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Update the memcpy rewriting to fully support widened int rewriting. This 

includes extracting ints for copying elsewhere and inserting ints when
copying into the alloca. This should fix the CanSROA assertion coming
out of Clang's regression test suite.

llvm-svn: 165931
This commit is contained in:
Chandler Carruth 2012-10-15 10:24:43 +00:00
parent 9d966a2002
commit 49c8eea3c0
2 changed files with 31 additions and 9 deletions
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34
llvm/lib/Transforms/Scalar/SROA.cpp
View File

@ -2717,9 +2717,9 @@ private:
// If this doesn't map cleanly onto the alloca type, and that type isn't
// a single value type, just emit a memcpy.
bool EmitMemCpy
= !VecTy && (BeginOffset != NewAllocaBeginOffset ||
EndOffset != NewAllocaEndOffset ||
!NewAI.getAllocatedType()->isSingleValueType());
= !VecTy && !IntTy && (BeginOffset != NewAllocaBeginOffset ||
EndOffset != NewAllocaEndOffset ||
!NewAI.getAllocatedType()->isSingleValueType());
// If we're just going to emit a memcpy, the alloca hasn't changed, and the
// size hasn't been shrunk based on analysis of the viable range, this is
@ -2741,14 +2741,23 @@ private:
if (Pass.DeadSplitInsts.insert(&II))
Pass.DeadInsts.push_back(&II);
bool IsVectorElement = VecTy && (BeginOffset > NewAllocaBeginOffset ||
EndOffset < NewAllocaEndOffset);
bool IsWholeAlloca = BeginOffset == NewAllocaBeginOffset &&
EndOffset == NewAllocaEndOffset;
bool IsVectorElement = VecTy && !IsWholeAlloca;
uint64_t Size = EndOffset - BeginOffset;
IntegerType *SubIntTy
= IntTy ? Type::getIntNTy(IntTy->getContext(), Size*8) : 0;
Type *OtherPtrTy = IsDest ? II.getRawSource()->getType()
: II.getRawDest()->getType();
if (!EmitMemCpy)
OtherPtrTy = IsVectorElement ? VecTy->getElementType()->getPointerTo()
: NewAI.getType();
if (!EmitMemCpy) {
if (IsVectorElement)
OtherPtrTy = VecTy->getElementType()->getPointerTo();
else if (IntTy && !IsWholeAlloca)
OtherPtrTy = SubIntTy->getPointerTo();
else
OtherPtrTy = NewAI.getType();
}
// Compute the other pointer, folding as much as possible to produce
// a single, simple GEP in most cases.
@ -2795,11 +2804,20 @@ private:
IRB.CreateAlignedLoad(SrcPtr, Align, getName(".copyload")),
getIndex(IRB, BeginOffset),
getName(".copyextract"));
} else if (IntTy && !IsWholeAlloca && !IsDest) {
Src = extractInteger(IRB, SubIntTy, BeginOffset);
} else {
Src = IRB.CreateAlignedLoad(SrcPtr, Align, II.isVolatile(),
getName(".copyload"));
}
if (IntTy && !IsWholeAlloca && IsDest) {
StoreInst *Store = insertInteger(IRB, Src, BeginOffset);
(void)Store;
DEBUG(dbgs() << " to: " << *Store << "\n");
return true;
}
if (IsVectorElement && IsDest) {
// We have to insert into a loaded copy before storing.
Src = IRB.CreateInsertElement(

6
llvm/test/Transforms/SROA/basictest.ll
View File

@ -1046,8 +1046,12 @@ entry:
; Or a memset of the whole thing.
call void @llvm.memset.p0i8.i64(i8* %0, i8 0, i64 8, i32 1, i1 false)
; Store to the high 32-bits...
; Write to the high 32-bits with a memcpy.
%X.sroa.0.4.raw_idx4.i = getelementptr inbounds i8* %0, i32 4
%d.raw = bitcast double* %d to i8*
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %X.sroa.0.4.raw_idx4.i, i8* %d.raw, i32 4, i32 1, i1 false)
; Store to the high 32-bits...
%X.sroa.0.4.cast5.i = bitcast i8* %X.sroa.0.4.raw_idx4.i to i32*
store i32 1072693248, i32* %X.sroa.0.4.cast5.i, align 4