From: Lang Hames Date: Fri, 3 Oct 2014 01:33:47 +0000 (+0000) Subject: [BasicAA] Revert r218714 - Make better use of zext and sign information. X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=commitdiff_plain;h=07c5f89fa10729d549f5bdfa5b4b3ff64d42a703 [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. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218944 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp index f4052b9dbab..9cfd02c0218 100644 --- a/lib/Analysis/BasicAliasAnalysis.cpp +++ b/lib/Analysis/BasicAliasAnalysis.cpp @@ -254,10 +254,7 @@ static Value *GetLinearExpression(Value *V, APInt &Scale, APInt &Offset, 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 GEPOperator *GEP1, uint64_t V1Size, // 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(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 GEPOperator *GEP1, uint64_t V1Size, 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 diff --git a/test/Analysis/BasicAA/phi-aa.ll b/test/Analysis/BasicAA/phi-aa.ll index c1100f1d36f..74279e1c4c9 100644 --- a/test/Analysis/BasicAA/phi-aa.ll +++ b/test/Analysis/BasicAA/phi-aa.ll @@ -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: diff --git a/test/Analysis/BasicAA/zext.ll b/test/Analysis/BasicAA/zext.ll deleted file mode 100644 index 07912d5a4ea..00000000000 --- a/test/Analysis/BasicAA/zext.ll +++ /dev/null @@ -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)