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path: root/lib/CodeGen/MachineCopyPropagation.cpp
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2012-01-08Avoid eraseing copies from a reserved register unless the definition can beEvan Cheng
safely proven not to have been clobbered. No small test case possible. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147751 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-07Added a late machine instruction copy propagation pass. This catchesEvan Cheng
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 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147716 91177308-0d34-0410-b5e6-96231b3b80d8