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authorHans Wennborg <hans@hanshq.net>2017-09-15 18:40:26 +0000
committerHans Wennborg <hans@hanshq.net>2017-09-15 18:40:26 +0000
commit534bfbd3ba82b4fe742563667f933f4e0a8ac9f0 (patch)
tree61c4d15a8b4f53d736e97caea905aee212686927 /llvm/utils/TableGen/CodeGenDAGPatterns.cpp
parentea857d4cb8922b046e1acadce494a2c6c9108cb4 (diff)
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Revert r313343 "[X86] PR32755 : Improvement in CodeGen instruction selection for LEAs."
This caused PR34629: asserts firing when building Chromium. It also broke some buildbots building test-suite as reported on the commit thread. > Summary: > 1/ Operand folding during complex pattern matching for LEAs has been > extended, such that it promotes Scale to accommodate similar operand > appearing in the DAG. > e.g. > T1 = A + B > T2 = T1 + 10 > T3 = T2 + A > For above DAG rooted at T3, X86AddressMode will no look like > Base = B , Index = A , Scale = 2 , Disp = 10 > > 2/ During OptimizeLEAPass down the pipeline factorization is now performed over LEAs > so that if there is an opportunity then complex LEAs (having 3 operands) > could be factored out. > e.g. > leal 1(%rax,%rcx,1), %rdx > leal 1(%rax,%rcx,2), %rcx > will be factored as following > leal 1(%rax,%rcx,1), %rdx > leal (%rdx,%rcx) , %edx > > 3/ Aggressive operand folding for AM based selection for LEAs is sensitive to loops, > thus avoiding creation of any complex LEAs within a loop. > > Reviewers: lsaba, RKSimon, craig.topper, qcolombet > > Reviewed By: lsaba > > Subscribers: spatel, igorb, llvm-commits > > Differential Revision: https://reviews.llvm.org/D35014 llvm-svn: 313376
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