Thumb1 does not support dynamic stack realignment.

rdar://10288916 is tracking this fix.

In the past, instcombine and other passes were promoting alloca alignment past
the natural alignment, resulting in dynamic stack realignment.  Lang's work now
prevents this from happening (LLVM commit r141599).  Now that this really 
shouldn't happen report a fatal error rather than silently generate bad code.

llvm-svn: 142028
This commit is contained in:
Chad Rosier 2011-10-15 00:28:24 +00:00
parent 9c1019c6c7
commit 1809d6c0d5
1 changed files with 5 additions and 0 deletions

View File

@ -155,6 +155,11 @@ void Thumb1FrameLowering::emitPrologue(MachineFunction &MF) const {
AFI->setGPRCalleeSavedArea2Size(GPRCS2Size);
AFI->setDPRCalleeSavedAreaSize(DPRCSSize);
// Thumb1 does not currently support dynamic stack realignment. Report a
// fatal error rather then silently generate bad code.
if (RegInfo->needsStackRealignment(MF))
report_fatal_error("Dynamic stack realignment not supported for thumb1.");
// If we need a base pointer, set it up here. It's whatever the value
// of the stack pointer is at this point. Any variable size objects
// will be allocated after this, so we can still use the base pointer