3 Commits

Author	SHA1	Message	Date
Hans Wennborg	8eb336c14e	Re-commit r269828 "X86: Avoid using _chkstk when lowering WIN_ALLOCA instructions" ... with an additional fix to make RegAllocFast ignore undef physreg uses. It would previously get confused about the "push %eax" instruction's use of eax. That method for adjusting the stack pointer is used in X86FrameLowering::emitSPUpdate as well, but since that runs after register-allocation, we didn't run into the RegAllocFast issue before. llvm-svn: 269949	2016-05-18 16:10:17 +00:00
Hans Wennborg	759af30109	Revert r269828 "X86: Avoid using _chkstk when lowering WIN_ALLOCA instructions" ... Seems to have broken the Windows ASan bot. Reverting while investigating. llvm-svn: 269833	2016-05-17 20:38:56 +00:00
Hans Wennborg	c3fb51171e	X86: Avoid using _chkstk when lowering WIN_ALLOCA instructions ... This patch moves the expansion of WIN_ALLOCA pseudo-instructions into a separate pass that walks the CFG and lowers the instructions based on a conservative estimate of the offset between the stack pointer and the lowest accessed stack address. The goal is to reduce binary size and run-time costs by removing calls to _chkstk. While it doesn't fix all the code quality problems with inalloca calls, it's an incremental improvement for PR27076. Differential Revision: http://reviews.llvm.org/D20263 llvm-svn: 269828	2016-05-17 20:13:29 +00:00