Revert commit 131781, to see if it fixes the x86-64 dragonegg buildbot.

Original log message:
When BasicAA can determine that two pointers have the same base but
differ by a dynamic offset, return PartialAlias instead of MayAlias.
See the comment in the code for details. This fixes PR9971.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131809 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 2 insertions, 143 deletions

diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp
index f506608..f1bb8a3 100644
--- a/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/lib/Analysis/BasicAliasAnalysis.cpp
@@ -940,17 +940,7 @@ BasicAliasAnalysis::aliasGEP(const GEPOperator *GEP1, uint64_t V1Size,
       return NoAlias;
   }
   
-  // Statically, we can see that the base objects are the same, but the
-  // pointers have dynamic offsets which we can't resolve. And none of our
-  // little tricks above worked.
-  //
-  // TODO: Returning PartialAlias instead of MayAlias is a mild hack; the
-  // practical effect of this is protecting TBAA in the case of dynamic
-  // indices into arrays of unions. An alternative way to solve this would
-  // be to have clang emit extra metadata for unions and/or union accesses.
-  // A union-specific solution wouldn't handle the problem for malloc'd
-  // memory however.
-  return PartialAlias;
+  return MayAlias;
 }
 
 /// aliasSelect - Provide a bunch of ad-hoc rules to disambiguate a Select
diff --git a/test/Analysis/BasicAA/2010-09-15-GEP-SignedArithmetic.ll b/test/Analysis/BasicAA/2010-09-15-GEP-SignedArithmetic.ll
index 7b5584e..2b0cd78 100644
--- a/test/Analysis/BasicAA/2010-09-15-GEP-SignedArithmetic.ll
+++ b/test/Analysis/BasicAA/2010-09-15-GEP-SignedArithmetic.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -basicaa -aa-eval -print-all-alias-modref-info -disable-output |& grep {1 partial alias}
+; RUN: opt < %s -basicaa -aa-eval -print-all-alias-modref-info -disable-output |& grep {1 may alias}
 ; PR7959
 
