fix a miscompilation of tramp3d-v4: when forming a memcpy, we have to make
sure that the loop we're promoting into a memcpy doesn't mutate the input
of the memcpy. Before we were just checking that the dest of the memcpy
wasn't mod/ref'd by the loop.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122712 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Transforms/LoopIdiom/basic.ll b/test/Transforms/LoopIdiom/basic.ll
index e8e0f38..f3b55d7 100644
--- a/test/Transforms/LoopIdiom/basic.ll
+++ b/test/Transforms/LoopIdiom/basic.ll
@@ -207,3 +207,36 @@
; CHECK: store i64 0, i64* %PI
}
+declare i8* @external(i8*)
+
+;; This cannot be transformed into a memcpy, because the read-from location is
+;; mutated by the loop.
+define void @test9(i64 %Size) nounwind ssp {
+bb.nph:
+ %Base = alloca i8, i32 10000
+ %Dest = alloca i8, i32 10000
+
+ %BaseAlias = call i8* @external(i8* %Base)
+ br label %for.body
+
+for.body: ; preds = %bb.nph, %for.body
+ %indvar = phi i64 [ 0, %bb.nph ], [ %indvar.next, %for.body ]
+ %I.0.014 = getelementptr i8* %Base, i64 %indvar
+ %DestI = getelementptr i8* %Dest, i64 %indvar
+ %V = load i8* %I.0.014, align 1
+ store i8 %V, i8* %DestI, align 1
+
+ ;; This store can clobber the input.
+ store i8 4, i8* %BaseAlias
+
+ %indvar.next = add i64 %indvar, 1
+ %exitcond = icmp eq i64 %indvar.next, %Size
+ br i1 %exitcond, label %for.end, label %for.body
+
+for.end: ; preds = %for.body, %entry
+ ret void
+; CHECK: @test9
+; CHECK-NOT: llvm.memcpy
+; CHECK: ret void
+}
+