only factor from expressions whose uses are empty and whose
base is the right expression type.  This fixes PR5981.

llvm-svn: 93045
diff --git a/llvm/test/Transforms/Reassociate/crash.ll b/llvm/test/Transforms/Reassociate/crash.ll
index 12f8a37..060018d 100644
--- a/llvm/test/Transforms/Reassociate/crash.ll
+++ b/llvm/test/Transforms/Reassociate/crash.ll
@@ -2,7 +2,7 @@
 
 
 ; rdar://7507855
-define fastcc i32 @test() nounwind {
+define fastcc i32 @test1() nounwind {
 entry:
   %cond = select i1 undef, i32 1, i32 -1          ; <i32> [#uses=2]
   br label %for.cond
@@ -13,3 +13,21 @@
   %add896 = sub i32 0, %cond                      ; <i32> [#uses=0]
   ret i32 undef
 }
+
+; PR5981
+define i32 @test2() nounwind ssp {
+entry:
+  %0 = load i32* undef, align 4
+  %1 = mul nsw i32 undef, %0
+  %2 = mul nsw i32 undef, %0
+  %3 = add nsw i32 undef, %1
+  %4 = add nsw i32 %3, %2
+  %5 = add nsw i32 %4, 4
+  %6 = shl i32 %0, 3                              ; <i32> [#uses=1]
+  %7 = add nsw i32 %5, %6
+  br label %bb4.i9
+
+bb4.i9:                                           ; preds = %bb3.i7, %bb1.i25.i
+  %8 = add nsw i32 undef, %1
+  ret i32 0
+}