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[InstCombine] (-NSW x) u< x --> x s< 0 (PR39480)

Authored by lebedev.ri on Aug 6 2020, 1:26 AM.

Description

[InstCombine] (-NSW x) u< x --> x s< 0 (PR39480)

Name: (-x) u< x --> x s< 0
%neg_x = sub nsw i8 0, %x ; %x must not be INT_MIN
%r = icmp ult i8 %neg_x, %x

=>

%r = icmp slt i8 %x, 0

https://rise4fun.com/Alive/zSuf

https://bugs.llvm.org/show_bug.cgi?id=39480

Details

Committed
lebedev.riAug 6 2020, 1:50 AM
Parents
rG0e1241a3c988: [InstCombine] (-NSW x) u>= x --> x s>= 0 (PR39480)
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