[llvm] r245394 - [BasicAA] Revert r221876 because it can produce incorrect aliasing
Quentin Colombet via llvm-commits
llvm-commits at lists.llvm.org
Tue Aug 18 17:07:20 PDT 2015
Author: qcolombet
Date: Tue Aug 18 19:07:20 2015
New Revision: 245394
URL: http://llvm.org/viewvc/llvm-project?rev=245394&view=rev
Log:
[BasicAA] Revert r221876 because it can produce incorrect aliasing
information: see PR24468.
Removed:
llvm/trunk/test/Analysis/BasicAA/zext.ll
Modified:
llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
llvm/trunk/test/Analysis/BasicAA/phi-aa.ll
Modified: llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp?rev=245394&r1=245393&r2=245394&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp Tue Aug 18 19:07:20 2015
@@ -190,14 +190,6 @@ static bool isObjectSize(const Value *V,
return V;
}
- if (ConstantInt *Const = dyn_cast<ConstantInt>(V)) {
- // if it's a constant, just convert it to an offset
- // and remove the variable.
- Offset += Const->getValue();
- assert(Scale == 0 && "Constant values don't have a scale");
- return V;
- }
-
if (BinaryOperator *BOp = dyn_cast<BinaryOperator>(V)) {
if (ConstantInt *RHSC = dyn_cast<ConstantInt>(BOp->getOperand(1))) {
switch (BOp->getOpcode()) {
@@ -246,10 +238,7 @@ static bool isObjectSize(const Value *V,
Value *Result = GetLinearExpression(CastOp, Scale, Offset, Extension, DL,
Depth + 1, AC, DT);
Scale = Scale.zext(OldWidth);
-
- // We have to sign-extend even if Extension == EK_ZeroExt as we can't
- // decompose a sign extension (i.e. zext(x - 1) != zext(x) - zext(-1)).
- Offset = Offset.sext(OldWidth);
+ Offset = Offset.zext(OldWidth);
return Result;
}
@@ -959,42 +948,12 @@ AliasResult BasicAliasAnalysis::aliasGEP
}
}
+ // Try to distinguish something like &A[i][1] against &A[42][0].
+ // Grab the least significant bit set in any of the scales.
if (!GEP1VariableIndices.empty()) {
uint64_t Modulo = 0;
- bool AllPositive = true;
- for (unsigned i = 0, e = GEP1VariableIndices.size(); i != e; ++i) {
-
- // Try to distinguish something like &A[i][1] against &A[42][0].
- // Grab the least significant bit set in any of the scales. We
- // don't need std::abs here (even if the scale's negative) as we'll
- // be ^'ing Modulo with itself later.
+ for (unsigned i = 0, e = GEP1VariableIndices.size(); i != e; ++i)
Modulo |= (uint64_t)GEP1VariableIndices[i].Scale;
-
- if (AllPositive) {
- // If the Value could change between cycles, then any reasoning about
- // the Value this cycle may not hold in the next cycle. We'll just
- // give up if we can't determine conditions that hold for every cycle:
- const Value *V = GEP1VariableIndices[i].V;
-
- bool SignKnownZero, SignKnownOne;
- ComputeSignBit(const_cast<Value *>(V), SignKnownZero, SignKnownOne, *DL,
- 0, AC1, nullptr, DT);
-
- // Zero-extension widens the variable, and so forces the sign
- // bit to zero.
- bool IsZExt = GEP1VariableIndices[i].Extension == EK_ZeroExt;
- SignKnownZero |= IsZExt;
- SignKnownOne &= !IsZExt;
-
- // If the variable begins with a zero then we know it's
- // positive, regardless of whether the value is signed or
- // unsigned.
- int64_t Scale = GEP1VariableIndices[i].Scale;
- AllPositive =
- (SignKnownZero && Scale >= 0) || (SignKnownOne && Scale < 0);
- }
- }
-
Modulo = Modulo ^ (Modulo & (Modulo - 1));
// We can compute the difference between the two addresses
@@ -1005,12 +964,6 @@ AliasResult BasicAliasAnalysis::aliasGEP
V2Size != MemoryLocation::UnknownSize && ModOffset >= V2Size &&
V1Size <= Modulo - ModOffset)
return NoAlias;
-
- // If we know all the variables are positive, then GEP1 >= GEP1BasePtr.
- // If GEP1BasePtr > V2 (GEP1BaseOffset > 0) then we know the pointers
- // don't alias if V2Size can fit in the gap between V2 and GEP1BasePtr.
