) ||
|
|
!CanEvaluateZExtd(I->getOperand(2), Ty, BitsToClear) ||
|
|
// TODO: If important, we could handle the case when the BitsToClear are
|
|
// known zero in the disagreeing side.
|
|
Tmp != BitsToClear)
|
|
return false;
|
|
return true;
|
|
|
|
case Instruction::PHI: {
|
|
// We can change a phi if we can change all operands. Note that we never
|
|
// get into trouble with cyclic PHIs here because we only consider
|
|
// instructions with a single use.
|
|
PHINode *PN = cast<PHINode>(I);
|
|
if (!CanEvaluateZExtd(PN->getIncomingValue(0), Ty, BitsToClear))
|
|
return false;
|
|
for (unsigned i = 1, e = PN->getNumIncomingValues(); i != e; ++i)
|
|
if (!CanEvaluateZExtd(PN->getIncomingValue(i), Ty, Tmp) ||
|
|
// TODO: If important, we could handle the case when the BitsToClear
|
|
// are known zero in the disagreeing input.
|
|
Tmp != BitsToClear)
|
|
return false;
|
|
return true;
|
|
}
|
|
default:
|
|
// TODO: Can handle more cases here.
|
|
return false;
|
|
}
|
|
}
|
|
|
|
Instruction *InstCombiner::visitZExt(ZExtInst &CI) {
|
|
// If this zero extend is only used by a truncate, let the truncate by
|
|
// eliminated before we try to optimize this zext.
|
|
if (CI.hasOneUse() && isa<TruncInst>(CI.use_back()))
|
|
return 0;
|
|
|
|
// If one of the common conversion will work, do it.
|
|
if (Instruction *Result = commonCastTransforms(CI))
|
|
return Result;
|
|
|
|
// See if we can simplify any instructions used by the input whose sole
|
|
// purpose is to compute bits we don't care about.
|
|
if (SimplifyDemandedInstructionBits(CI))
|
|
return &CI;
|
|
|
|
Value *Src = CI.getOperand(0);
|
|
const Type *SrcTy = Src->getType(), *DestTy = CI.getType();
|
|
|
|
// Attempt to extend the entire input expression tree to the destination
|
|
// type. Only do this if the dest type is a simple type, don't convert the
|
|
// expression tree to something weird like i93 unless the source is also
|
|
// strange.
|
|
unsigned BitsToClear;
|
|
if ((DestTy->isVectorTy() || ShouldChangeType(SrcTy, DestTy)) &&
|
|
CanEvaluateZExtd(Src, DestTy, BitsToClear)) {
|
|
assert(BitsToClear < SrcTy->getScalarSizeInBits() &&
|
|
"Unreasonable BitsToClear");
|
|
|
|
// Okay, we can transform this! Insert the new expression now.
|
|
DEBUG(dbgs() << "ICE: EvaluateInDifferentType converting expression type"
|
|
" to avoid zero extend: " << CI);
|
|
Value *Res = EvaluateInDifferentType(Src, DestTy, false);
|
|
assert(Res->getType() == DestTy);
|
|
|
|
uint32_t SrcBitsKept = SrcTy->getScalarSizeInBits()-BitsToClear;
|
|
uint32_t DestBitSize = DestTy->getScalarSizeInBits();
|
|
|
|
// If the high bits are already filled with zeros, just replace this
|
|
// cast with the result.
|
|
if (MaskedValueIsZero(Res, APInt::getHighBitsSet(DestBitSize,
|
|
DestBitSize-SrcBitsKept)))
|
|
return ReplaceInstUsesWith(CI, Res);
|
|
|
|
// We need to emit an AND to clear the high bits.
|
|
Constant *C = ConstantInt::get(Res->getType(),
|
|
APInt::getLowBitsSet(DestBitSize, SrcBitsKept));
|
|
return BinaryOperator::CreateAnd(Res, C);
|
|
}
|
|
|
|
// If this is a TRUNC followed by a ZEXT then we are dealing with integral
|
|
// types and if the sizes are just right we can convert this into a logical
|
|
// 'and' which will be much cheaper than the pair of casts.
|
|
if (TruncInst *CSrc = dyn_cast<TruncInst>(Src)) { // A->B->C cast
|
|
// TODO: Subsume this into EvaluateInDifferentType.
|
|
|
|
// Get the sizes of the types involved. We know that the intermediate type
|
|
// will be smaller than A or C, but don't know the relation between A and C.
