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| author | Sanjay Patel <spatel@rotateright.com> | 2017-01-13 23:25:46 +0000 |
|---|---|---|
| committer | Sanjay Patel <spatel@rotateright.com> | 2017-01-13 23:25:46 +0000 |
| commit | 40f401776b3837b2d0f42517777fbb6d1de82413 (patch) | |
| tree | 8da7450cee1d7d665d0f2bf384e07218e29f74af /llvm/lib/CodeGen/ResetMachineFunctionPass.cpp | |
| parent | e61f9f9949a435d8396613b46c6ed7b65d61602b (diff) | |
| download | llvm-40f401776b3837b2d0f42517777fbb6d1de82413.zip llvm-40f401776b3837b2d0f42517777fbb6d1de82413.tar.gz llvm-40f401776b3837b2d0f42517777fbb6d1de82413.tar.bz2 | |
[InstCombine] optimize unsigned icmp of increment
Allows LLVM to optimize sequences like the following:
%add = add nuw i32 %x, 1
%cmp = icmp ugt i32 %add, %y
Into:
%cmp = icmp uge i32 %x, %y
Previously, only signed comparisons were being handled.
Decrements could also be handled, but 'sub nuw %x, 1' is currently canonicalized to
'add %x, -1' in InstCombineAddSub, losing the nuw flag. Removing that canonicalization
seems like it might have far-reaching ramifications so I kept this simple for now.
Patch by Matti Niemenmaa!
Differential Revision: https://reviews.llvm.org/D24700
llvm-svn: 291975
Diffstat (limited to 'llvm/lib/CodeGen/ResetMachineFunctionPass.cpp')
0 files changed, 0 insertions, 0 deletions