[llvm] r218944 - [BasicAA] Revert r218714 - Make better use of zext and sign information.
Lang Hames
lhames at gmail.com
Thu Oct 2 18:33:47 PDT 2014
Author: lhames
Date: Thu Oct 2 20:33:47 2014
New Revision: 218944
URL: http://llvm.org/viewvc/llvm-project?rev=218944&view=rev
Log:
[BasicAA] Revert r218714 - Make better use of zext and sign information.
This patch broke 447.dealII on Darwin. I'm currently working on a reduced
test-case, but reverting for now to keep the bots happy.
<rdar://problem/18530107>
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=218944&r1=218943&r2=218944&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp Thu Oct 2 20:33:47 2014
@@ -254,10 +254,7 @@ static Value *GetLinearExpression(Value
Value *Result = GetLinearExpression(CastOp, Scale, Offset, Extension,
DL, Depth+1, AT, 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;
}
@@ -1058,26 +1055,8 @@ BasicAliasAnalysis::aliasGEP(const GEPOp
// 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) {
- const Value *V = GEP1VariableIndices[i].V;
+ for (unsigned i = 0, e = GEP1VariableIndices.size(); i != e; ++i)
Modulo |= (uint64_t)GEP1VariableIndices[i].Scale;
-
- // If the variable's been zero-extended or begins with a zero then
- // we know it's positive. regardless of whether the value is signed
- // or unsigned.
- bool SignKnownZero, SignKnownOne;
- ComputeSignBit(
- const_cast<Value *>(V),
- SignKnownZero, SignKnownOne,
- DL, 0, AT, nullptr, DT);
- bool IsZExt = GEP1VariableIndices[i].Extension == EK_ZeroExt;
- AllPositive &= IsZExt || SignKnownZero;
-
- // If the Value is currently positive but could change in a cycle,
- // then we can't guarantee it'll always br positive.
- AllPositive &= isValueEqualInPotentialCycles(V, V);
- }
Modulo = Modulo ^ (Modulo & (Modulo - 1));
// We can compute the difference between the two addresses
@@ -1087,12 +1066,6 @@ BasicAliasAnalysis::aliasGEP(const GEPOp
if (V1Size != UnknownSize && V2Size != 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=218944&r1=218943&r2=218944&view=diff
==============================================================================
--- llvm/trunk/test/Analysis/BasicAA/phi-aa.ll (original)
+++ llvm/trunk/test/Analysis/BasicAA/phi-aa.ll Thu Oct 2 20:33:47 2014
@@ -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=218943&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/BasicAA/zext.ll (original)
+++ llvm/trunk/test/Analysis/BasicAA/zext.ll (removed)
@@ -1,65 +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* %1, i64 8
- %2 = getelementptr inbounds i8* %1, i64 16
- %3 = zext i32 3 to i64
- %b = getelementptr inbounds 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* %1, i64 8
- %2 = getelementptr inbounds i8* %1, i64 16
- %3 = lshr i64 %i, 2
- %b = getelementptr inbounds i8* %2, i64 %3
- ret void
-}
-
-; CHECK-LABEL: test_with_a_loop
-; CHECK: NoAlias: i8* %a, i8* %b
-
-define void @test_with_a_loop() {
- %1 = tail call i8* @malloc(i64 120)
- %a = getelementptr inbounds i8* %1, i64 8
- %2 = getelementptr inbounds i8* %1, i64 16
- br label %for.loop
-
-for.loop:
- %i = phi i32 [ 0, %0 ], [ %i.next, %for.loop ]
- %3 = zext i32 %i to i64
- %b = getelementptr inbounds i8* %2, i64 %3
- %i.next = add nuw nsw i32 %i, 1
- %4 = icmp eq i32 %i.next, 10
- br i1 %4, 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* %1, i64 %p.64
- %p.minus1 = add i32 %p, -1
- %p.minus1.64 = zext i32 %p.minus1 to i64
- %b.i8 = getelementptr inbounds i8* %1, i64 %p.minus1.64
- %b.i64 = bitcast i8* %b.i8 to i64*
- ret void
-}
-
-; Function Attrs: nounwind
-declare noalias i8* @malloc(i64)
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