|
|
Value *A = CSrc->getOperand(0);
|
|
unsigned SrcSize = A->getType()->getScalarSizeInBits();
|
|
unsigned MidSize = CSrc->getType()->getScalarSizeInBits();
|
|
unsigned DstSize = CI.getType()->getScalarSizeInBits();
|
|
// If we're actually extending zero bits, then if
|
|
// SrcSize < DstSize: zext(a & mask)
|
|
// SrcSize == DstSize: a & mask
|
|
// SrcSize > DstSize: trunc(a) & mask
|
|
if (SrcSize < DstSize) {
|
|
APInt AndValue(APInt::getLowBitsSet(SrcSize, MidSize));
|
|
Constant *AndConst = ConstantInt::get(A->getType(), AndValue);
|
|
Value *And = Builder->CreateAnd(A, AndConst, CSrc->getName()+".mask");
|
|
return new ZExtInst(And, CI.getType());
|
|
}
|
|
|
|
if (SrcSize == DstSize) {
|
|
APInt AndValue(APInt::getLowBitsSet(SrcSize, MidSize));
|
|
return BinaryOperator::CreateAnd(A, ConstantInt::get(A->getType(),
|
|
AndValue));
|
|
}
|
|
if (SrcSize > DstSize) {
|
|
Value *Trunc = Builder->CreateTrunc(A, CI.getType(), "tmp");
|
|
APInt AndValue(APInt::getLowBitsSet(DstSize, MidSize));
|
|
return BinaryOperator::CreateAnd(Trunc,
|
|
ConstantInt::get(Trunc->getType(),
|
|
AndValue));
|
|
}
|
|
}
|
|
|
|
if (ICmpInst *ICI = dyn_cast<ICmpInst>(Src))
|
|
return transformZExtICmp(ICI, CI);
|
|
|
|
BinaryOperator *SrcI = dyn_cast<BinaryOperator>(Src);
|
|
if (SrcI && SrcI->getOpcode() == Instruction::Or) {
|
|
// zext (or icmp, icmp) --> or (zext icmp), (zext icmp) if at least one
|
|
// of the (zext icmp) will be transformed.
|
|
ICmpInst *LHS = dyn_cast<ICmpInst>(SrcI->getOperand(0));
|
|
ICmpInst *RHS = dyn_cast<ICmpInst>(SrcI->getOperand(1));
|
|
if (LHS && RHS && LHS->hasOneUse() && RHS->hasOneUse() &&
|
|
(transformZExtICmp(LHS, CI, false) ||
|
|
transformZExtICmp(RHS, CI, false))) {
|
|
Value *LCast = Builder->CreateZExt(LHS, CI.getType(), LHS->getName());
|
|
Value *RCast = Builder->CreateZExt(RHS, CI.getType(), RHS->getName());
|
|
return BinaryOperator::Create(Instruction::Or, LCast, RCast);
|
|
}
|
|
}
|
|
|
|
// zext(trunc(t) & C) -> (t & zext(C)).
|
|
if (SrcI && SrcI->getOpcode() == Instruction::And && SrcI->hasOneUse())
|
|
if (ConstantInt *C = dyn_cast<ConstantInt>(SrcI->getOperand(1)))
|
|
if (TruncInst *TI = dyn_cast<TruncInst>(SrcI->getOperand(0))) {
|
|
Value *TI0 = TI->getOperand(0);
|
|
if (TI0->getType() == CI.getType())
|
|
return
|
|
BinaryOperator::CreateAnd(TI0,
|
|
ConstantExpr::getZExt(C, CI.getType()));
|
|
}
|
|
|
|
// zext((trunc(t) & C) ^ C) -> ((t & zext(C)) ^ zext(C)).
|
|
if (SrcI && SrcI->getOpcode() == Instruction::Xor && SrcI->hasOneUse())
|
|
if (ConstantInt *C = dyn_cast<ConstantInt>(SrcI->getOperand(1)))
|
|
if (BinaryOperator *And = dyn_cast<BinaryOperator>(SrcI->getOperand(0)))
|
|
if (And->getOpcode() == Instruction::And && And->hasOneUse() &&
|
|
And->getOperand(1) == C)
|
|
if (TruncInst *TI = dyn_cast<TruncInst>(And->getOperand(0))) {
|
|
Value *TI0 = TI->getOperand(0);
|
|
if (TI0->getType() == CI.getType()) {
|
|
Constant *ZC = ConstantExpr::getZExt(C, CI.getType());
|
|
Value *NewAnd = Builder->CreateAnd(TI0, ZC, "tmp");
|
|
return BinaryOperator::CreateXor(NewAnd, ZC);
|
|
}
|
|
}
|
|
|
|
// zext (xor i1 X, true) to i32 --> xor (zext i1 X to i32), 1
|
|
Value *X;
|
|
if (SrcI && SrcI->hasOneUse() && SrcI->getType()->isIntegerTy(1) &&
|
|
match(SrcI, m_Not(m_Value(X))) &&
|
|
(!X->hasOneUse() || !isa<CmpInst>(X))) {
|
|
Value *New = Builder->CreateZExt(X, CI.getType());
|
|
return BinaryOperator::CreateXor(New, ConstantInt::get(CI.getType(), 1));
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/// CanEvaluateSExtd - Return true if we can take the specified value
|
|
/// and return it as type Ty without inserting any new casts and without
|
|
/// changing the value of the common low bits. This is used by code that tries
|
|
/// to promote integer operations to a wider types will allow us to eliminate
|
|
/// the extension.
|
|
///
|
|
/// This function works on both vectors and scalars.
|
|
///
|
|
static bool CanEvaluateSExtd(Value *V, const Type *Ty) {
|
|
assert(V->getType()->getScalarSizeInBits() < Ty->getScalarSizeInBits() &&
|
|
"Can't sign extend type to a smaller type");
|
|
// If this is a constant, it can be trivially promoted.
