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author | Hans Wennborg <hans@hanshq.net> | 2017-09-15 18:40:26 +0000 |
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committer | Hans Wennborg <hans@hanshq.net> | 2017-09-15 18:40:26 +0000 |
commit | 534bfbd3ba82b4fe742563667f933f4e0a8ac9f0 (patch) | |
tree | 61c4d15a8b4f53d736e97caea905aee212686927 /llvm/utils/TableGen/CodeGenDAGPatterns.cpp | |
parent | ea857d4cb8922b046e1acadce494a2c6c9108cb4 (diff) | |
download | llvm-534bfbd3ba82b4fe742563667f933f4e0a8ac9f0.zip llvm-534bfbd3ba82b4fe742563667f933f4e0a8ac9f0.tar.gz llvm-534bfbd3ba82b4fe742563667f933f4e0a8ac9f0.tar.bz2 |
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
Diffstat (limited to 'llvm/utils/TableGen/CodeGenDAGPatterns.cpp')
0 files changed, 0 insertions, 0 deletions