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Pull in r192064 from upstream llvm trunk:

X86: Don't fold spills into SSE operations if the stack is unaligned.

  Regalloc can emit unaligned spills nowadays, but we can't fold the
  spills into SSE ops if we can't guarantee alignment. PR12250.

This fixes unaligned SSE accesses (leading to a SIGBUS) which could
occur in the ffmpeg ports.

Approved by:	re (kib)
Reported by:	tijl
MFC after:	3 days
This commit is contained in:
Dimitry Andric 2013-10-06 16:12:45 +00:00
parent 5dc5cbb274
commit 7ae3e01a31
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=256090

View File

@ -3881,6 +3881,10 @@ MachineInstr* X86InstrInfo::foldMemoryOperandImpl(MachineFunction &MF,
const MachineFrameInfo *MFI = MF.getFrameInfo();
unsigned Size = MFI->getObjectSize(FrameIndex);
unsigned Alignment = MFI->getObjectAlignment(FrameIndex);
// If the function stack isn't realigned we don't want to fold instructions
// that need increased alignment.
if (!RI.needsStackRealignment(MF))
Alignment = std::min(Alignment, TM.getFrameLowering()->getStackAlignment());
if (Ops.size() == 2 && Ops[0] == 0 && Ops[1] == 1) {
unsigned NewOpc = 0;
unsigned RCSize = 0;