[IndVars] Remove unreasonable checks in rewriteLoopExitValues

A piece of logic in rewriteLoopExitValues has a weird check on number of
users which allowed an unprofitable transform in case if an instruction has
more than 6 users.

Differential Revision: https://reviews.llvm.org/D51404
Reviewed By: etherzhhb

llvm-svn: 342444

1 files changed, 30 insertions, 0 deletions

diff --git a/llvm/test/Transforms/IndVarSimplify/dont-recompute.ll b/llvm/test/Transforms/IndVarSimplify/dont-recompute.ll
index e5ced0f2e4b..713a55154ba 100644
--- a/llvm/test/Transforms/IndVarSimplify/dont-recompute.ll
+++ b/llvm/test/Transforms/IndVarSimplify/dont-recompute.ll
@@ -67,3 +67,33 @@ for.end:                                          ; preds = %for.body
 ; CHECK-NEXT: ret i32 %add.lcssa
   ret i32 %add
 }
+
+; CHECK-LABEL: @test3(
+define void @test3(i32 %m) nounwind uwtable {
+entry:
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+  %i.06 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+  %a.05 = phi i32 [ 0, %entry ], [ %add, %for.body ]
+  %add = add i32 %a.05, %m
+  mul i32 %add, 1
+  mul i32 %add, 1
+  mul i32 %add, 1
+  mul i32 %add, 1
+  mul i32 %add, 1
+  mul i32 %add, 1
+; CHECK: tail call void @func(i32 %add)
+  tail call void @func(i32 %add)
+  %inc = add nsw i32 %i.06, 1
+  %exitcond = icmp eq i32 %inc, 186
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:                                          ; preds = %for.body
+; CHECK: for.end:
+; CHECK-NOT: mul i32 %m, 186
+; CHECK:%add.lcssa = phi i32 [ %add, %for.body ]
+; CHECK-NEXT: tail call void @func(i32 %add.lcssa)
+  tail call void @func(i32 %add)
+  ret void
+}