6ef4505298
This implements the most basic possible nosync inference. The choice of inference rule is taken from the comments in attributor and the discussion on the review of the change which introduced the nosync attribute (0626367202c). This is deliberately minimal. As noted in code comments, I do plan to add a more robust inference which actually scans the function IR directly, but a) I need to do some refactoring of the attributor code to use common interfaces, and b) I wanted to get something in. I also wanted to minimize the "interesting" analysis discussion since that's time intensive. Context: This combines with existing nofree attribute inference to help prove dereferenceability in the ongoing deref-at-point semantics work. Differential Revision: https://reviews.llvm.org/D99749
25 lines
858 B
LLVM
25 lines
858 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 = { norecurse nosync nounwind readnone ssp uwtable willreturn }
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; CHECK: attributes #1 = { nofree norecurse nounwind ssp uwtable willreturn }
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