forked from OSchip/llvm-project
[BasicAA] Revert r221876 because it can produce incorrect aliasing
information: see PR24468. llvm-svn: 245394
This commit is contained in:
Quentin Colombet
parent
8f2a7feec8
commit
b700e357b5
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@ -190,14 +190,6 @@ static bool isObjectSize(const Value *V, uint64_t Size, const DataLayout &DL,
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return V;
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}
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if (ConstantInt *Const = dyn_cast<ConstantInt>(V)) {
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// if it's a constant, just convert it to an offset
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// and remove the variable.
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Offset += Const->getValue();
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assert(Scale == 0 && "Constant values don't have a scale");
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return V;
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}
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if (BinaryOperator *BOp = dyn_cast<BinaryOperator>(V)) {
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if (ConstantInt *RHSC = dyn_cast<ConstantInt>(BOp->getOperand(1))) {
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switch (BOp->getOpcode()) {
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@ -246,10 +238,7 @@ static bool isObjectSize(const Value *V, uint64_t Size, const DataLayout &DL,
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Value *Result = GetLinearExpression(CastOp, Scale, Offset, Extension, DL,
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Depth + 1, AC, DT);
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Scale = Scale.zext(OldWidth);
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// We have to sign-extend even if Extension == EK_ZeroExt as we can't
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// decompose a sign extension (i.e. zext(x - 1) != zext(x) - zext(-1)).
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Offset = Offset.sext(OldWidth);
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Offset = Offset.zext(OldWidth);
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return Result;
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}
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@ -959,42 +948,12 @@ AliasResult BasicAliasAnalysis::aliasGEP(
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}
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}
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// Try to distinguish something like &A[i][1] against &A[42][0].
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// Grab the least significant bit set in any of the scales.
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if (!GEP1VariableIndices.empty()) {
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uint64_t Modulo = 0;
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bool AllPositive = true;
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for (unsigned i = 0, e = GEP1VariableIndices.size(); i != e; ++i) {
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// Try to distinguish something like &A[i][1] against &A[42][0].
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// Grab the least significant bit set in any of the scales. We
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// don't need std::abs here (even if the scale's negative) as we'll
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// be ^'ing Modulo with itself later.
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for (unsigned i = 0, e = GEP1VariableIndices.size(); i != e; ++i)
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Modulo |= (uint64_t)GEP1VariableIndices[i].Scale;
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if (AllPositive) {
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// If the Value could change between cycles, then any reasoning about
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// the Value this cycle may not hold in the next cycle. We'll just
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// give up if we can't determine conditions that hold for every cycle:
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const Value *V = GEP1VariableIndices[i].V;
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bool SignKnownZero, SignKnownOne;
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ComputeSignBit(const_cast<Value *>(V), SignKnownZero, SignKnownOne, *DL,
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0, AC1, nullptr, DT);
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// Zero-extension widens the variable, and so forces the sign
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// bit to zero.
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bool IsZExt = GEP1VariableIndices[i].Extension == EK_ZeroExt;
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SignKnownZero |= IsZExt;
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SignKnownOne &= !IsZExt;
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// If the variable begins with a zero then we know it's
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// positive, regardless of whether the value is signed or
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// unsigned.
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int64_t Scale = GEP1VariableIndices[i].Scale;
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AllPositive =
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(SignKnownZero && Scale >= 0) || (SignKnownOne && Scale < 0);
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}
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}
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Modulo = Modulo ^ (Modulo & (Modulo - 1));
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// We can compute the difference between the two addresses
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@ -1005,12 +964,6 @@ AliasResult BasicAliasAnalysis::aliasGEP(
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V2Size != MemoryLocation::UnknownSize && ModOffset >= V2Size &&
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V1Size <= Modulo - ModOffset)
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return NoAlias;
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// If we know all the variables are positive, then GEP1 >= GEP1BasePtr.
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// If GEP1BasePtr > V2 (GEP1BaseOffset > 0) then we know the pointers
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// don't alias if V2Size can fit in the gap between V2 and GEP1BasePtr.
