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path: root/llvm/test/Transforms/CodeGenPrepare/X86/memcmp.ll
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* [CGP, x86] update test checks; NFCSanjay Patel2017-07-061-38/+39
| | | | | | | | This was auto-generated using an older version of the script, and that version does not work with phis, so if we enable expansion it will go bad. llvm-svn: 307267
* [CGP] add specialization for memcmp expansion with only one basic blockSanjay Patel2017-06-271-90/+33
| | | | llvm-svn: 306485
* [CGP] eliminate a sub instruction in memcmp expansionSanjay Patel2017-06-271-30/+25
| | | | | | | | | | | | | | | | | | | | | | As noted in D34071, there are some IR optimization opportunities that could be handled by normal IR passes if this expansion wasn't happening so late in CGP. Regardless of that, it seems wasteful to knowingly produce suboptimal IR here, so I'm proposing this change: %s = sub i32 %x, %y %r = icmp ne %s, 0 => %r = icmp ne %x, %y Changing the predicate to 'eq' mimics what InstCombine would do, so that's just an efficiency improvement if we decide this expansion should happen sooner. The fact that the PowerPC backend doesn't eliminate the 'subf.' might be something for PPC folks to investigate separately. Differential Revision: https://reviews.llvm.org/D34416 llvm-svn: 306471
* [x86] set the datalayout to match the RUN line triple; NFCSanjay Patel2017-06-211-4/+2
| | | | | | | I don't think there's any visible difference from having the wrong layout for the 32-bit case at this point, but that could change in the future. llvm-svn: 305931
* [x86] enable CGP memcmp() expansion for 2/4/8 byte sizesSanjay Patel2017-06-201-18/+132
| | | | | | | | | There are a couple of potential improvements as seen in the IR and asm: 1. We're unnecessarily extending to a larger type to compare values. 2. The codegen for (select cond, 1, -1) could avoid a cmov. (or we could change the order of the compares, so we have a select with 0 operand) llvm-svn: 305802
* [CGP, x86] add tests for potential memcmp expansion; NFCSanjay Patel2017-06-081-0/+337
No IR tests were added with rL304313 ( https://reviews.llvm.org/D28637 ), so I want these for extra coverage if we enable memcmp expansion for x86. As shown, nothing is expanded for x86 in CGP yet. Also fundamentally, we're doing an IR transform, so we should have IR tests for just that part. If something goes wrong, we need to know if the bug is in CGP or later lowering. llvm-svn: 305011
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