When merging MustAlias and PartialAlias, chose PartialAlias instead

of conservatively choosing MayAlias.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132579 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 39 insertions, 0 deletions

diff --git a/test/Analysis/BasicAA/must-and-partial.ll b/test/Analysis/BasicAA/must-and-partial.ll
new file mode 100644
index 0000000000..93b6184f4f
--- /dev/null
+++ b/test/Analysis/BasicAA/must-and-partial.ll
@@ -0,0 +1,39 @@
+; RUN: opt < %s -basicaa -aa-eval -print-all-alias-modref-info |& FileCheck %s
+
+; When merging MustAlias and PartialAlias, merge to PartialAlias
+; instead of MayAlias.
+
+
+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"
+
+; CHECK: PartialAlias:  i16* %bigbase0, i8* %phi
+define i8 @test0(i8* %base, i1 %x) {
+entry:
+  %baseplusone = getelementptr i8* %base, i64 1
+  br i1 %x, label %red, label %green
+red:
+  br label %green
+green:
+  %phi = phi i8* [ %baseplusone, %red ], [ %base, %entry ]
+  store i8 0, i8* %phi
+
+  %bigbase0 = bitcast i8* %base to i16*
+  store i16 -1, i16* %bigbase0
+
+  %loaded = load i8* %phi
+  ret i8 %loaded
+}
+
+; CHECK: PartialAlias:  i16* %bigbase1, i8* %sel
+define i8 @test1(i8* %base, i1 %x) {
+entry:
+  %baseplusone = getelementptr i8* %base, i64 1
+  %sel = select i1 %x, i8* %baseplusone, i8* %base
+  store i8 0, i8* %sel
+
+  %bigbase1 = bitcast i8* %base to i16*
+  store i16 -1, i16* %bigbase1
+
+  %loaded = load i8* %sel
+  ret i8 %loaded
+}