Fill in some holes in ScalarEvolution's loop iteration condition
analysis. This allows indvars to emit a simpler loop trip count
expression.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76085 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index 7c68f89..dcd6558 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -960,6 +960,22 @@
return getAddRecExpr(getSignExtendExpr(Start, Ty),
getSignExtendExpr(Step, Ty),
L);
+
+ // Similar to above, only this time treat the step value as unsigned.
+ // This covers loops that count up with an unsigned step.
+ const SCEV *UMul =
+ getMulExpr(CastedMaxBECount,
+ getTruncateOrZeroExtend(Step, Start->getType()));
+ Add = getAddExpr(Start, UMul);
+ OperandExtendedAdd =
+ getAddExpr(getZeroExtendExpr(Start, WideTy),
+ getMulExpr(getZeroExtendExpr(CastedMaxBECount, WideTy),
+ getZeroExtendExpr(Step, WideTy)));
+ if (getZeroExtendExpr(Add, WideTy) == OperandExtendedAdd)
+ // Return the expression with the addrec on the outside.
+ return getAddRecExpr(getSignExtendExpr(Start, Ty),
+ getZeroExtendExpr(Step, Ty),
+ L);
}
// If the backedge is guarded by a comparison with the pre-inc value
@@ -4248,7 +4264,7 @@
switch (Pred) {
default:
- assert(0 && "Unexpected ICmpInst::Predicate value!");
+ llvm_unreachable("Unexpected ICmpInst::Predicate value!");
break;
case ICmpInst::ICMP_SGT:
Pred = ICmpInst::ICMP_SLT;
@@ -4556,23 +4572,32 @@
const SCEV *FoundLHS,
const SCEV *FoundRHS) {
switch (Pred) {
- default: break;
+ default: llvm_unreachable("Unexpected ICmpInst::Predicate value!");
+ case ICmpInst::ICMP_EQ:
+ case ICmpInst::ICMP_NE:
+ if (HasSameValue(LHS, FoundLHS) && HasSameValue(RHS, FoundRHS))
+ return true;
+ break;
case ICmpInst::ICMP_SLT:
+ case ICmpInst::ICMP_SLE:
if (isKnownPredicate(ICmpInst::ICMP_SLE, LHS, FoundLHS) &&
isKnownPredicate(ICmpInst::ICMP_SGE, RHS, FoundRHS))
return true;
break;
case ICmpInst::ICMP_SGT:
+ case ICmpInst::ICMP_SGE:
if (isKnownPredicate(ICmpInst::ICMP_SGE, LHS, FoundLHS) &&
isKnownPredicate(ICmpInst::ICMP_SLE, RHS, FoundRHS))
return true;
break;
case ICmpInst::ICMP_ULT:
+ case ICmpInst::ICMP_ULE:
if (isKnownPredicate(ICmpInst::ICMP_ULE, LHS, FoundLHS) &&
isKnownPredicate(ICmpInst::ICMP_UGE, RHS, FoundRHS))
return true;
break;
case ICmpInst::ICMP_UGT:
+ case ICmpInst::ICMP_UGE:
if (isKnownPredicate(ICmpInst::ICMP_UGE, LHS, FoundLHS) &&
isKnownPredicate(ICmpInst::ICMP_ULE, RHS, FoundRHS))
return true;