a03eeb0e98
If this flag is set, Xor will not be considered AddLike. If an Xor were treated as an Add it may wrap. If we can prove there would be no carry out and thus no wrap, the Xor would be turned into a disjoint Or by DAGCombine. Use this new flag to fix a bug in X86 where an Xor is incorrectly being treated as an NUWAdd. Fixes #90668.
17 lines
481 B
LLVM
17 lines
481 B
LLVM
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 4
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; RUN: llc < %s -mtriple=x86_64-linux-gnu | FileCheck %s
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define i64 @off(i8 signext %a) {
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; CHECK-LABEL: off:
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; CHECK: # %bb.0: # %entry
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; CHECK-NEXT: addb $-128, %dil
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; CHECK-NEXT: movzbl %dil, %eax
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; CHECK-NEXT: shll $3, %eax
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; CHECK-NEXT: retq
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entry:
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%add = xor i8 %a, -128
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%conv2 = zext i8 %add to i64
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%mul = shl nuw nsw i64 %conv2, 3
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ret i64 %mul
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}
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