[SCEVExpander] Don't hoist divisions
Fixes PR30942.
llvm-svn: 286437
diff --git a/llvm/lib/Analysis/ScalarEvolutionExpander.cpp b/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
index 6ad766b..d94782a 100644
--- a/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -198,14 +198,21 @@
DebugLoc Loc = Builder.GetInsertPoint()->getDebugLoc();
SCEVInsertPointGuard Guard(Builder, this);
- // Move the insertion point out of as many loops as we can.
- while (const Loop *L = SE.LI.getLoopFor(Builder.GetInsertBlock())) {
- if (!L->isLoopInvariant(LHS) || !L->isLoopInvariant(RHS)) break;
- BasicBlock *Preheader = L->getLoopPreheader();
- if (!Preheader) break;
+ if (Opcode != Instruction::UDiv) {
+ // FIXME: There is alredy similar logic in expandCodeFor, we should see if
+ // this is actually needed here.
- // Ok, move up a level.
- Builder.SetInsertPoint(Preheader->getTerminator());
+ // Move the insertion point out of as many loops as we can.
+ while (const Loop *L = SE.LI.getLoopFor(Builder.GetInsertBlock())) {
+ if (!L->isLoopInvariant(LHS) || !L->isLoopInvariant(RHS))
+ break;
+ BasicBlock *Preheader = L->getLoopPreheader();
+ if (!Preheader)
+ break;
+
+ // Ok, move up a level.
+ Builder.SetInsertPoint(Preheader->getTerminator());
+ }
}
// If we haven't found this binop, insert it.
@@ -1663,31 +1670,34 @@
// Compute an insertion point for this SCEV object. Hoist the instructions
// as far out in the loop nest as possible.
Instruction *InsertPt = &*Builder.GetInsertPoint();
- for (Loop *L = SE.LI.getLoopFor(Builder.GetInsertBlock());;
- L = L->getParentLoop())
- if (SE.isLoopInvariant(S, L)) {
- if (!L) break;
- if (BasicBlock *Preheader = L->getLoopPreheader())
- InsertPt = Preheader->getTerminator();
- else {
- // LSR sets the insertion point for AddRec start/step values to the
- // block start to simplify value reuse, even though it's an invalid
- // position. SCEVExpander must correct for this in all cases.
- InsertPt = &*L->getHeader()->getFirstInsertionPt();
+ if (!isa<SCEVUDivExpr>(S)) {
+ for (Loop *L = SE.LI.getLoopFor(Builder.GetInsertBlock());;
+ L = L->getParentLoop())
+ if (SE.isLoopInvariant(S, L)) {
+ if (!L)
+ break;
+ if (BasicBlock *Preheader = L->getLoopPreheader())
+ InsertPt = Preheader->getTerminator();
+ else {
+ // LSR sets the insertion point for AddRec start/step values to the
+ // block start to simplify value reuse, even though it's an invalid
+ // position. SCEVExpander must correct for this in all cases.
+ InsertPt = &*L->getHeader()->getFirstInsertionPt();
+ }
+ } else {
+ // If the SCEV is computable at this level, insert it into the header
+ // after the PHIs (and after any other instructions that we've inserted
+ // there) so that it is guaranteed to dominate any user inside the loop.
+ if (L && SE.hasComputableLoopEvolution(S, L) && !PostIncLoops.count(L))
+ InsertPt = &*L->getHeader()->getFirstInsertionPt();
+ while (InsertPt->getIterator() != Builder.GetInsertPoint() &&
+ (isInsertedInstruction(InsertPt) ||
+ isa<DbgInfoIntrinsic>(InsertPt))) {
+ InsertPt = &*std::next(InsertPt->getIterator());
+ }
+ break;
}
- } else {
- // If the SCEV is computable at this level, insert it into the header
- // after the PHIs (and after any other instructions that we've inserted
- // there) so that it is guaranteed to dominate any user inside the loop.
- if (L && SE.hasComputableLoopEvolution(S, L) && !PostIncLoops.count(L))
- InsertPt = &*L->getHeader()->getFirstInsertionPt();
- while (InsertPt->getIterator() != Builder.GetInsertPoint() &&
- (isInsertedInstruction(InsertPt) ||
- isa<DbgInfoIntrinsic>(InsertPt))) {
- InsertPt = &*std::next(InsertPt->getIterator());
- }
- break;
- }
+ }
// Check to see if we already expanded this here.
auto I = InsertedExpressions.find(std::make_pair(S, InsertPt));