|
|
if (isa<Constant>(V))
|
|
return true;
|
|
|
|
Instruction *I = dyn_cast<Instruction>(V);
|
|
if (!I) return false;
|
|
|
|
// If this is a truncate from the dest type, we can trivially eliminate it,
|
|
// even if it has multiple uses.
|
|
// FIXME: This is currently disabled until codegen can handle this without
|
|
// pessimizing code, PR5997.
|
|
if (0 && isa<TruncInst>(I) && I->getOperand(0)->getType() == Ty)
|
|
return true;
|
|
|
|
// We can't extend or shrink something that has multiple uses: doing so would
|
|
// require duplicating the instruction in general, which isn't profitable.
|
|
if (!I->hasOneUse()) return false;
|
|
|
|
switch (I->getOpcode()) {
|
|
case Instruction::SExt: // sext(sext(x)) -> sext(x)
|
|
case Instruction::ZExt: // sext(zext(x)) -> zext(x)
|
|
case Instruction::Trunc: // sext(trunc(x)) -> trunc(x) or sext(x)
|
|
return true;
|
|
case Instruction::And:
|
|
case Instruction::Or:
|
|
case Instruction::Xor:
|
|
case Instruction::Add:
|
|
case Instruction::Sub:
|
|
case Instruction::Mul:
|
|
// These operators can all arbitrarily be extended if their inputs can.
|
|
return CanEvaluateSExtd(I->getOperand(0), Ty) &&
|
|
CanEvaluateSExtd(I->getOperand(1), Ty);
|
|
|
|
//case Instruction::Shl: TODO
|
|
//case Instruction::LShr: TODO
|
|
|
|
case Instruction::Select:
|
|
return CanEvaluateSExtd(I->getOperand(1), Ty) &&
|
|
CanEvaluateSExtd(I->getOperand(2), Ty);
|
|
|
|
case Instruction::PHI: {
|
|
// We can change a phi if we can change all operands. Note that we never
|
|
// get into trouble with cyclic PHIs here because we only consider
|
|
// instructions with a single use.
|
|
PHINode *PN = cast<PHINode>(I);
|
|
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
|
|
if (!CanEvaluateSExtd(PN->getIncomingValue(i), Ty)) return false;
|
|
return true;
|
|
}
|
|
default:
|
|
// TODO: Can handle more cases here.
|
|
break;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
Instruction *InstCombiner::visitSExt(SExtInst &CI) {
|
|
// If this sign extend is only used by a truncate, let the truncate by
|
|
// eliminated before we try to optimize this zext.
|
|
if (CI.hasOneUse() && isa<TruncInst>(CI.use_back()))
|
|
return 0;
|
|
|
|
if (Instruction *I = commonCastTransforms(CI))
|
|
return I;
|
|
|
|
// See if we can simplify any instructions used by the input whose sole
|
|
// purpose is to compute bits we don't care about.
|
|
if (SimplifyDemandedInstructionBits(CI))
|
|
return &CI;
|
|
|
|
Value *Src = CI.getOperand(0);
|
|
const Type *SrcTy = Src->getType(), *DestTy = CI.getType();
|
|
|
|
// Attempt to extend the entire input expression tree to the destination
|
|
// type. Only do this if the dest type is a simple type, don't convert the
|
|
// expression tree to something weird like i93 unless the source is also
|
|
// strange.
|
|
if ((DestTy->isVectorTy() || ShouldChangeType(SrcTy, DestTy)) &&
|
|
CanEvaluateSExtd(Src, DestTy)) {
|
|
// Okay, we can transform this! Insert the new expression now.
|
|
DEBUG(dbgs() << "ICE: EvaluateInDifferentType converting expression type"
|
|
" to avoid sign extend: " << CI);
|
|
Value *Res = EvaluateInDifferentType(Src, DestTy, true);
|
|
assert(Res->getType() == DestTy);
|
|
|
|
uint32_t SrcBitSize = SrcTy->getScalarSizeInBits();
|
|
uint32_t DestBitSize = DestTy->getScalarSizeInBits();
|
|
|
|
// If the high bits are already filled with sign bit, just replace this
|
|
// cast with the result.
|
|
if (ComputeNumSignBits(Res) > DestBitSize - SrcBitSize)
|
|
return ReplaceInstUsesWith(CI, Res);
|
|
|
|
// We need to emit a shl + ashr to do the sign extend.
|
|
Value *ShAmt = ConstantInt::get(DestTy, DestBitSize-SrcBitSize);
|
|
return BinaryOperator::CreateAShr(Builder->CreateShl(Res, ShAmt, "sext"),
|
|
ShAmt);
|
|
}
|
|
|
|
// If this input is a trunc from our destination, then turn sext(trunc(x))
|
|
// into shifts.
|
|
if (TruncInst *TI = dyn_cast<TruncInst>(Src))
|
|
if (TI->hasOneUse() && TI->getOperand(0)->getType() == DestTy) {
|
|
uint32_t SrcBitSize = SrcTy->getScalarSizeInBits();
|
|
uint32_t DestBitSize = DestTy->getScalarSizeInBits();
|
|
|
|
// We need to emit a shl + ashr to do the sign extend.
