909ab0e0d1
Select blocks poison, but AND/OR do not. We need to insert a freeze to block poison propagation. This creates suboptimal codegen which I will try to fix with other patches. I'm prioritizing the correctness fix since we have 2 bug reports. Fixes #84200 and #84350
23 lines
735 B
LLVM
23 lines
735 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=riscv64 | FileCheck %s
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; The sub nuw produces poison if the input is not 0 or 1. We must insert a
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; freeze before converting the sub to AND so that we don't propagate poison.
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define i64 @foo(i64 %1) {
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; CHECK-LABEL: foo:
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; CHECK: # %bb.0: # %entry
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; CHECK-NEXT: li a1, 1
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; CHECK-NEXT: sub a1, a1, a0
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; CHECK-NEXT: sltiu a0, a0, 2
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; CHECK-NEXT: xori a1, a1, 1
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; CHECK-NEXT: neg a0, a0
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; CHECK-NEXT: and a0, a0, a1
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; CHECK-NEXT: ret
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entry:
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%.urem.i = sub nuw i64 1, %1
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%.cmp.i = icmp ugt i64 %1, 1
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%2 = xor i64 %.urem.i, 1
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%3 = select i1 %.cmp.i, i64 0, i64 %2
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ret i64 %3
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}
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