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if (AllPositive && GEP1BaseOffset > 0 && V2Size <= (uint64_t)GEP1BaseOffset)
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return NoAlias;
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}
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// Statically, we can see that the base objects are the same, but the
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@ -39,7 +39,6 @@ return:
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; CHECK-LABEL: pr18068
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; CHECK: MayAlias: i32* %0, i32* %arrayidx5
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; CHECK: NoAlias: i32* %arrayidx13, i32* %arrayidx5
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define i32 @pr18068(i32* %jj7, i32* %j) {
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entry:
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@ -1,209 +0,0 @@
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; RUN: opt < %s -basicaa -aa-eval -print-all-alias-modref-info -disable-output 2>&1 | FileCheck %s
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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-S128"
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target triple = "x86_64-unknown-linux-gnu"
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; CHECK-LABEL: test_with_zext
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; CHECK: NoAlias: i8* %a, i8* %b
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define void @test_with_zext() {
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%1 = tail call i8* @malloc(i64 120)
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%a = getelementptr inbounds i8, i8* %1, i64 8
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%2 = getelementptr inbounds i8, i8* %1, i64 16
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%3 = zext i32 3 to i64
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%b = getelementptr inbounds i8, i8* %2, i64 %3
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ret void
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}
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; CHECK-LABEL: test_with_lshr
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; CHECK: NoAlias: i8* %a, i8* %b
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define void @test_with_lshr(i64 %i) {
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%1 = tail call i8* @malloc(i64 120)
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%a = getelementptr inbounds i8, i8* %1, i64 8
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%2 = getelementptr inbounds i8, i8* %1, i64 16
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%3 = lshr i64 %i, 2
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%b = getelementptr inbounds i8, i8* %2, i64 %3
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ret void
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}
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; CHECK-LABEL: test_with_a_loop
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; CHECK: NoAlias: i8* %a, i8* %b
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define void @test_with_a_loop(i8* %mem) {
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br label %for.loop
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for.loop:
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%i = phi i32 [ 0, %0 ], [ %i.plus1, %for.loop ]
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%a = getelementptr inbounds i8, i8* %mem, i64 8
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%a.plus1 = getelementptr inbounds i8, i8* %mem, i64 16
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%i.64 = zext i32 %i to i64
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%b = getelementptr inbounds i8, i8* %a.plus1, i64 %i.64
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%i.plus1 = add nuw nsw i32 %i, 1
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%cmp = icmp eq i32 %i.plus1, 10
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br i1 %cmp, label %for.loop.exit, label %for.loop
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for.loop.exit:
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ret void
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}
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; CHECK-LABEL: test_with_varying_base_pointer_in_loop
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; CHECK: NoAlias: i8* %a, i8* %b
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define void @test_with_varying_base_pointer_in_loop(i8* %mem.orig) {
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br label %for.loop
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for.loop:
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%mem = phi i8* [ %mem.orig, %0 ], [ %mem.plus1, %for.loop ]
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%i = phi i32 [ 0, %0 ], [ %i.plus1, %for.loop ]
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%a = getelementptr inbounds i8, i8* %mem, i64 8
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%a.plus1 = getelementptr inbounds i8, i8* %mem, i64 16
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%i.64 = zext i32 %i to i64
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%b = getelementptr inbounds i8, i8* %a.plus1, i64 %i.64
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%i.plus1 = add nuw nsw i32 %i, 1
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%mem.plus1 = getelementptr inbounds i8, i8* %mem, i64 8
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%cmp = icmp eq i32 %i.plus1, 10
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br i1 %cmp, label %for.loop.exit, label %for.loop
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for.loop.exit:
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ret void
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}
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; CHECK-LABEL: test_sign_extension
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; CHECK: PartialAlias: i64* %b.i64, i8* %a
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define void @test_sign_extension(i32 %p) {
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%1 = tail call i8* @malloc(i64 120)
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%p.64 = zext i32 %p to i64
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%a = getelementptr inbounds i8, i8* %1, i64 %p.64
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%p.minus1 = add i32 %p, -1
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%p.minus1.64 = zext i32 %p.minus1 to i64
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%b.i8 = getelementptr inbounds i8, i8* %1, i64 %p.minus1.64
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%b.i64 = bitcast i8* %b.i8 to i64*
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ret void
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}
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; CHECK-LABEL: test_fe_tools
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; CHECK: PartialAlias: i32* %a, i32* %b
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define void @test_fe_tools([8 x i32]* %values) {
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br label %reorder
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for.loop:
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%i = phi i32 [ 0, %reorder ], [ %i.next, %for.loop ]
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%idxprom = zext i32 %i to i64
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%b = getelementptr inbounds [8 x i32], [8 x i32]* %values, i64 0, i64 %idxprom
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%i.next = add nuw nsw i32 %i, 1
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%1 = icmp eq i32 %i.next, 10
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br i1 %1, label %for.loop.exit, label %for.loop
