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[InstCombine] move add after smin/smax

Authored by spatel on Mar 2 2019, 8:45 AM.

Description

[InstCombine] move add after smin/smax

Follow-up to rL355221.
This isn't specifically called for within PR14613,
but we'll get there eventually if it's not already
requested in some other bug report.

https://rise4fun.com/Alive/5b0

Name: smax
Pre: WillNotOverflowSignedSub(C1,C0)
%a = add nsw i8 %x, C0
%cond = icmp sgt i8 %a, C1
%r = select i1 %cond, i8 %a, i8 C1
=>
%c2 = icmp sgt i8 %x, C1-C0
%u2 = select i1 %c2, i8 %x, i8 C1-C0
%r = add nsw i8 %u2, C0

Name: smin
Pre: WillNotOverflowSignedSub(C1,C0)
%a = add nsw i32 %x, C0
%cond = icmp slt i32 %a, C1
%r = select i1 %cond, i32 %a, i32 C1
=>
%c2 = icmp slt i32 %x, C1-C0
%u2 = select i1 %c2, i32 %x, i32 C1-C0
%r = add nsw i32 %u2, C0

llvm-svn: 355272

Details

Committed
spatelMar 2 2019, 8:45 AM
Parents
rG42ad8685c696: [InstCombine] add tests for add+smin/smax; NFC
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