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https://github.com/c64scene-ar/llvm-6502.git
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When merging MustAlias and PartialAlias, chose PartialAlias instead
of conservatively choosing MayAlias. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132579 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
@ -949,6 +949,19 @@ BasicAliasAnalysis::aliasGEP(const GEPOperator *GEP1, uint64_t V1Size,
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return MayAlias;
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return MayAlias;
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}
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}
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static AliasAnalysis::AliasResult
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MergeAliasResults(AliasAnalysis::AliasResult A, AliasAnalysis::AliasResult B) {
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// If the results agree, take it.
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if (A == B)
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return A;
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// A mix of PartialAlias and MustAlias is PartialAlias.
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if ((A == AliasAnalysis::PartialAlias && B == AliasAnalysis::MustAlias) ||
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(B == AliasAnalysis::PartialAlias && A == AliasAnalysis::MustAlias))
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return AliasAnalysis::PartialAlias;
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// Otherwise, we don't know anything.
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return AliasAnalysis::MayAlias;
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}
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/// aliasSelect - Provide a bunch of ad-hoc rules to disambiguate a Select
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/// aliasSelect - Provide a bunch of ad-hoc rules to disambiguate a Select
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/// instruction against another.
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/// instruction against another.
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AliasAnalysis::AliasResult
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AliasAnalysis::AliasResult
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@ -975,9 +988,7 @@ BasicAliasAnalysis::aliasSelect(const SelectInst *SI, uint64_t SISize,
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AliasResult ThisAlias =
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AliasResult ThisAlias =
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aliasCheck(SI->getFalseValue(), SISize, SITBAAInfo,
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aliasCheck(SI->getFalseValue(), SISize, SITBAAInfo,
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SI2->getFalseValue(), V2Size, V2TBAAInfo);
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SI2->getFalseValue(), V2Size, V2TBAAInfo);
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if (ThisAlias != Alias)
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return MergeAliasResults(ThisAlias, Alias);
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return MayAlias;
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return Alias;
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}
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}
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// If both arms of the Select node NoAlias or MustAlias V2, then returns
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// If both arms of the Select node NoAlias or MustAlias V2, then returns
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@ -994,9 +1005,7 @@ BasicAliasAnalysis::aliasSelect(const SelectInst *SI, uint64_t SISize,
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AliasResult ThisAlias =
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AliasResult ThisAlias =
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aliasCheck(V2, V2Size, V2TBAAInfo, SI->getFalseValue(), SISize, SITBAAInfo);
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aliasCheck(V2, V2Size, V2TBAAInfo, SI->getFalseValue(), SISize, SITBAAInfo);
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if (ThisAlias != Alias)
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return MergeAliasResults(ThisAlias, Alias);
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return MayAlias;
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return Alias;
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}
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}
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// aliasPHI - Provide a bunch of ad-hoc rules to disambiguate a PHI instruction
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// aliasPHI - Provide a bunch of ad-hoc rules to disambiguate a PHI instruction
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@ -1026,8 +1035,9 @@ BasicAliasAnalysis::aliasPHI(const PHINode *PN, uint64_t PNSize,
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aliasCheck(PN->getIncomingValue(i), PNSize, PNTBAAInfo,
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aliasCheck(PN->getIncomingValue(i), PNSize, PNTBAAInfo,
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PN2->getIncomingValueForBlock(PN->getIncomingBlock(i)),
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PN2->getIncomingValueForBlock(PN->getIncomingBlock(i)),
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V2Size, V2TBAAInfo);
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V2Size, V2TBAAInfo);
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if (ThisAlias != Alias)
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Alias = MergeAliasResults(ThisAlias, Alias);
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return MayAlias;
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if (Alias == MayAlias)
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break;
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}
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}
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return Alias;
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return Alias;
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}
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}
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@ -1065,8 +1075,9 @@ BasicAliasAnalysis::aliasPHI(const PHINode *PN, uint64_t PNSize,
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AliasResult ThisAlias = aliasCheck(V2, V2Size, V2TBAAInfo,
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AliasResult ThisAlias = aliasCheck(V2, V2Size, V2TBAAInfo,
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V, PNSize, PNTBAAInfo);
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V, PNSize, PNTBAAInfo);
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if (ThisAlias != Alias || ThisAlias == MayAlias)
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Alias = MergeAliasResults(ThisAlias, Alias);
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return MayAlias;
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if (Alias == MayAlias)
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break;
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}
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}
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return Alias;
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return Alias;
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39
test/Analysis/BasicAA/must-and-partial.ll
Normal file
39
test/Analysis/BasicAA/must-and-partial.ll
Normal file
@ -0,0 +1,39 @@
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; RUN: opt < %s -basicaa -aa-eval -print-all-alias-modref-info |& 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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