43d6991c2a
A logic incompleteness may lead MemorySSA to be too conservative in its results. Specifically, when dealing with a call of kind `call i32 bitcast (i1 (i1)* @test to i32 (i32)*)(i32 %1)`, where the function `test` is declared with readonly attribute, the bitcast is not looked through, obscuring function attributes. Hence, some methods of CallBase (e.g., doesNotReadMemory) could provide suboptimal results. Differential Revision: https://reviews.llvm.org/D109888
15 lines
591 B
LLVM
15 lines
591 B
LLVM
; RUN: opt -aa-pipeline=basic-aa -passes='print<memoryssa>,verify<memoryssa>' -disable-output < %s 2>&1 | FileCheck %s
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;
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; Ensures that MemorySSA leverages the ground truth of the function being called when wrapped in a bitcast.
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declare i1 @opaque_true(i1) nounwind readonly
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define i1 @foo(i32* %ptr, i1 %cond) {
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%cond_wide = zext i1 %cond to i32
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; CHECK: MemoryUse(liveOnEntry) MayAlias
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; CHECK-NEXT: call i32 bitcast
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%cond_hidden_wide = call i32 bitcast (i1 (i1)* @opaque_true to i32 (i32)*)(i32 %cond_wide)
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%cond_hidden = trunc i32 %cond_hidden_wide to i1
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ret i1 %cond_hidden
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}
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