|
|
Value *ShAmt = ConstantInt::get(DestTy, DestBitSize-SrcBitSize);
|
|
Value *Res = Builder->CreateShl(TI->getOperand(0), ShAmt, "sext");
|
|
return BinaryOperator::CreateAShr(Res, ShAmt);
|
|
}
|
|
|
|
|
|
// (x <s 0) ? -1 : 0 -> ashr x, 31 -> all ones if signed
|
|
// (x >s -1) ? -1 : 0 -> ashr x, 31 -> all ones if not signed
|
|
{
|
|
ICmpInst::Predicate Pred; Value *CmpLHS; ConstantInt *CmpRHS;
|
|
if (match(Src, m_ICmp(Pred, m_Value(CmpLHS), m_ConstantInt(CmpRHS)))) {
|
|
// sext (x <s 0) to i32 --> x>>s31 true if signbit set.
|
|
// sext (x >s -1) to i32 --> (x>>s31)^-1 true if signbit clear.
|
|
if ((Pred == ICmpInst::ICMP_SLT && CmpRHS->isZero()) ||
|
|
(Pred == ICmpInst::ICMP_SGT && CmpRHS->isAllOnesValue())) {
|
|
Value *Sh = ConstantInt::get(CmpLHS->getType(),
|
|
CmpLHS->getType()->getScalarSizeInBits()-1);
|
|
Value *In = Builder->CreateAShr(CmpLHS, Sh, CmpLHS->getName()+".lobit");
|
|
if (In->getType() != CI.getType())
|
|
In = Builder->CreateIntCast(In, CI.getType(), true/*SExt*/, "tmp");
|
|
|
|
if (Pred == ICmpInst::ICMP_SGT)
|
|
In = Builder->CreateNot(In, In->getName()+".not");
|
|
return ReplaceInstUsesWith(CI, In);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
// If the input is a shl/ashr pair of a same constant, then this is a sign
|
|
// extension from a smaller value. If we could trust arbitrary bitwidth
|
|
// integers, we could turn this into a truncate to the smaller bit and then
|
|
// use a sext for the whole extension. Since we don't, look deeper and check
|
|
// for a truncate. If the source and dest are the same type, eliminate the
|
|
// trunc and extend and just do shifts. For example, turn:
|
|
// %a = trunc i32 %i to i8
|
|
// %b = shl i8 %a, 6
|
|
// %c = ashr i8 %b, 6
|
|
// %d = sext i8 %c to i32
|
|
// into:
|
|
// %a = shl i32 %i, 30
|
|
// %d = ashr i32 %a, 30
|
|
Value *A = 0;
|
|
// TODO: Eventually this could be subsumed by EvaluateInDifferentType.
|
|
ConstantInt *BA = 0, *CA = 0;
|
|
if (match(Src, m_AShr(m_Shl(m_Trunc(m_Value(A)), m_ConstantInt(BA)),
|
|
m_ConstantInt(CA))) &&
|
|
BA == CA && A->getType() == CI.getType()) {
|
|
unsigned MidSize = Src->getType()->getScalarSizeInBits();
|
|
unsigned SrcDstSize = CI.getType()->getScalarSizeInBits();
|
|
unsigned ShAmt = CA->getZExtValue()+SrcDstSize-MidSize;
|
|
Constant *ShAmtV = ConstantInt::get(CI.getType(), ShAmt);
|
|
A = Builder->CreateShl(A, ShAmtV, CI.getName());
|
|
return BinaryOperator::CreateAShr(A, ShAmtV);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
/// FitsInFPType - Return a Constant* for the specified FP constant if it fits
|
|
/// in the specified FP type without changing its value.
|
|
static Constant *FitsInFPType(ConstantFP *CFP, const fltSemantics &Sem) {
|
|
bool losesInfo;
|
|
APFloat F = CFP->getValueAPF();
|
|
(void)F.convert(Sem, APFloat::rmNearestTiesToEven, &losesInfo);
|
|
if (!losesInfo)
|
|
return ConstantFP::get(CFP->getContext(), F);
|
|
return 0;
|
|
}
|
|
|
|
/// LookThroughFPExtensions - If this is an fp extension instruction, look
|
|
/// through it until we get the source value.
|
|
static Value *LookThroughFPExtensions(Value *V) {
|
|
if (Instruction *I = dyn_cast<Instruction>(V))
|
|
if (I->getOpcode() == Instruction::FPExt)
|
|
return LookThroughFPExtensions(I->getOperand(0));
|
|
|
|
// If this value is a constant, return the constant in the smallest FP type
|
|
// that can accurately represent it. This allows us to turn
|
|
// (float)((double)X+2.0) into x+2.0f.
|
|
if (ConstantFP *CFP = dyn_cast<ConstantFP>(V)) {
|
|
if (CFP->getType() == Type::getPPC_FP128Ty(V->getContext()))
|
|
return V; // No constant folding of this.
|
|
// See if the value can be truncated to float and then reextended.
|
|
if (Value *V = FitsInFPType(CFP, APFloat::IEEEsingle))
|
|
return V;
|
|
if (CFP->getType()->isDoubleTy())
|
|
return V; // Won't shrink.
|
|
if (Value *V = FitsInFPType(CFP, APFloat::IEEEdouble))
|
|
return V;
|
|
// Don't try to shrink to various long double types.
