llvm /
llvm /
7e06b426b60c161e25dece3cf157119a64855f46 [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
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@354276 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed
