PR9634: Don't unconditionally tell the AliasSetTracker that the PreheaderLoad

is equivalent to any other relevant value; it isn't true in general.
If it is equivalent, the LoopPromoter will tell the AST the equivalence.
Also, delete the PreheaderLoad if it is unused.

Chris, since you were the last one to make major changes here, can you check
that this is sane?



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129049 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 40 insertions, 1 deletions

diff --git a/test/Transforms/LICM/2007-10-01-PromoteSafeValue.ll b/test/Transforms/LICM/2007-10-01-PromoteSafeValue.ll
index 59f1dcb..e3d0d02 100644
--- a/test/Transforms/LICM/2007-10-01-PromoteSafeValue.ll
+++ b/test/Transforms/LICM/2007-10-01-PromoteSafeValue.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -licm -S | grep promoted
+; RUN: opt < %s -licm -S | FileCheck %s
 ; Promote value if at least one use is safe
 
 
@@ -15,6 +15,8 @@ cond.true:              ; preds = %loop.head
         store i32 40, i32* %p
         br label %loop.head
 
+; CHECK: exit:
+; CHECK: store i32 20, i32* %p
 exit:           ; preds = %loop.head
         ret i32 0
 }
diff --git a/test/Transforms/LICM/2011-04-06-PromoteResultOfPromotion.ll b/test/Transforms/LICM/2011-04-06-PromoteResultOfPromotion.ll
new file mode 100644
index 0000000..86c2679
--- /dev/null
+++ b/test/Transforms/LICM/2011-04-06-PromoteResultOfPromotion.ll
@@ -0,0 +1,37 @@
+; RUN: opt < %s -tbaa -licm -S | FileCheck %s
+; PR9634
+
+@g_58 = common global i32 0, align 4
+@g_116 = common global i32* null, align 8
+
+define void @f() nounwind {
+
+; CHECK: entry:
+; CHECK: alloca [9 x i16]
+; CHECK: load i32* @g_58
+; CHECK: br label %for.body
+
+entry:
+  %l_87.i = alloca [9 x i16], align 16
+  br label %for.body
+
+for.body:                                         ; preds = %entry, %for.inc
+  %inc12 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+  store i32* @g_58, i32** @g_116, align 8, !tbaa !0
+  %tmp2 = load i32** @g_116, align 8, !tbaa !0
+  %tmp3 = load i32* %tmp2, !tbaa !4
+  %or = or i32 %tmp3, 10
+  store i32 %or, i32* %tmp2, !tbaa !4
+  %inc = add nsw i32 %inc12, 1
+  %cmp = icmp slt i32 %inc, 4
+  br i1 %cmp, label %for.body, label %for.end
+
+for.end:                                          ; preds = %for.inc
+  ret void
+}
+
+!0 = metadata !{metadata !"any pointer", metadata !1}
+!1 = metadata !{metadata !"omnipotent char", metadata !2}
+!2 = metadata !{metadata !"Simple C/C++ TBAA", null}
+!3 = metadata !{metadata !"short", metadata !1}
+!4 = metadata !{metadata !"int", metadata !1}