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(X, Y))
Summary:
(select (icmp sgt x, -1), lshr (X, Y), ashr (X, Y)) -> ashr (X, Y))
(select (icmp slt x, 1), ashr (X, Y), lshr (X, Y)) -> ashr (X, Y))
Fixes PR41173
Alive proof by @lebedev.ri (thanks)
Name: PR41173
%cmp = icmp slt i32 %x, 1
%shr = lshr i32 %x, %y
%shr1 = ashr i32 %x, %y
%retval.0 = select i1 %cmp, i32 %shr1, i32 %shr
=>
%retval.0 = ashr i32 %x, %y
Optimization: PR41173
Done: 1
Optimization is correct!
Reviewers: lebedev.ri, spatel
Reviewed By: lebedev.ri
Subscribers: nikic, craig.topper, llvm-commits, lebedev.ri
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64285
llvm-svn: 365893
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