[PATCH] D46031: [DAGCombiner] Masked merge: if 'B' is constant, de-canonicalize the pattern (invert the mask).
Sanjay Patel via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Wed May 2 11:11:01 PDT 2018
spatel added inline comments.
================
Comment at: test/CodeGen/AArch64/unfold-masked-merge-scalar-variablemask.ll:350-355
-; CHECK-NEXT: and w8, w0, w2
-; CHECK-NEXT: orn w0, w8, w2
+; CHECK-NEXT: mvn w8, w0
+; CHECK-NEXT: bic w8, w8, w2
+; CHECK-NEXT: orr w0, w8, w0
; CHECK-NEXT: ret
%n0 = xor i32 %x, -1 ; %x
%n1 = and i32 %n0, %mask
%r = xor i32 %n1, -1
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How does this happen? Isn't that a miscompile?
Repository:
rL LLVM
https://reviews.llvm.org/D46031
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