Rename ScalarEvolution's getIterationCount to getBackedgeTakenCount,

to more accurately describe what it does. Expand its doxygen comment
to describe what the backedge-taken count is and how it differs
from the actual iteration count of the loop. Adjust names and
comments in associated code accordingly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65382 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 7 deletions

diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 0d6df2fbae..641f9b0e5c 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -2351,13 +2351,13 @@ ICmpInst *LoopStrengthReduce::OptimizeSMax(Loop *L, ICmpInst *Cond,
   SelectInst *Sel = dyn_cast<SelectInst>(Cond->getOperand(1));
   if (!Sel || !Sel->hasOneUse()) return Cond;
 
-  SCEVHandle IterationCount = SE->getIterationCount(L);
-  if (isa<SCEVCouldNotCompute>(IterationCount))
+  SCEVHandle BackedgeTakenCount = SE->getBackedgeTakenCount(L);
+  if (isa<SCEVCouldNotCompute>(BackedgeTakenCount))
     return Cond;
-  SCEVHandle One = SE->getIntegerSCEV(1, IterationCount->getType());
+  SCEVHandle One = SE->getIntegerSCEV(1, BackedgeTakenCount->getType());
 
-  // Adjust for an annoying getIterationCount quirk.
-  IterationCount = SE->getAddExpr(IterationCount, One);
+  // Add one to the backedge-taken count to get the trip count.
+  SCEVHandle IterationCount = SE->getAddExpr(BackedgeTakenCount, One);
 
   // Check for a max calculation that matches the pattern.
   SCEVSMaxExpr *SMax = dyn_cast<SCEVSMaxExpr>(IterationCount);
@@ -2412,8 +2412,8 @@ ICmpInst *LoopStrengthReduce::OptimizeSMax(Loop *L, ICmpInst *Cond,
 /// inside the loop then try to eliminate the cast opeation.
 void LoopStrengthReduce::OptimizeShadowIV(Loop *L) {
 
-  SCEVHandle IterationCount = SE->getIterationCount(L);
-  if (isa<SCEVCouldNotCompute>(IterationCount))
+  SCEVHandle BackedgeTakenCount = SE->getBackedgeTakenCount(L);
+  if (isa<SCEVCouldNotCompute>(BackedgeTakenCount))
     return;
 
   for (unsigned Stride = 0, e = StrideOrder.size(); Stride != e;