- if (AllPositive && GEP1BaseOffset > 0 && V2Size <= (uint64_t)GEP1BaseOffset)
- return NoAlias;
}
// Statically, we can see that the base objects are the same, but the
Modified: llvm/trunk/test/Analysis/BasicAA/phi-aa.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/BasicAA/phi-aa.ll?rev=245394&r1=245393&r2=245394&view=diff
==============================================================================
--- llvm/trunk/test/Analysis/BasicAA/phi-aa.ll (original)
+++ llvm/trunk/test/Analysis/BasicAA/phi-aa.ll Tue Aug 18 19:07:20 2015
@@ -39,7 +39,6 @@ return:
; CHECK-LABEL: pr18068
; CHECK: MayAlias: i32* %0, i32* %arrayidx5
-; CHECK: NoAlias: i32* %arrayidx13, i32* %arrayidx5
define i32 @pr18068(i32* %jj7, i32* %j) {
entry:
Removed: llvm/trunk/test/Analysis/BasicAA/zext.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/BasicAA/zext.ll?rev=245393&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/BasicAA/zext.ll (original)
+++ llvm/trunk/test/Analysis/BasicAA/zext.ll (removed)
@@ -1,209 +0,0 @@
-; RUN: opt < %s -basicaa -aa-eval -print-all-alias-modref-info -disable-output 2>&1 | FileCheck %s
-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"
-target triple = "x86_64-unknown-linux-gnu"
-
-; CHECK-LABEL: test_with_zext
-; CHECK: NoAlias: i8* %a, i8* %b
-
-define void @test_with_zext() {
- %1 = tail call i8* @malloc(i64 120)
- %a = getelementptr inbounds i8, i8* %1, i64 8
- %2 = getelementptr inbounds i8, i8* %1, i64 16
- %3 = zext i32 3 to i64
- %b = getelementptr inbounds i8, i8* %2, i64 %3
- ret void
-}
-
-; CHECK-LABEL: test_with_lshr
-; CHECK: NoAlias: i8* %a, i8* %b
-
-define void @test_with_lshr(i64 %i) {
- %1 = tail call i8* @malloc(i64 120)
- %a = getelementptr inbounds i8, i8* %1, i64 8
- %2 = getelementptr inbounds i8, i8* %1, i64 16
- %3 = lshr i64 %i, 2
- %b = getelementptr inbounds i8, i8* %2, i64 %3
- ret void
-}
-
-; CHECK-LABEL: test_with_a_loop
-; CHECK: NoAlias: i8* %a, i8* %b
-
-define void @test_with_a_loop(i8* %mem) {
- br label %for.loop
-
-for.loop:
- %i = phi i32 [ 0, %0 ], [ %i.plus1, %for.loop ]
- %a = getelementptr inbounds i8, i8* %mem, i64 8
- %a.plus1 = getelementptr inbounds i8, i8* %mem, i64 16
- %i.64 = zext i32 %i to i64
- %b = getelementptr inbounds i8, i8* %a.plus1, i64 %i.64
- %i.plus1 = add nuw nsw i32 %i, 1
- %cmp = icmp eq i32 %i.plus1, 10
- br i1 %cmp, label %for.loop.exit, label %for.loop
-
-for.loop.exit:
- ret void
-}
-
-; CHECK-LABEL: test_with_varying_base_pointer_in_loop
-; CHECK: NoAlias: i8* %a, i8* %b
-
-define void @test_with_varying_base_pointer_in_loop(i8* %mem.orig) {
- br label %for.loop
-
-for.loop:
- %mem = phi i8* [ %mem.orig, %0 ], [ %mem.plus1, %for.loop ]
- %i = phi i32 [ 0, %0 ], [ %i.plus1, %for.loop ]
- %a = getelementptr inbounds i8, i8* %mem, i64 8
- %a.plus1 = getelementptr inbounds i8, i8* %mem, i64 16
- %i.64 = zext i32 %i to i64
- %b = getelementptr inbounds i8, i8* %a.plus1, i64 %i.64
- %i.plus1 = add nuw nsw i32 %i, 1
- %mem.plus1 = getelementptr inbounds i8, i8* %mem, i64 8
- %cmp = icmp eq i32 %i.plus1, 10
- br i1 %cmp, label %for.loop.exit, label %for.loop
-
-for.loop.exit:
- ret void
-}
-
-; CHECK-LABEL: test_sign_extension
-; CHECK: PartialAlias: i64* %b.i64, i8* %a
-
-define void @test_sign_extension(i32 %p) {
- %1 = tail call i8* @malloc(i64 120)
- %p.64 = zext i32 %p to i64
- %a = getelementptr inbounds i8, i8* %1, i64 %p.64
- %p.minus1 = add i32 %p, -1
- %p.minus1.64 = zext i32 %p.minus1 to i64
- %b.i8 = getelementptr inbounds i8, i8* %1, i64 %p.minus1.64
- %b.i64 = bitcast i8* %b.i8 to i64*
- ret void
-}
-
-; CHECK-LABEL: test_fe_tools
-; CHECK: PartialAlias: i32* %a, i32* %b
-
-define void @test_fe_tools([8 x i32]* %values) {