|
|
}
|
|
|
|
return V;
|
|
}
|
|
|
|
Instruction *InstCombiner::visitFPTrunc(FPTruncInst &CI) {
|
|
if (Instruction *I = commonCastTransforms(CI))
|
|
return I;
|
|
|
|
// If we have fptrunc(fadd (fpextend x), (fpextend y)), where x and y are
|
|
// smaller than the destination type, we can eliminate the truncate by doing
|
|
// the add as the smaller type. This applies to fadd/fsub/fmul/fdiv as well
|
|
// as many builtins (sqrt, etc).
|
|
BinaryOperator *OpI = dyn_cast<BinaryOperator>(CI.getOperand(0));
|
|
if (OpI && OpI->hasOneUse()) {
|
|
switch (OpI->getOpcode()) {
|
|
default: break;
|
|
case Instruction::FAdd:
|
|
case Instruction::FSub:
|
|
case Instruction::FMul:
|
|
case Instruction::FDiv:
|
|
case Instruction::FRem:
|
|
const Type *SrcTy = OpI->getType();
|
|
Value *LHSTrunc = LookThroughFPExtensions(OpI->getOperand(0));
|
|
Value *RHSTrunc = LookThroughFPExtensions(OpI->getOperand(1));
|
|
if (LHSTrunc->getType() != SrcTy &&
|
|
RHSTrunc->getType() != SrcTy) {
|
|
unsigned DstSize = CI.getType()->getScalarSizeInBits();
|
|
// If the source types were both smaller than the destination type of
|
|
// the cast, do this xform.
|
|
if (LHSTrunc->getType()->getScalarSizeInBits() <= DstSize &&
|
|
RHSTrunc->getType()->getScalarSizeInBits() <= DstSize) {
|
|
LHSTrunc = Builder->CreateFPExt(LHSTrunc, CI.getType());
|
|
RHSTrunc = Builder->CreateFPExt(RHSTrunc, CI.getType());
|
|
return BinaryOperator::Create(OpI->getOpcode(), LHSTrunc, RHSTrunc);
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Fold (fptrunc (sqrt (fpext x))) -> (sqrtf x)
|
|
// NOTE: This should be disabled by -fno-builtin-sqrt if we ever support it.
|
|
CallInst *Call = dyn_cast<CallInst>(CI.getOperand(0));
|
|
if (Call && Call->getCalledFunction() &&
|
|
Call->getCalledFunction()->getName() == "sqrt" &&
|
|
Call->getNumArgOperands() == 1) {
|
|
CastInst *Arg = dyn_cast<CastInst>(Call->getArgOperand(0));
|
|
if (Arg && Arg->getOpcode() == Instruction::FPExt &&
|
|
CI.getType()->isFloatTy() &&
|
|
Call->getType()->isDoubleTy() &&
|
|
Arg->getType()->isDoubleTy() &&
|
|
Arg->getOperand(0)->getType()->isFloatTy()) {
|
|
Function *Callee = Call->getCalledFunction();
|
|
Module *M = CI.getParent()->getParent()->getParent();
|
|
Constant* SqrtfFunc = M->getOrInsertFunction("sqrtf",
|
|
Callee->getAttributes(),
|
|
Builder->getFloatTy(),
|
|
Builder->getFloatTy(),
|
|
NULL);
|
|
CallInst *ret = CallInst::Create(SqrtfFunc, Arg->getOperand(0),
|
|
"sqrtfcall");
|
|
ret->setAttributes(Callee->getAttributes());
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
Instruction *InstCombiner::visitFPExt(CastInst &CI) {
|
|
return commonCastTransforms(CI);
|
|
}
|
|
|
|
Instruction *InstCombiner::visitFPToUI(FPToUIInst &FI) {
|
|
Instruction *OpI = dyn_cast<Instruction>(FI.getOperand(0));
|
|
if (OpI == 0)
|
|
return commonCastTransforms(FI);
|
|
|
|
// fptoui(uitofp(X)) --> X
|
|
// fptoui(sitofp(X)) --> X
|
|
// This is safe if the intermediate type has enough bits in its mantissa to
|
|
// accurately represent all values of X. For example, do not do this with
|
|
// i64->float->i64. This is also safe for sitofp case, because any negative
|
|
// 'X' value would cause an undefined result for the fptoui.
|
|
if ((isa<UIToFPInst>(OpI) || isa<SIToFPInst>(OpI)) &&
|
|
OpI->getOperand(0)->getType() == FI.getType() &&
|
|
(int)FI.getType()->getScalarSizeInBits() < /*extra bit for sign */
|
|
OpI->getType()->getFPMantissaWidth())
|
|
return ReplaceInstUsesWith(FI, OpI->getOperand(0));
|
|
|
|
return commonCastTransforms(FI);
|
|
}
|
|
|
|
Instruction *InstCombiner::visitFPToSI(FPToSIInst &FI) {
|
|
Instruction *OpI = dyn_cast<Instruction>(FI.getOperand(0));
|
|
if (OpI == 0)
|
|
return commonCastTransforms(FI);
|
|
|
|
// fptosi(sitofp(X)) --> X
|
|
// fptosi(uitofp(X)) --> X
|
|
// This is safe if the intermediate type has enough bits in its mantissa to
|
|
// accurately represent all values of X. For example, do not do this with
|
|
// i64->float->i64. This is also safe for sitofp case, because any negative
|
|
// 'X' value would cause an undefined result for the fptoui.
