Revert r139126 due to selfhost failures reported by buildbots.

llvm-svn: 139130

1 files changed, 2 insertions, 6 deletions

diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index a2cd38b4bf5..8859c3b22fb 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -5184,12 +5184,8 @@ ScalarEvolution::HowFarToZero(const SCEV *V, const Loop *L) {
   // Handle unitary steps, which cannot wraparound.
   // 1*N = -Start; -1*N = Start (mod 2^BW), so:
   //   N = Distance (as unsigned)
-  if (StepC->getValue()->equalsInt(1) || StepC->getValue()->isAllOnesValue()) {
-    ConstantRange CR = getUnsignedRange(Start);
-    const SCEV *MaxBECount = getConstant(CountDown ? CR.getUnsignedMax()
-                                                   : ~CR.getUnsignedMin());
-    return ExitLimit(Distance, MaxBECount);
-  }
+  if (StepC->getValue()->equalsInt(1) || StepC->getValue()->isAllOnesValue())
+    return Distance;
 
   // If the recurrence is known not to wraparound, unsigned divide computes the
   // back edge count. We know that the value will either become zero (and thus