Back out 60748 for now. It's breaking SPASS, 254.gap, and 464.h264ref.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60776 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index c9af6de..2b714de 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -2924,12 +2924,8 @@
   if (!R)
     return true;
 
-  if (isSigned) {
-    if (SC->getValue()->isOne())
-      return R->getValue()->isMaxValue(true);
-
+  if (isSigned)
     return true;  // XXX: because we don't have an sdiv scev.
-  }
 
   // If negative, it wraps around every iteration, but we don't care about that.
   APInt S = SC->getValue()->getValue().abs();