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History

Sanjay Patel c1e0184317 [InstCombine] reduce even more unsigned saturated add with 'not' op

We want to use the sum in the icmp to allow matching with
m_UAddWithOverflow and eliminate the 'not'. This is discussed
in D51929 and is another step towards solving PR14613:
https://bugs.llvm.org/show_bug.cgi?id=14613

  Name: uaddsat, -1 fval
  %notx = xor i32 %x, -1
  %a = add i32 %x, %y
  %c = icmp ugt i32 %notx, %y
  %r = select i1 %c, i32 %a, i32 -1
  =>
  %a = add i32 %x, %y
  %c2 = icmp ugt i32 %y, %a
  %r = select i1 %c2, i32 -1, i32 %a

  Name: uaddsat, -1 fval + ult
  %notx = xor i32 %x, -1
  %a = add i32 %x, %y
  %c = icmp ult i32 %y, %notx
  %r = select i1 %c, i32 %a, i32 -1
  =>
  %a = add i32 %x, %y
  %c2 = icmp ugt i32 %y, %a
  %r = select i1 %c2, i32 -1, i32 %a

https://rise4fun.com/Alive/nTp

llvm-svn: 354393

2019-02-19 22:14:21 +00:00

CMakeLists.txt

[InstCombine] Optimize atomicrmw <op>, 0 into load atomic when possible

2019-02-07 21:27:23 +00:00

InstCombineAddSub.cpp

Update the file headers across all of the LLVM projects in the monorepo

2019-01-19 08:50:56 +00:00

InstCombineAndOrXor.cpp

[InstCombine] Fix matchRotate bug when one operand is a ConstantExpr shift

2019-02-11 19:26:27 +00:00

InstCombineAtomicRMW.cpp

[InstCombine] Address a couple stylistic issues pointed out by reviewer [NFC]