|
|
if ((isa<UIToFPInst>(OpI) || isa<SIToFPInst>(OpI)) &&
|
|
OpI->getOperand(0)->getType() == FI.getType() &&
|
|
(int)FI.getType()->getScalarSizeInBits() <=
|
|
OpI->getType()->getFPMantissaWidth())
|
|
return ReplaceInstUsesWith(FI, OpI->getOperand(0));
|
|
|
|
return commonCastTransforms(FI);
|
|
}
|
|
|
|
Instruction *InstCombiner::visitUIToFP(CastInst &CI) {
|
|
return commonCastTransforms(CI);
|
|
}
|
|
|
|
Instruction *InstCombiner::visitSIToFP(CastInst &CI) {
|
|
return commonCastTransforms(CI);
|
|
}
|
|
|
|
Instruction *InstCombiner::visitIntToPtr(IntToPtrInst &CI) {
|
|
// If the source integer type is not the intptr_t type for this target, do a
|
|
// trunc or zext to the intptr_t type, then inttoptr of it. This allows the
|
|
// cast to be exposed to other transforms.
|
|
if (TD) {
|
|
if (CI.getOperand(0)->getType()->getScalarSizeInBits() >
|
|
TD->getPointerSizeInBits()) {
|
|
Value *P = Builder->CreateTrunc(CI.getOperand(0),
|
|
TD->getIntPtrType(CI.getContext()), "tmp");
|
|
return new IntToPtrInst(P, CI.getType());
|
|
}
|
|
if (CI.getOperand(0)->getType()->getScalarSizeInBits() <
|
|
TD->getPointerSizeInBits()) {
|
|
Value *P = Builder->CreateZExt(CI.getOperand(0),
|
|
TD->getIntPtrType(CI.getContext()), "tmp");
|
|
return new IntToPtrInst(P, CI.getType());
|
|
}
|
|
}
|
|
|
|
if (Instruction *I = commonCastTransforms(CI))
|
|
return I;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/// @brief Implement the transforms for cast of pointer (bitcast/ptrtoint)
|
|
Instruction *InstCombiner::commonPointerCastTransforms(CastInst &CI) {
|
|
Value *Src = CI.getOperand(0);
|
|
|
|
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Src)) {
|
|
// If casting the result of a getelementptr instruction with no offset, turn
|
|
// this into a cast of the original pointer!
|
|
if (GEP->hasAllZeroIndices()) {
|
|
// Changing the cast operand is usually not a good idea but it is safe
|
|
// here because the pointer operand is being replaced with another
|
|
// pointer operand so the opcode doesn't need to change.
|
|
Worklist.Add(GEP);
|
|
CI.setOperand(0, GEP->getOperand(0));
|
|
return &CI;
|
|
}
|
|
|
|
// If the GEP has a single use, and the base pointer is a bitcast, and the
|
|
// GEP computes a constant offset, see if we can convert these three
|
|
// instructions into fewer. This typically happens with unions and other
|
|
// non-type-safe code.
|
|
if (TD && GEP->hasOneUse() && isa<BitCastInst>(GEP->getOperand(0)) &&
|
|
GEP->hasAllConstantIndices()) {
|
|
// We are guaranteed to get a constant from EmitGEPOffset.
|
|
ConstantInt *OffsetV = cast<ConstantInt>(EmitGEPOffset(GEP));
|
|
int64_t Offset = OffsetV->getSExtValue();
|
|
|
|
// Get the base pointer input of the bitcast, and the type it points to.
|
|
Value *OrigBase = cast<BitCastInst>(GEP->getOperand(0))->getOperand(0);
|
|
const Type *GEPIdxTy =
|
|
cast<PointerType>(OrigBase->getType())->getElementType();
|
|
SmallVector<Value*, 8> NewIndices;
|
|
if (FindElementAtOffset(GEPIdxTy, Offset, NewIndices)) {
|
|
// If we were able to index down into an element, create the GEP
|
|
// and bitcast the result. This eliminates one bitcast, potentially
|
|
// two.
|
|
Value *NGEP = cast<GEPOperator>(GEP)->isInBounds() ?
|
|
Builder->CreateInBoundsGEP(OrigBase,
|
|
NewIndices.begin(), NewIndices.end()) :
|
|
Builder->CreateGEP(OrigBase, NewIndices.begin(), NewIndices.end());
|
|
NGEP->takeName(GEP);
|
|
|
|
if (isa<BitCastInst>(CI))
|
|
return new BitCastInst(NGEP, CI.getType());
|
|
assert(isa<PtrToIntInst>(CI));
|
|
return new PtrToIntInst(NGEP, CI.getType());
|
|
}
|
|
}
|
|
}
|
|
|
|
return commonCastTransforms(CI);
|
|
}
|
|
|
|
Instruction *InstCombiner::visitPtrToInt(PtrToIntInst &CI) {
|
|
// If the destination integer type is not the intptr_t type for this target,
|
|
// do a ptrtoint to intptr_t then do a trunc or zext. This allows the cast
|
|
// to be exposed to other transforms.
