1 files changed, 28 insertions, 0 deletions
diff --git a/test/Transforms/LoopStrengthReduce/share_code_in_preheader.ll b/test/Transforms/LoopStrengthReduce/share_code_in_preheader.ll
new file mode 100644
index 0000000..d8316a5
--- /dev/null
+++ b/test/Transforms/LoopStrengthReduce/share_code_in_preheader.ll
@@ -0,0 +1,28 @@
+; RUN: llvm-upgrade < %s | llvm-as | opt -loop-reduce | llvm-dis | grep mul | wc -l | grep 1
+; LSR should not make two copies of the Q*L expression in the preheader!
+
+sbyte %test(sbyte* %A, sbyte* %B, int %L, int %Q, int %N.s) {
+entry:
+	%tmp.6 = mul int %Q, %L		; <int> [#uses=1]
+	%N = cast int %N.s to uint		; <uint> [#uses=1]
+	br label %no_exit
+
+no_exit:		; preds = %no_exit, %no_exit.preheader
+	%indvar.ui = phi uint [ 0, %entry], [ %indvar.next, %no_exit ]		; <uint> [#uses=2]
+	%Sum.0.0 = phi sbyte [ 0, %entry], [ %tmp.21, %no_exit ]		; <sbyte> [#uses=1]
+	%indvar = cast uint %indvar.ui to int		; <int> [#uses=1]
+	%N_addr.0.0 = sub int %N.s, %indvar		; <int> [#uses=1]
+	%tmp.8 = add int %N_addr.0.0, %tmp.6		; <int> [#uses=2]
+	%tmp.9 = getelementptr sbyte* %A, int %tmp.8		; <sbyte*> [#uses=1]
+	%tmp.10 = load sbyte* %tmp.9		; <sbyte> [#uses=1]
+	%tmp.17 = getelementptr sbyte* %B, int %tmp.8		; <sbyte*> [#uses=1]
+	%tmp.18 = load sbyte* %tmp.17		; <sbyte> [#uses=1]
+	%tmp.19 = sub sbyte %tmp.10, %tmp.18		; <sbyte> [#uses=1]
+	%tmp.21 = add sbyte %tmp.19, %Sum.0.0		; <sbyte> [#uses=2]
+	%indvar.next = add uint %indvar.ui, 1		; <uint> [#uses=2]
+	%exitcond = seteq uint %indvar.next, %N		; <bool> [#uses=1]
+	br bool %exitcond, label %loopexit, label %no_exit
+
+loopexit:
+	ret sbyte %tmp.21
+}