c3f227ead6
When eliminating a tail call, we modify the values of the arguments. Therefore, if the byval parameter has a readonly attribute, we have to remove it. It is safe because, from the perspective of a caller, the byval parameter is always treated as "readonly," even if the readonly attribute is removed. Fixes #64289. Reviewed By: nikic Differential Revision: https://reviews.llvm.org/D156793
28 lines
771 B
LLVM
28 lines
771 B
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt -S -O3 < %s | FileCheck %s
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; A miscompilation found on https://github.com/llvm/llvm-project/issues/64289.
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; 1. PostOrderFunctionAttrsPass added readonly to the parameter.
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; 2. TailCallElimPass modified the parameter but kept readonly.
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; 3. LICMPass incorrectly hoisted the load instruction.
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define void @pr64289(ptr noalias byval(i64) %x) {
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; CHECK-LABEL: @pr64289(
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; CHECK-NEXT: start:
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; CHECK-NEXT: ret void
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;
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start:
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%new_x = alloca i64, align 8
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%x_val = load i64, ptr %x, align 8
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%is_zero = icmp eq i64 %x_val, 0
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br i1 %is_zero, label %end, label %recurse
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recurse:
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store i64 0, ptr %new_x, align 8
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call void @pr64289(ptr %new_x)
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br label %end
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end:
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ret void
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}
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