|
|
if (TD) {
|
|
if (CI.getType()->getScalarSizeInBits() < TD->getPointerSizeInBits()) {
|
|
Value *P = Builder->CreatePtrToInt(CI.getOperand(0),
|
|
TD->getIntPtrType(CI.getContext()),
|
|
"tmp");
|
|
return new TruncInst(P, CI.getType());
|
|
}
|
|
if (CI.getType()->getScalarSizeInBits() > TD->getPointerSizeInBits()) {
|
|
Value *P = Builder->CreatePtrToInt(CI.getOperand(0),
|
|
TD->getIntPtrType(CI.getContext()),
|
|
"tmp");
|
|
return new ZExtInst(P, CI.getType());
|
|
}
|
|
}
|
|
|
|
return commonPointerCastTransforms(CI);
|
|
}
|
|
|
|
/// OptimizeVectorResize - This input value (which is known to have vector type)
|
|
/// is being zero extended or truncated to the specified vector type. Try to
|
|
/// replace it with a shuffle (and vector/vector bitcast) if possible.
|
|
///
|
|
/// The source and destination vector types may have different element types.
|
|
static Instruction *OptimizeVectorResize(Value *InVal, const VectorType *DestTy,
|
|
InstCombiner &IC) {
|
|
// We can only do this optimization if the output is a multiple of the input
|
|
// element size, or the input is a multiple of the output element size.
|
|
// Convert the input type to have the same element type as the output.
|
|
const VectorType *SrcTy = cast<VectorType>(InVal->getType());
|
|
|
|
if (SrcTy->getElementType() != DestTy->getElementType()) {
|
|
// The input types don't need to be identical, but for now they must be the
|
|
// same size. There is no specific reason we couldn't handle things like
|
|
// <4 x i16> -> <4 x i32> by bitcasting to <2 x i32> but haven't gotten
|
|
// there yet.
|
|
if (SrcTy->getElementType()->getPrimitiveSizeInBits() !=
|
|
DestTy->getElementType()->getPrimitiveSizeInBits())
|
|
return 0;
|
|
|
|
SrcTy = VectorType::get(DestTy->getElementType(), SrcTy->getNumElements());
|
|
InVal = IC.Builder->CreateBitCast(InVal, SrcTy);
|
|
}
|
|
|
|
// Now that the element types match, get the shuffle mask and RHS of the
|
|
// shuffle to use, which depends on whether we're increasing or decreasing the
|
|
// size of the input.
|
|
SmallVector<Constant*, 16> ShuffleMask;
|
|
Value *V2;
|
|
const IntegerType *Int32Ty = Type::getInt32Ty(SrcTy->getContext());
|
|
|
|
if (SrcTy->getNumElements() > DestTy->getNumElements()) {
|
|
// If we're shrinking the number of elements, just shuffle in the low
|
|
// elements from the input and use undef as the second shuffle input.
|
|
V2 = UndefValue::get(SrcTy);
|
|
for (unsigned i = 0, e = DestTy->getNumElements(); i != e; ++i)
|
|
ShuffleMask.push_back(ConstantInt::get(Int32Ty, i));
|
|
|
|
} else {
|
|
// If we're increasing the number of elements, shuffle in all of the
|
|
// elements from InVal and fill the rest of the result elements with zeros
|
|
// from a constant zero.
|
|
V2 = Constant::getNullValue(SrcTy);
|
|
unsigned SrcElts = SrcTy->getNumElements();
|
|
for (unsigned i = 0, e = SrcElts; i != e; ++i)
|
|
ShuffleMask.push_back(ConstantInt::get(Int32Ty, i));
|
|
|
|
// The excess elements reference the first element of the zero input.
|
|
ShuffleMask.append(DestTy->getNumElements()-SrcElts,
|
|
ConstantInt::get(Int32Ty, SrcElts));
|
|
}
|
|
|
|
Constant *Mask = ConstantVector::get(ShuffleMask.data(), ShuffleMask.size());
|
|
return new ShuffleVectorInst(InVal, V2, Mask);
|
|
}
|
|
|
|
|
|
Instruction *InstCombiner::visitBitCast(BitCastInst &CI) {
|
|
// If the operands are integer typed then apply the integer transforms,
|
|
// otherwise just apply the common ones.
|
|
Value *Src = CI.getOperand(0);
|
|
const Type *SrcTy = Src->getType();
|
|
const Type *DestTy = CI.getType();
|
|
|
|
// Get rid of casts from one type to the same type. These are useless and can
|
|
// be replaced by the operand.
|
|
if (DestTy == Src->getType())
|
|
return ReplaceInstUsesWith(CI, Src);
|
|
|
|
if (const PointerType *DstPTy = dyn_cast<PointerType>(DestTy)) {
|
|
const PointerType *SrcPTy = cast<PointerType>(SrcTy);
|
|
const Type *DstElTy = DstPTy->getElementType();
|
|
const Type *SrcElTy = SrcPTy->getElementType();
|
|
|
|
// If the address spaces don't match, don't eliminate the bitcast, which is
|
|
// required for changing types.
|
|
if (SrcPTy->getAddressSpace() != DstPTy->getAddressSpace())
|
|
return 0;
|
|
|
|
// If we are casting a alloca to a pointer to a type of the same
|
|
// size, rewrite the allocation instruction to allocate the "right" type.
