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Fix incorrect partial aliasing

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Update testcases

llvm-svn: 227099
This commit is contained in:
Daniel Berlin 2015-01-26 17:31:17 +00:00
parent 96a67252fe
commit 97c2bb6967
4 changed files with 49 additions and 17 deletions
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27
lib/Analysis/CFLAliasAnalysis.cpp
View File

@ -298,8 +298,11 @@ public:
}
void visitSelectInst(SelectInst &Inst) {
auto *Condition = Inst.getCondition();
Output.push_back(Edge(&Inst, Condition, EdgeType::Assign, AttrNone));
// Condition is not processed here (The actual statement producing
// the condition result is processed elsewhere). For select, the
// condition is evaluated, but not loaded, stored, or assigned
// simply as a result of being the condition of a select.
auto *TrueVal = Inst.getTrueValue();
Output.push_back(Edge(&Inst, TrueVal, EdgeType::Assign, AttrNone));
auto *FalseVal = Inst.getFalseValue();
@ -771,7 +774,10 @@ static Optional<StratifiedAttr> valueToAttrIndex(Value *Val) {
return AttrGlobalIndex;
if (auto *Arg = dyn_cast<Argument>(Val))
if (!Arg->hasNoAliasAttr())
// Only pointer arguments should have the argument attribute,
// because things can't escape through scalars without us seeing a
// cast, and thus, interaction with them doesn't matter.
if (!Arg->hasNoAliasAttr() && Arg->getType()->isPointerTy())
return argNumberToAttrIndex(Arg->getArgNo());
return NoneType();
}
@ -994,10 +1000,6 @@ CFLAliasAnalysis::query(const AliasAnalysis::Location &LocA,
auto SetA = *MaybeA;
auto SetB = *MaybeB;
if (SetA.Index == SetB.Index)
return AliasAnalysis::PartialAlias;
auto AttrsA = Sets.getLink(SetA.Index).Attrs;
auto AttrsB = Sets.getLink(SetB.Index).Attrs;
// Stratified set attributes are used as markets to signify whether a member
@ -1012,5 +1014,16 @@ CFLAliasAnalysis::query(const AliasAnalysis::Location &LocA,
if (AttrsA.any() && AttrsB.any())
return AliasAnalysis::MayAlias;
// We currently unify things even if the accesses to them may not be in
// bounds, so we can't return partial alias here because we don't
// know whether the pointer is really within the object or not.
// IE Given an out of bounds GEP and an alloca'd pointer, we may
// unify the two. We can't return partial alias for this case.
// Since we do not currently track enough information to
// differentiate
if (SetA.Index == SetB.Index)
return AliasAnalysis::MayAlias;
return AliasAnalysis::NoAlias;
}

8
test/Analysis/CFLAliasAnalysis/full-store-partial-alias.ll
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@ -2,8 +2,9 @@
; RUN: opt -S -tbaa -gvn < %s | FileCheck %s
; Adapted from the BasicAA full-store-partial-alias.ll test.
; CFL AA should notice that the store stores to the entire %u object,
; CFL AA could notice that the store stores to the entire %u object,
; so the %tmp5 load is PartialAlias with the store and suppress TBAA.
; FIXME: However, right now, CFLAA cannot prove PartialAlias here
; Without CFL AA, TBAA should say that %tmp5 is NoAlias with the store.
target datalayout = "e-p:64:64:64"
@ -14,8 +15,9 @@ target datalayout = "e-p:64:64:64"
@endianness_test = global i64 1, align 8
define i32 @signbit(double %x) nounwind {
; CFLAA: ret i32 %tmp5.lobit
; CHECK: ret i32 0
; FIXME: This would be ret i32 %tmp5.lobit if CFLAA could prove PartialAlias
; CFLAA: ret i32 0
; CHECK: ret i32 0
entry:
%u = alloca %union.anon, align 8
%tmp9 = getelementptr inbounds %union.anon* %u, i64 0, i32 0

6
test/Analysis/CFLAliasAnalysis/gep-signed-arithmetic.ll
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@ -3,9 +3,11 @@
target datalayout = "e-p:32:32:32"
; CHECK: 1 partial alias response
; FIXME: This could be PartialAlias but CFLAA can't currently prove it
; CHECK: 1 may alias response
define i32 @test(i32* %tab, i32 %indvar) nounwind {
define i32 @test(i32 %indvar) nounwind {
%tab = alloca i32, align 4
%tmp31 = mul i32 %indvar, -2
%tmp32 = add i32 %tmp31, 30
%t.5 = getelementptr i32* %tab, i32 %tmp32

25
test/Analysis/CFLAliasAnalysis/must-and-partial.ll
View File

@ -1,14 +1,15 @@
; RUN: opt < %s -cfl-aa -aa-eval -print-all-alias-modref-info 2>&1 | FileCheck %s
; When merging MustAlias and PartialAlias, merge to PartialAlias
; instead of MayAlias.
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"
; CHECK: PartialAlias: i16* %bigbase0, i8* %phi
define i8 @test0(i8* %base, i1 %x) {
; FIXME: This could be PartialAlias but CFLAA can't currently prove it
; CHECK: MayAlias: i16* %bigbase0, i8* %phi
define i8 @test0(i1 %x) {
entry:
%base = alloca i8, align 4
%baseplusone = getelementptr i8* %base, i64 1
br i1 %x, label %red, label %green
red:
@ -24,9 +25,11 @@ green:
ret i8 %loaded
}
; CHECK: PartialAlias: i16* %bigbase1, i8* %sel
define i8 @test1(i8* %base, i1 %x) {
; FIXME: This could be PartialAlias but CFLAA can't currently prove it
; CHECK: MayAlias: i16* %bigbase1, i8* %sel
define i8 @test1(i1 %x) {
entry:
%base = alloca i8, align 4
%baseplusone = getelementptr i8* %base, i64 1
%sel = select i1 %x, i8* %baseplusone, i8* %base
store i8 0, i8* %sel
@ -37,3 +40,15 @@ entry:
%loaded = load i8* %sel
ret i8 %loaded
}
; Incoming pointer arguments should not be PartialAlias because we do not know their initial state
; even if they are nocapture
; CHECK: MayAlias: double* %A, double* %Index
define void @testr2(double* nocapture readonly %A, double* nocapture readonly %Index) {
%arrayidx22 = getelementptr inbounds double* %Index, i64 2
%1 = load double* %arrayidx22
%arrayidx25 = getelementptr inbounds double* %A, i64 2
%2 = load double* %arrayidx25
%mul26 = fmul double %1, %2
ret void
}