Fix PR22222
The bug was introduced in r225282. r225282 assumed that sub X, Y is
the same as add X, -Y. This is not correct if we are going to upgrade
the sub to sub nuw. This change fixes the issue by making the
optimization ignore sub instructions.
Differential Revision: http://reviews.llvm.org/D6979
llvm-svn: 226075
diff --git a/llvm/test/Transforms/IndVarSimplify/pr22222.ll b/llvm/test/Transforms/IndVarSimplify/pr22222.ll
new file mode 100644
index 0000000..ccdfe53
--- /dev/null
+++ b/llvm/test/Transforms/IndVarSimplify/pr22222.ll
@@ -0,0 +1,46 @@
+; RUN: opt -indvars -S < %s | FileCheck %s
+
+@b = common global i32 0, align 4
+@c = common global i32 0, align 4
+@a = common global i32 0, align 4
+
+declare void @abort() #1
+
+; Function Attrs: nounwind ssp uwtable
+define i32 @main() {
+entry:
+ %a.promoted13 = load i32* @a, align 4
+ br label %for.cond1.preheader
+
+for.cond1.preheader: ; preds = %entry, %for.end
+ %or.lcssa14 = phi i32 [ %a.promoted13, %entry ], [ %or.lcssa, %for.end ]
+ %d.010 = phi i32 [ 1, %entry ], [ 0, %for.end ]
+ br label %for.body3
+
+for.body3: ; preds = %for.cond1.preheader, %for.body3
+ %inc12 = phi i32 [ 0, %for.cond1.preheader ], [ %inc, %for.body3 ]
+ %or11 = phi i32 [ %or.lcssa14, %for.cond1.preheader ], [ %or, %for.body3 ]
+; CHECK-NOT: sub nuw i32 %inc12, %d.010
+; CHECK: sub i32 %inc12, %d.010
+ %add = sub i32 %inc12, %d.010
+ %or = or i32 %or11, %add
+ %inc = add i32 %inc12, 1
+ br i1 false, label %for.body3, label %for.end
+
+for.end: ; preds = %for.body3
+ %or.lcssa = phi i32 [ %or, %for.body3 ]
+ br i1 false, label %for.cond1.preheader, label %for.end6
+
+for.end6: ; preds = %for.end
+ %or.lcssa.lcssa = phi i32 [ %or.lcssa, %for.end ]
+ store i32 %or.lcssa.lcssa, i32* @a, align 4
+ %cmp7 = icmp eq i32 %or.lcssa.lcssa, -1
+ br i1 %cmp7, label %if.end, label %if.then
+
+if.then: ; preds = %for.end6
+ tail call void @abort() #2
+ unreachable
+
+if.end: ; preds = %for.end6
+ ret i32 0
+}