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[Lint] Permit aliasing noalias readonly arguments
Summary: If two arguments are both readonly, then they have no memory dependency that would violate noalias, even if they do actually overlap. Reviewers: hfinkel, efriedma Reviewed By: efriedma Subscribers: efriedma, hiraditya, llvm-commits, tstellar Tags: #llvm Differential Revision: https://reviews.llvm.org/D60239 llvm-svn: 359047
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Original file line number | Diff line number | Diff line change |
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; RUN: opt < %s -lint -disable-output 2>&1 | FileCheck %s | ||
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declare void @f1(i8* noalias readonly, i8*) | ||
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define void @f2(i8* %a) { | ||
entry: | ||
call void @f1(i8* %a, i8* %a) | ||
ret void | ||
} | ||
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; Lint should complain about us passing %a to both arguments, since the noalias | ||
; argument may depend on writes to the other. | ||
; CHECK: Unusual: noalias argument aliases another argument | ||
; CHECK-NEXT: call void @f1(i8* %a, i8* %a) | ||
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declare void @f3(i8* noalias, i8* readonly) | ||
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define void @f4(i8* %a) { | ||
entry: | ||
call void @f3(i8* %a, i8* %a) | ||
ret void | ||
} | ||
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; Lint should complain about us passing %a to both arguments, since writes to | ||
; the noalias argument may cause a dependency for the other. | ||
; CHECK: Unusual: noalias argument aliases another argument | ||
; CHECK-NEXT: call void @f3(i8* %a, i8* %a) | ||
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declare void @f5(i8* noalias readonly, i8* readonly) | ||
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define void @f6(i8* %a) { | ||
entry: | ||
call void @f5(i8* %a, i8* %a) | ||
ret void | ||
} | ||
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; Lint should not complain about passing %a to both arguments even if one is | ||
; noalias, since they are both readonly and thus have no dependence. | ||
; CHECK-NOT: Unusual: noalias argument aliases another argument | ||
; CHECK-NOT: call void @f5(i8* %a, i8* %a) |