new testcase

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23312 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 28 insertions, 0 deletions

diff --git a/test/Transforms/LoopStrengthReduce/use_postinc_value_outside_loop.ll b/test/Transforms/LoopStrengthReduce/use_postinc_value_outside_loop.ll
new file mode 100644
index 0000000000..42bbbcb50c
--- /dev/null
+++ b/test/Transforms/LoopStrengthReduce/use_postinc_value_outside_loop.ll
@@ -0,0 +1,28 @@
+; RUN: llvm-as < %s | opt -loop-reduce | llvm-dis | grep 'add uint %iv..inc, 1'
+;
+; Make sure that the use of the IV outside of the loop (the store) uses the 
+; post incremented value of the IV, not the preincremented value.  This 
+; prevents the loop from having to keep the post and pre-incremented value
+; around for the duration of the loop, adding a copy and an extra register
+; to the loop.
+
+declare bool %pred(int %X)
+
+void %test([700 x int]* %nbeaux_.0__558, int* %i_.16574) {
+then.0:
+        br label %no_exit.2
+
+no_exit.2:              ; preds = %no_exit.2, %then.0
+        %indvar630 = phi uint [ 0, %then.0 ], [ %indvar.next631, %no_exit.2 ]           ; <uint> [#uses=3]
+        %indvar630 = cast uint %indvar630 to int                ; <int> [#uses=1]
+        %tmp.38 = getelementptr [700 x int]* %nbeaux_.0__558, int 0, uint %indvar630            ; <int*> [#uses=1]
+        store int 0, int* %tmp.38
+        %inc.2 = add int %indvar630, 2          ; <int> [#uses=2]
+        %tmp.34 = call bool %pred(int %indvar630)
+        %indvar.next631 = add uint %indvar630, 1                ; <uint> [#uses=1]
+        br bool %tmp.34, label %no_exit.2, label %loopexit.2.loopexit
+
+loopexit.2.loopexit:            ; preds = %no_exit.2
+        store int %inc.2, int* %i_.16574
+        ret void
+}