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Lift the integer splat computation into a helper function. 

No functionality changed. Refactoring leading up to the fix for PR14478
which requires some significant changes to the memset and memcpy
rewriting.

llvm-svn: 170299
This commit is contained in:
Chandler Carruth 2012-12-17 04:07:30 +00:00
parent 588ceec0f7
commit 514f34f9c4
1 changed files with 28 additions and 11 deletions
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39
llvm/lib/Transforms/Scalar/SROA.cpp
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@ -2639,6 +2639,33 @@ private:
return NewSI->getPointerOperand() == &NewAI && !SI.isVolatile();
}
/// \brief Compute an integer value from splatting an i8 across the given
/// number of bytes.
///
/// Note that this routine assumes an i8 is a byte. If that isn't true, don't
/// call this routine.
/// FIXME: Heed the abvice above.
///
/// \param V The i8 value to splat.
/// \param Size The number of bytes in the output (assuming i8 is one byte)
Value *getIntegerSplat(IRBuilder<> &IRB, Value *V, unsigned Size) {
assert(Size > 0 && "Expected a positive number of bytes.");
IntegerType *VTy = cast<IntegerType>(V->getType());
assert(VTy->getBitWidth() == 8 && "Expected an i8 value for the byte");
if (Size == 1)
return V;
Type *SplatIntTy = Type::getIntNTy(VTy->getContext(), Size*8);
V = IRB.CreateMul(IRB.CreateZExt(V, SplatIntTy, getName(".zext")),
ConstantExpr::getUDiv(
Constant::getAllOnesValue(SplatIntTy),
ConstantExpr::getZExt(
Constant::getAllOnesValue(V->getType()),
SplatIntTy)),
getName(".isplat"));
return V;
}
bool visitMemSetInst(MemSetInst &II) {
DEBUG(dbgs() << " original: " << II << "\n");
IRBuilder<> IRB(&II);
@ -2686,17 +2713,7 @@ private:
// splatting the byte to a sufficiently wide integer, bitcasting to the
// desired scalar type, and splatting it across any desired vector type.
uint64_t Size = EndOffset - BeginOffset;
Value *V = II.getValue();
IntegerType *VTy = cast<IntegerType>(V->getType());
Type *SplatIntTy = Type::getIntNTy(VTy->getContext(), Size*8);
if (Size*8 > VTy->getBitWidth())
V = IRB.CreateMul(IRB.CreateZExt(V, SplatIntTy, getName(".zext")),
ConstantExpr::getUDiv(
Constant::getAllOnesValue(SplatIntTy),
ConstantExpr::getZExt(
Constant::getAllOnesValue(V->getType()),
SplatIntTy)),
getName(".isplat"));
Value *V = getIntegerSplat(IRB, II.getValue(), Size);
// If this is an element-wide memset of a vectorizable alloca, insert it.
if (VecTy && (BeginOffset > NewAllocaBeginOffset ||