3 Commits

Author	SHA1	Message	Date
Jakob Stoklund Olesen	8c139a5125	Clear kill flags before propagating a copy. ... The live range of the source register may be extended when a redundant copy is eliminated. Make sure any kill flags between the two copies are cleared. This fixes PR11765. llvm-svn: 149069	2012-01-26 17:52:15 +00:00
Evan Cheng	520730ff23	Avoid eraseing copies from a reserved register unless the definition can be ... safely proven not to have been clobbered. No small test case possible. llvm-svn: 147751	2012-01-08 19:52:28 +00:00
Evan Cheng	00b1a3cd7e	Added a late machine instruction copy propagation pass. This catches ... opportunities that only present themselves after late optimizations such as tail duplication .e.g. ## BB#1: movl %eax, %ecx movl %ecx, %eax ret The register allocator also leaves some of them around (due to false dep between copies from phi-elimination, etc.) This required some changes in codegen passes. Post-ra scheduler and the pseudo-instruction expansion passes have been moved after branch folding and tail merging. They were before branch folding before because it did not always update block livein's. That's fixed now. The pass change makes independently since we want to properly schedule instructions after branch folding / tail duplication. rdar://10428165 rdar://10640363 llvm-svn: 147716	2012-01-07 03:02:36 +00:00