From 79fec8116fe9d3a2ef4890c0a4dc433f41ac57b6 Mon Sep 17 00:00:00 2001
From: Nick Lewycky <nicholas@mxc.ca>
Date: Mon, 3 Oct 2011 05:14:59 +0000
Subject: [PATCH] Revert r140979 due to reports of bootstrap failure.

llvm-svn: 140980
---
 lib/Analysis/ScalarEvolution.cpp              | 12 +++-----
 .../ScalarEvolution/max-trip-count.ll         | 28 -------------------
 2 files changed, 4 insertions(+), 36 deletions(-)

diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index a630c7e710d..ea45e9d72c7 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -5119,7 +5119,7 @@ SolveQuadraticEquation(const SCEVAddRecExpr *AddRec, ScalarEvolution &SE) {
     // Compute the two solutions for the quadratic formula.
     // The divisions must be performed as signed divisions.
     APInt NegB(-B);
-    APInt TwoA(A << 1);
+    APInt TwoA( A << 1 );
     if (TwoA.isMinValue()) {
       const SCEV *CNC = SE.getCouldNotCompute();
       return std::make_pair(CNC, CNC);
@@ -5134,7 +5134,7 @@ SolveQuadraticEquation(const SCEVAddRecExpr *AddRec, ScalarEvolution &SE) {
 
     return std::make_pair(SE.getConstant(Solution1),
                           SE.getConstant(Solution2));
-  } // end APIntOps namespace
+    } // end APIntOps namespace
 }
 
 /// HowFarToZero - Return the number of times a backedge comparing the specified
@@ -5228,12 +5228,8 @@ 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
diff --git a/test/Analysis/ScalarEvolution/max-trip-count.ll b/test/Analysis/ScalarEvolution/max-trip-count.ll
index 0cdbdf57a64..843fb073087 100644
--- a/test/Analysis/ScalarEvolution/max-trip-count.ll
+++ b/test/Analysis/ScalarEvolution/max-trip-count.ll
@@ -70,31 +70,3 @@ for.end:                                          ; preds = %for.body, %for.cond
 }
 
 declare i32 @printf(i8*, ...)
-
-define void @test(i8* %a, i32 %n) nounwind {
-entry:
-  %cmp1 = icmp sgt i32 %n, 0
-  br i1 %cmp1, label %for.body.lr.ph, label %for.end
-
-for.body.lr.ph:                                   ; preds = %entry
-  %tmp = zext i32 %n to i64
-  br label %for.body
-
-for.body:                                         ; preds = %for.body, %for.body.lr.ph
-  %indvar = phi i64 [ %indvar.next, %for.body ], [ 0, %for.body.lr.ph ]
-  %arrayidx = getelementptr i8* %a, i64 %indvar
-  store i8 0, i8* %arrayidx, align 1
-  %indvar.next = add i64 %indvar, 1
-  %exitcond = icmp ne i64 %indvar.next, %tmp
-  br i1 %exitcond, label %for.body, label %for.cond.for.end_crit_edge
-
-for.cond.for.end_crit_edge:                       ; preds = %for.body
-  br label %for.end
-
-for.end:                                          ; preds = %for.cond.for.end_crit_edge, %entry
-  ret void
-}
-
-; CHECK: Determining loop execution counts for: @test
-; CHECK-NEXT: backedge-taken count is
-; CHECK-NEXT: max backedge-taken count is -1