Change the other half of aliasGEP (which handles GEP differencing) to use DecomposeGEPExpression. This dramatically simplifies and shrinks the code by eliminating the horrible CheckGEPInstructions method, fixes a miscompilation (@test3) and makes the code more aggressive. In particular, we now handle the @test4 case, which is reduced from the SmallPtrSet constructor. Missing this caused us to emit a variable length memset instead of a fixed size one.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89922 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 59 insertions, 2 deletions

diff --git a/test/Analysis/BasicAA/2008-12-09-GEP-IndicesAlias.ll b/test/Analysis/BasicAA/2008-12-09-GEP-IndicesAlias.ll
index aaf9061..e8f8a8e 100644
--- a/test/Analysis/BasicAA/2008-12-09-GEP-IndicesAlias.ll
+++ b/test/Analysis/BasicAA/2008-12-09-GEP-IndicesAlias.ll
@@ -1,7 +1,9 @@
-; RUN: opt < %s -aa-eval -print-all-alias-modref-info -disable-output |& grep {MustAlias:.*%R,.*%r}
+; RUN: opt < %s -gvn -instcombine -S |& FileCheck %s
 ; Make sure that basicaa thinks R and r are must aliases.
 
-define i32 @test(i8 * %P) {
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+
+define i32 @test1(i8 * %P) {
 entry:
 	%Q = bitcast i8* %P to {i32, i32}*
 	%R = getelementptr {i32, i32}* %Q, i32 0, i32 1
@@ -13,4 +15,59 @@ entry:
 
 	%t = sub i32 %S, %s
 	ret i32 %t
+; CHECK: @test1
+; CHECK: ret i32 0
+}
+
+define i32 @test2(i8 * %P) {
+entry:
+	%Q = bitcast i8* %P to {i32, i32, i32}*
+	%R = getelementptr {i32, i32, i32}* %Q, i32 0, i32 1
+	%S = load i32* %R
+
+	%r = getelementptr {i32, i32, i32}* %Q, i32 0, i32 2
+  store i32 42, i32* %r
+
+	%s = load i32* %R
+
+	%t = sub i32 %S, %s
+	ret i32 %t
+; CHECK: @test2
+; CHECK: ret i32 0
+}
+
+
+; This was a miscompilation.
+define i32 @test3({float, {i32, i32, i32}}* %P) {
+entry:
+  %P2 = getelementptr {float, {i32, i32, i32}}* %P, i32 0, i32 1
+	%R = getelementptr {i32, i32, i32}* %P2, i32 0, i32 1
+	%S = load i32* %R
+
+	%r = getelementptr {i32, i32, i32}* %P2, i32 0, i32 2
+  store i32 42, i32* %r
+
+	%s = load i32* %R
+
+	%t = sub i32 %S, %s
+	ret i32 %t
+; CHECK: @test3
+; CHECK: ret i32 0
+}
+
+
+;; This is reduced from the SmallPtrSet constructor.
+%SmallPtrSetImpl = type { i8**, i32, i32, i32, [1 x i8*] }
+%SmallPtrSet64 = type { %SmallPtrSetImpl, [64 x i8*] }
+
+define i32 @test4(%SmallPtrSet64* %P) {
+entry:
+  %tmp2 = getelementptr inbounds %SmallPtrSet64* %P, i64 0, i32 0, i32 1
+  store i32 64, i32* %tmp2, align 8
+  %tmp3 = getelementptr inbounds %SmallPtrSet64* %P, i64 0, i32 0, i32 4, i64 64
+  store i8* null, i8** %tmp3, align 8
+  %tmp4 = load i32* %tmp2, align 8
+	ret i32 %tmp4
+; CHECK: @test4
+; CHECK: ret i32 64
 }