|
|
// There is no need to modify malloc calls because it is their bitcast that
|
|
// needs to be cleaned up.
|
|
if (AllocaInst *AI = dyn_cast<AllocaInst>(Src))
|
|
if (Instruction *V = PromoteCastOfAllocation(CI, *AI))
|
|
return V;
|
|
|
|
// If the source and destination are pointers, and this cast is equivalent
|
|
// to a getelementptr X, 0, 0, 0... turn it into the appropriate gep.
|
|
// This can enhance SROA and other transforms that want type-safe pointers.
|
|
Constant *ZeroUInt =
|
|
Constant::getNullValue(Type::getInt32Ty(CI.getContext()));
|
|
unsigned NumZeros = 0;
|
|
while (SrcElTy != DstElTy &&
|
|
isa<CompositeType>(SrcElTy) && !SrcElTy->isPointerTy() &&
|
|
SrcElTy->getNumContainedTypes() /* not "{}" */) {
|
|
SrcElTy = cast<CompositeType>(SrcElTy)->getTypeAtIndex(ZeroUInt);
|
|
++NumZeros;
|
|
}
|
|
|
|
// If we found a path from the src to dest, create the getelementptr now.
|
|
if (SrcElTy == DstElTy) {
|
|
SmallVector<Value*, 8> Idxs(NumZeros+1, ZeroUInt);
|
|
return GetElementPtrInst::CreateInBounds(Src, Idxs.begin(), Idxs.end(),"",
|
|
((Instruction*)NULL));
|
|
}
|
|
}
|
|
|
|
if (const VectorType *DestVTy = dyn_cast<VectorType>(DestTy)) {
|
|
if (DestVTy->getNumElements() == 1 && !SrcTy->isVectorTy()) {
|
|
Value *Elem = Builder->CreateBitCast(Src, DestVTy->getElementType());
|
|
return InsertElementInst::Create(UndefValue::get(DestTy), Elem,
|
|
Constant::getNullValue(Type::getInt32Ty(CI.getContext())));
|
|
// FIXME: Canonicalize bitcast(insertelement) -> insertelement(bitcast)
|
|
}
|
|
|
|
// If this is a cast from an integer to vector, check to see if the input
|
|
// is a trunc or zext of a bitcast from vector. If so, we can replace all
|
|
// the casts with a shuffle and (potentially) a bitcast.
|
|
if (isa<IntegerType>(SrcTy) && (isa<TruncInst>(Src) || isa<ZExtInst>(Src))){
|
|
CastInst *SrcCast = cast<CastInst>(Src);
|
|
if (BitCastInst *BCIn = dyn_cast<BitCastInst>(SrcCast->getOperand(0)))
|
|
if (isa<VectorType>(BCIn->getOperand(0)->getType()))
|
|
if (Instruction *I = OptimizeVectorResize(BCIn->getOperand(0),
|
|
cast<VectorType>(DestTy), *this))
|
|
return I;
|
|
}
|
|
}
|
|
|
|
if (const VectorType *SrcVTy = dyn_cast<VectorType>(SrcTy)) {
|
|
if (SrcVTy->getNumElements() == 1 && !DestTy->isVectorTy()) {
|
|
Value *Elem =
|
|
Builder->CreateExtractElement(Src,
|
|
Constant::getNullValue(Type::getInt32Ty(CI.getContext())));
|
|
return CastInst::Create(Instruction::BitCast, Elem, DestTy);
|
|
}
|
|
}
|
|
|
|
if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(Src)) {
|
|
// Okay, we have (bitcast (shuffle ..)). Check to see if this is
|
|
// a bitcast to a vector with the same # elts.
|
|
if (SVI->hasOneUse() && DestTy->isVectorTy() &&
|
|
cast<VectorType>(DestTy)->getNumElements() ==
|
|
SVI->getType()->getNumElements() &&
|
|
SVI->getType()->getNumElements() ==
|
|
cast<VectorType>(SVI->getOperand(0)->getType())->getNumElements()) {
|
|
BitCastInst *Tmp;
|
|
// If either of the operands is a cast from CI.getType(), then
|
|
// evaluating the shuffle in the casted destination's type will allow
|
|
// us to eliminate at least one cast.
|
|
if (((Tmp = dyn_cast<BitCastInst>(SVI->getOperand(0))) &&
|
|
Tmp->getOperand(0)->getType() == DestTy) ||
|
|
((Tmp = dyn_cast<BitCastInst>(SVI->getOperand(1))) &&
|
|
Tmp->getOperand(0)->getType() == DestTy)) {
|
|
Value *LHS = Builder->CreateBitCast(SVI->getOperand(0), DestTy);
|
|
Value *RHS = Builder->CreateBitCast(SVI->getOperand(1), DestTy);
|
|
// Return a new shuffle vector. Use the same element ID's, as we
|
|
// know the vector types match #elts.
|
|
return new ShuffleVectorInst(LHS, RHS, SVI->getOperand(2));
|
|
}
|
|
}
|
|
}
|
|
|
|
if (SrcTy->isPointerTy())
|
|
return commonPointerCastTransforms(CI);
|
|
return commonCastTransforms(CI);
|
|
}
|