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reorder:
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%a = getelementptr inbounds [8 x i32], [8 x i32]* %values, i64 0, i64 1
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br label %for.loop
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for.loop.exit:
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ret void
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}
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@b = global i32 0, align 4
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@d = global i32 0, align 4
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; CHECK-LABEL: test_spec2006
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; CHECK: PartialAlias: i32** %x, i32** %y
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define void @test_spec2006() {
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%h = alloca [1 x [2 x i32*]], align 16
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%d.val = load i32, i32* @d, align 4
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%d.promoted = sext i32 %d.val to i64
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%1 = icmp slt i32 %d.val, 2
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br i1 %1, label %.lr.ph, label %3
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.lr.ph: ; preds = %0
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br label %2
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; <label>:2 ; preds = %.lr.ph, %2
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%i = phi i32 [ %d.val, %.lr.ph ], [ %i.plus1, %2 ]
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%i.promoted = sext i32 %i to i64
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%x = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 %d.promoted, i64 %i.promoted
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%i.plus1 = add nsw i32 %i, 1
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%cmp = icmp slt i32 %i.plus1, 2
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br i1 %cmp, label %2, label %3
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; <label>:3 ; preds = %._crit_edge, %0
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%y = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 0, i64 1
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ret void
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}
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; CHECK-LABEL: test_modulo_analysis_easy_case
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; CHECK: NoAlias: i32** %x, i32** %y
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define void @test_modulo_analysis_easy_case(i64 %i) {
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%h = alloca [1 x [2 x i32*]], align 16
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%x = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 %i, i64 0
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%y = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 0, i64 1
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ret void
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}
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; CHECK-LABEL: test_modulo_analysis_in_loop
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; CHECK: NoAlias: i32** %x, i32** %y
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define void @test_modulo_analysis_in_loop() {
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%h = alloca [1 x [2 x i32*]], align 16
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br label %for.loop
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for.loop:
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%i = phi i32 [ 0, %0 ], [ %i.plus1, %for.loop ]
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%i.promoted = sext i32 %i to i64
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%x = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 %i.promoted, i64 0
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%y = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 0, i64 1
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%i.plus1 = add nsw i32 %i, 1
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%cmp = icmp slt i32 %i.plus1, 2
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br i1 %cmp, label %for.loop, label %for.loop.exit
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for.loop.exit:
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ret void
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}
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; CHECK-LABEL: test_modulo_analysis_with_global
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; CHECK: PartialAlias: i32** %x, i32** %y
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define void @test_modulo_analysis_with_global() {
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%h = alloca [1 x [2 x i32*]], align 16
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%b = load i32, i32* @b, align 4
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%b.promoted = sext i32 %b to i64
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br label %for.loop
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for.loop:
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%i = phi i32 [ 0, %0 ], [ %i.plus1, %for.loop ]
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%i.promoted = sext i32 %i to i64
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%x = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 %i.promoted, i64 %b.promoted
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%y = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 0, i64 1
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%i.plus1 = add nsw i32 %i, 1
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%cmp = icmp slt i32 %i.plus1, 2
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br i1 %cmp, label %for.loop, label %for.loop.exit
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for.loop.exit:
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ret void
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}
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; CHECK-LABEL: test_const_eval
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; CHECK: NoAlias: i8* %a, i8* %b
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define void @test_const_eval(i8* %ptr, i64 %offset) {
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%a = getelementptr inbounds i8, i8* %ptr, i64 %offset
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%a.dup = getelementptr inbounds i8, i8* %ptr, i64 %offset
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%three = zext i32 3 to i64
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%b = getelementptr inbounds i8, i8* %a.dup, i64 %three
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ret void
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}
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; CHECK-LABEL: test_const_eval_scaled
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; CHECK: MustAlias: i8* %a, i8* %b
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define void @test_const_eval_scaled(i8* %ptr) {
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%three = zext i32 3 to i64
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%six = mul i64 %three, 2
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%a = getelementptr inbounds i8, i8* %ptr, i64 %six
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%b = getelementptr inbounds i8, i8* %ptr, i64 6
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ret void
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}
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; Function Attrs: nounwind
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declare noalias i8* @malloc(i64)
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