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bf301d5670
This provides an implementation of CFL alias analysis (including some supporting data structures). Currently, we don't have any extremely fancy features, sans some interprocedural analysis (i.e. no field sensitivity, etc.), and we do best sitting behind BasicAA + TBAA. In such a configuration, we take ~0.6-0.8% of total compile time, and give ~7-8% NoAlias responses to queries TBAA and BasicAA couldn't answer when bootstrapping LLVM. In testing this on other projects, we've seen up to 10.5% of queries dropped by BasicAA+TBAA answered with NoAlias by this algorithm. Patch by George Burgess IV (with minor modifications by me -- mostly adapting some BasicAA tests), thanks! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216970 91177308-0d34-0410-b5e6-96231b3b80d8
40 lines
1.1 KiB
LLVM
40 lines
1.1 KiB
LLVM
; RUN: opt < %s -cfl-aa -aa-eval -print-all-alias-modref-info 2>&1 | FileCheck %s
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; When merging MustAlias and PartialAlias, merge to PartialAlias
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; instead of MayAlias.
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target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
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; CHECK: PartialAlias: i16* %bigbase0, i8* %phi
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define i8 @test0(i8* %base, i1 %x) {
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entry:
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%baseplusone = getelementptr i8* %base, i64 1
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br i1 %x, label %red, label %green
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red:
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br label %green
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green:
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%phi = phi i8* [ %baseplusone, %red ], [ %base, %entry ]
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store i8 0, i8* %phi
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%bigbase0 = bitcast i8* %base to i16*
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store i16 -1, i16* %bigbase0
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%loaded = load i8* %phi
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ret i8 %loaded
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}
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; CHECK: PartialAlias: i16* %bigbase1, i8* %sel
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define i8 @test1(i8* %base, i1 %x) {
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entry:
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%baseplusone = getelementptr i8* %base, i64 1
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%sel = select i1 %x, i8* %baseplusone, i8* %base
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store i8 0, i8* %sel
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%bigbase1 = bitcast i8* %base to i16*
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store i16 -1, i16* %bigbase1
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%loaded = load i8* %sel
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ret i8 %loaded
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}
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