 target datalayout = "e-p:32:32:32"
diff --git a/test/Analysis/TypeBasedAliasAnalysis/dynamic-indices.ll b/test/Analysis/TypeBasedAliasAnalysis/dynamic-indices.ll
deleted file mode 100644
index 52e394b..0000000
--- a/test/Analysis/TypeBasedAliasAnalysis/dynamic-indices.ll
+++ /dev/null
@@ -1,131 +0,0 @@
-; RUN: opt -tbaa -basicaa -gvn -S < %s | FileCheck %s
-; PR9971
-
-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"
-
-%struct.X = type { i32, float }
-%union.vector_t = type { [2 x i64] }
-
-; Don't delete the load after the loop, because it loads values stored
-; inside the loop.
-
-; CHECK: define void @vrlh(
-
-; CHECK: for.end:
-; CHECK:   %arrayidx31 = getelementptr inbounds %union.vector_t* %t, i64 0, i32 0, i64 1
-; CHECK:   %tmp32 = load i64* %arrayidx31, align 8, !tbaa !3
-
-define void @vrlh(%union.vector_t* %va, %union.vector_t* %vb, %union.vector_t* %vd) nounwind {
-entry:
-  %t = alloca %union.vector_t, align 8
-  br label %for.body
-
-for.body:                                         ; preds = %entry, %for.body
-  %i.01 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
-  %sub = sub nsw i32 7, %i.01
-  %idxprom = sext i32 %sub to i64
-  %half = bitcast %union.vector_t* %vb to [8 x i16]*
-  %arrayidx = getelementptr inbounds [8 x i16]* %half, i64 0, i64 %idxprom
-  %tmp4 = load i16* %arrayidx, align 2, !tbaa !0
-  %conv = zext i16 %tmp4 to i32
-  %and = and i32 %conv, 15
-  %sub6 = sub nsw i32 7, %i.01
-  %idxprom7 = sext i32 %sub6 to i64
-  %half9 = bitcast %union.vector_t* %va to [8 x i16]*
-  %arrayidx10 = getelementptr inbounds [8 x i16]* %half9, i64 0, i64 %idxprom7
-  %tmp11 = load i16* %arrayidx10, align 2, !tbaa !0
-  %conv12 = zext i16 %tmp11 to i32
-  %shl = shl i32 %conv12, %and
-  %sub15 = sub nsw i32 7, %i.01
-  %idxprom16 = sext i32 %sub15 to i64
-  %half18 = bitcast %union.vector_t* %va to [8 x i16]*
-  %arrayidx19 = getelementptr inbounds [8 x i16]* %half18, i64 0, i64 %idxprom16
-  %tmp20 = load i16* %arrayidx19, align 2, !tbaa !0
-  %conv21 = zext i16 %tmp20 to i32
-  %sub23 = sub nsw i32 16, %and
-  %shr = lshr i32 %conv21, %sub23
-  %or = or i32 %shl, %shr
-  %conv24 = trunc i32 %or to i16
-  %sub26 = sub nsw i32 7, %i.01
-  %idxprom27 = sext i32 %sub26 to i64
-  %half28 = bitcast %union.vector_t* %t to [8 x i16]*
-  %arrayidx29 = getelementptr inbounds [8 x i16]* %half28, i64 0, i64 %idxprom27
-  store i16 %conv24, i16* %arrayidx29, align 2, !tbaa !0
-  %inc = add nsw i32 %i.01, 1
-  %cmp = icmp slt i32 %inc, 8
-  br i1 %cmp, label %for.body, label %for.end
-
-for.end:                                          ; preds = %for.body
-  %arrayidx31 = getelementptr inbounds %union.vector_t* %t, i64 0, i32 0, i64 1
-  %tmp32 = load i64* %arrayidx31, align 8, !tbaa !3
-  %arrayidx35 = getelementptr inbounds %union.vector_t* %vd, i64 0, i32 0, i64 1
-  store i64 %tmp32, i64* %arrayidx35, align 8, !tbaa !3
-  %arrayidx37 = getelementptr inbounds %union.vector_t* %t, i64 0, i32 0, i64 0
-  %tmp38 = load i64* %arrayidx37, align 8, !tbaa !3
-  %arrayidx41 = getelementptr inbounds %union.vector_t* %vd, i64 0, i32 0, i64 0
-  store i64 %tmp38, i64* %arrayidx41, align 8, !tbaa !3
-  ret void
-}
-
-; Do delete the load after the loop.
-
-; CHECK: define i32 @test0(
-
-; CHECK:   ret i32 0
-
-define i32 @test0(%struct.X* %a) nounwind {
-entry:
-  %i = getelementptr inbounds %struct.X* %a, i64 0, i32 0
-  store i32 0, i32* %i, align 4, !tbaa !4
-  br label %for.body
-
-for.body:                                         ; preds = %entry, %for.body
-  %i2.01 = phi i64 [ 0, %entry ], [ %inc, %for.body ]
-  %f = getelementptr inbounds %struct.X* %a, i64 %i2.01, i32 1
-  %tmp6 = load float* %f, align 4, !tbaa !5
-  %mul = fmul float %tmp6, 0x40019999A0000000
-  store float %mul, float* %f, align 4, !tbaa !5
-  %inc = add nsw i64 %i2.01, 1
-  %cmp = icmp slt i64 %inc, 10000
-  br i1 %cmp, label %for.body, label %for.end
-
-for.end:                                          ; preds = %for.body
-  %i9 = getelementptr inbounds %struct.X* %a, i64 0, i32 0
-  %tmp10 = load i32* %i9, align 4, !tbaa !4
-  ret i32 %tmp10
-}
-
-; Do delete the load after the loop.
-
-; CHECK: define float @test1(
-
-; CHECK:   ret float 0x3FD3333340000000
-
-define float @test1(%struct.X* %a) nounwind {
-entry:
-  %f = getelementptr inbounds %struct.X* %a, i64 0, i32 1
-  store float 0x3FD3333340000000, float* %f, align 4, !tbaa !5
-  br label %for.body
-
-for.body:                                         ; preds = %entry, %for.body
-  %i.01 = phi i64 [ 0, %entry ], [ %inc, %for.body ]
-  %i5 = getelementptr inbounds %struct.X* %a, i64 %i.01, i32 0
-  %tmp6 = load i32* %i5, align 4, !tbaa !4
-  %mul = mul nsw i32 %tmp6, 3
-  store i32 %mul, i32* %i5, align 4, !tbaa !4
-  %inc = add nsw i64 %i.01, 1
-  %cmp = icmp slt i64 %inc, 10000
-  br i1 %cmp, label %for.body, label %for.end
-
-for.end:                                          ; preds = %for.body
-  %f9 = getelementptr inbounds %struct.X* %a, i64 0, i32 1
-  %tmp10 = load float* %f9, align 4, !tbaa !5
-  ret float %tmp10
-}
-
-!0 = metadata !{metadata !"short", metadata !1}
-!1 = metadata !{metadata !"omnipotent char", metadata !2}
-!2 = metadata !{metadata !"Simple C/C++ TBAA", null}
-!3 = metadata !{metadata !"long long", metadata !1}
-!4 = metadata !{metadata !"int", metadata !1}
-!5 = metadata !{metadata !"float", metadata !1}