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
diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 0d6df2f..641f9b0 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -2351,13 +2351,13 @@
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 @@
/// 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;