- br label %reorder
-
-for.loop:
- %i = phi i32 [ 0, %reorder ], [ %i.next, %for.loop ]
- %idxprom = zext i32 %i to i64
- %b = getelementptr inbounds [8 x i32], [8 x i32]* %values, i64 0, i64 %idxprom
- %i.next = add nuw nsw i32 %i, 1
- %1 = icmp eq i32 %i.next, 10
- br i1 %1, label %for.loop.exit, label %for.loop
-
-reorder:
- %a = getelementptr inbounds [8 x i32], [8 x i32]* %values, i64 0, i64 1
- br label %for.loop
-
-for.loop.exit:
- ret void
-}
-
- at b = global i32 0, align 4
- at d = global i32 0, align 4
-
-; CHECK-LABEL: test_spec2006
-; CHECK: PartialAlias: i32** %x, i32** %y
-
-define void @test_spec2006() {
- %h = alloca [1 x [2 x i32*]], align 16
- %d.val = load i32, i32* @d, align 4
- %d.promoted = sext i32 %d.val to i64
- %1 = icmp slt i32 %d.val, 2
- br i1 %1, label %.lr.ph, label %3
-
-.lr.ph: ; preds = %0
- br label %2
-
-; <label>:2 ; preds = %.lr.ph, %2
- %i = phi i32 [ %d.val, %.lr.ph ], [ %i.plus1, %2 ]
- %i.promoted = sext i32 %i to i64
- %x = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 %d.promoted, i64 %i.promoted
- %i.plus1 = add nsw i32 %i, 1
- %cmp = icmp slt i32 %i.plus1, 2
- br i1 %cmp, label %2, label %3
-
-; <label>:3 ; preds = %._crit_edge, %0
- %y = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 0, i64 1
- ret void
-}
-
-; CHECK-LABEL: test_modulo_analysis_easy_case
-; CHECK: NoAlias: i32** %x, i32** %y
-
-define void @test_modulo_analysis_easy_case(i64 %i) {
- %h = alloca [1 x [2 x i32*]], align 16
- %x = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 %i, i64 0
- %y = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 0, i64 1
- ret void
-}
-
-; CHECK-LABEL: test_modulo_analysis_in_loop
-; CHECK: NoAlias: i32** %x, i32** %y
-
-define void @test_modulo_analysis_in_loop() {
- %h = alloca [1 x [2 x i32*]], align 16
- br label %for.loop
-
-for.loop:
- %i = phi i32 [ 0, %0 ], [ %i.plus1, %for.loop ]
- %i.promoted = sext i32 %i to i64
- %x = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 %i.promoted, i64 0
- %y = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 0, i64 1
- %i.plus1 = add nsw i32 %i, 1
- %cmp = icmp slt i32 %i.plus1, 2
- br i1 %cmp, label %for.loop, label %for.loop.exit
-
-for.loop.exit:
- ret void
-}
-
-; CHECK-LABEL: test_modulo_analysis_with_global
-; CHECK: PartialAlias: i32** %x, i32** %y
-
-define void @test_modulo_analysis_with_global() {
- %h = alloca [1 x [2 x i32*]], align 16
- %b = load i32, i32* @b, align 4
- %b.promoted = sext i32 %b to i64
- br label %for.loop
-
-for.loop:
- %i = phi i32 [ 0, %0 ], [ %i.plus1, %for.loop ]
- %i.promoted = sext i32 %i to i64
- %x = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 %i.promoted, i64 %b.promoted
- %y = getelementptr inbounds [1 x [2 x i32*]], [1 x [2 x i32*]]* %h, i64 0, i64 0, i64 1
- %i.plus1 = add nsw i32 %i, 1
- %cmp = icmp slt i32 %i.plus1, 2
- br i1 %cmp, label %for.loop, label %for.loop.exit
-
-for.loop.exit:
- ret void
-}
-
-; CHECK-LABEL: test_const_eval
-; CHECK: NoAlias: i8* %a, i8* %b
-define void @test_const_eval(i8* %ptr, i64 %offset) {
- %a = getelementptr inbounds i8, i8* %ptr, i64 %offset
- %a.dup = getelementptr inbounds i8, i8* %ptr, i64 %offset
- %three = zext i32 3 to i64
- %b = getelementptr inbounds i8, i8* %a.dup, i64 %three
- ret void
-}
-
-; CHECK-LABEL: test_const_eval_scaled
-; CHECK: MustAlias: i8* %a, i8* %b
-define void @test_const_eval_scaled(i8* %ptr) {
- %three = zext i32 3 to i64
- %six = mul i64 %three, 2
- %a = getelementptr inbounds i8, i8* %ptr, i64 %six
- %b = getelementptr inbounds i8, i8* %ptr, i64 6
- ret void
-}
-
-; Function Attrs: nounwind
-declare noalias i8* @malloc(i64)
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