e5822ded56
This patch adds initial argmemonly inference, by checking the underlying
objects of locations returned by MemoryLocation.
I think this should cover most cases, except function calls to other
argmemonly functions.
I'm not sure if there's a reason why we don't infer those yet.
Additional argmemonly can improve codegen in some cases. It also makes
it easier to come up with a C reproducer for 7662d1687b (already fixed,
but I'm trying to see if C/C++ fuzzing could help to uncover similar
issues.)
Compile-time impact:
NewPM-O3: +0.01%
NewPM-ReleaseThinLTO: +0.03%
NewPM-ReleaseLTO+g: +0.05%
https://llvm-compile-time-tracker.com/compare.php?from=067c035012fc061ad6378458774ac2df117283c6&to=fe209d4aab5b593bd62d18c0876732ddcca1614d&stat=instructions
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D121415
25 lines
902 B
LLVM
25 lines
902 B
LLVM
; RUN: opt -basic-aa -function-attrs -S < %s | FileCheck %s
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; RUN: opt -aa-pipeline=basic-aa -passes=function-attrs -S < %s | FileCheck %s
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; Atomic load/store to local doesn't affect whether a function is
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; readnone/readonly.
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define i32 @test1(i32 %x) uwtable ssp {
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; CHECK: define i32 @test1(i32 %x) #0 {
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entry:
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%x.addr = alloca i32, align 4
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store atomic i32 %x, i32* %x.addr seq_cst, align 4
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%r = load atomic i32, i32* %x.addr seq_cst, align 4
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ret i32 %r
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}
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; A function with an Acquire load is not readonly.
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define i32 @test2(i32* %x) uwtable ssp {
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; CHECK: define i32 @test2(i32* nocapture readonly %x) #1 {
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entry:
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%r = load atomic i32, i32* %x seq_cst, align 4
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ret i32 %r
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}
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; CHECK: attributes #0 = { mustprogress nofree norecurse nosync nounwind readnone ssp willreturn uwtable }
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; CHECK: attributes #1 = { argmemonly mustprogress nofree norecurse nounwind ssp willreturn uwtable }
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