1 files changed, 23 insertions, 8 deletions
diff --git a/test/Transforms/Reassociate/subtest.ll b/test/Transforms/Reassociate/subtest.ll
index 4c63d12..e6263d8 100644
--- a/test/Transforms/Reassociate/subtest.ll
+++ b/test/Transforms/Reassociate/subtest.ll
@@ -1,11 +1,26 @@
-; With sub reassociation, constant folding can eliminate the 12 and -12 constants.
-;
-; RUN: opt < %s -reassociate -instcombine -S | not grep 12
+; RUN: opt < %s -reassociate -instcombine -S | FileCheck %s
 
-define i32 @test(i32 %A, i32 %B) {
-	%X = add i32 -12, %A		; <i32> [#uses=1]
-	%Y = sub i32 %X, %B		; <i32> [#uses=1]
-	%Z = add i32 %Y, 12		; <i32> [#uses=1]
-	ret i32 %Z
+; With sub reassociation, constant folding can eliminate the 12 and -12 constants.
+define i32 @test1(i32 %A, i32 %B) {
+; CHECK-LABEL: @test1
+; CHECK-NEXT: %Z = sub i32 %A, %B
+; CHECK-NEXT: ret i32 %Z
+  %X = add i32 -12, %A
+  %Y = sub i32 %X, %B
+  %Z = add i32 %Y, 12
+  ret i32 %Z
 }
 
+; PR2047
+; With sub reassociation, constant folding can eliminate the uses of %a.
+define i32 @test2(i32 %a, i32 %b, i32 %c) nounwind  {
+; CHECK-LABEL: @test2
+; CHECK-NEXT: %sum = add i32 %c, %b
+; CHECK-NEXT: %tmp7 = sub i32 0, %sum
+; CHECK-NEXT: ret i32 %tmp7
+
+  %tmp3 = sub i32 %a, %b
+  %tmp5 = sub i32 %tmp3, %c
+  %tmp7 = sub i32 %tmp5, %a
+  ret i32 %tmp7
+}