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Infer alignments of fixed frame objects when they are constructed. This ensures remat'ed loads from fixed slots have the right alignments.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107591 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2010-07-04 18:52:05 +00:00
parent aa6c855c8e
commit f2f4903687
2 changed files with 7 additions and 18 deletions
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8
lib/CodeGen/MachineFunction.cpp
View File

@ -440,7 +440,13 @@ MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
bool Immutable) {
assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset, Immutable,
// The alignment of the frame index can be determined from its offset from
// the incoming frame position. If the frame object is at offset 32 and
// the stack is guaranteed to be 16-byte aligned, then we know that the
// object is 16-byte aligned.
unsigned StackAlign = TFI.getStackAlignment();
unsigned Align = MinAlign(SPOffset, StackAlign);
Objects.insert(Objects.begin(), StackObject(Size, Align, SPOffset, Immutable,
/*isSS*/false));
return -++NumFixedObjects;
}

17
lib/CodeGen/SelectionDAG/SelectionDAG.cpp
View File

@ -6262,23 +6262,6 @@ unsigned SelectionDAG::InferPtrAlignment(SDValue Ptr) const {
const MachineFrameInfo &MFI = *getMachineFunction().getFrameInfo();
unsigned FIInfoAlign = MinAlign(MFI.getObjectAlignment(FrameIdx),
FrameOffset);
if (MFI.isFixedObjectIndex(FrameIdx)) {
int64_t ObjectOffset = MFI.getObjectOffset(FrameIdx) + FrameOffset;
// The alignment of the frame index can be determined from its offset from
// the incoming frame position. If the frame object is at offset 32 and
// the stack is guaranteed to be 16-byte aligned, then we know that the
// object is 16-byte aligned.
unsigned StackAlign = getTarget().getFrameInfo()->getStackAlignment();
unsigned Align = MinAlign(ObjectOffset, StackAlign);
// Finally, the frame object itself may have a known alignment. Factor
// the alignment + offset into a new alignment. For example, if we know
// the FI is 8 byte aligned, but the pointer is 4 off, we really have a
// 4-byte alignment of the resultant pointer. Likewise align 4 + 4-byte
// offset = 4-byte alignment, align 4 + 1-byte offset = align 1, etc.
return std::max(Align, FIInfoAlign);
}
return FIInfoAlign;
}