some comment improvements.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123243 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index ead4372..b3df926 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -2446,8 +2446,9 @@
return getMinusSCEV(AllOnes, V);
}
-/// getMinusSCEV - Return a SCEV corresponding to LHS - RHS.
-///
+/// getMinusSCEV - Return LHS-RHS. Minus is represented in SCEV as A+B*-1,
+/// and thus the HasNUW and HasNSW bits apply to the resultant add, not
+/// whether the sub would have overflowed.
const SCEV *ScalarEvolution::getMinusSCEV(const SCEV *LHS, const SCEV *RHS,
bool HasNUW, bool HasNSW) {
// Fast path: X - X --> 0.
@@ -4021,7 +4022,7 @@
cast<SCEVConstant>(RHSA->getOperand(1))->getValue();
// If the strides are equal, then this is just a (complex) loop invariant
- // comparison of a/b.
+ // comparison of a and b.
if (LHSStride == RHSStride)
return SE.getMinusSCEV(LHSA->getStart(), RHSA->getStart());