diff options
Diffstat (limited to 'lib/Transforms/Scalar/IndVarSimplify.cpp')
-rw-r--r-- | lib/Transforms/Scalar/IndVarSimplify.cpp | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp index c291f68bd6..c992f8c12a 100644 --- a/lib/Transforms/Scalar/IndVarSimplify.cpp +++ b/lib/Transforms/Scalar/IndVarSimplify.cpp @@ -897,15 +897,24 @@ const SCEVAddRecExpr *WidenIV::GetWideRecurrence(Instruction *NarrowUse) { return AddRec; } +/// This IV user cannot be widen. Replace this use of the original narrow IV +/// with a truncation of the new wide IV to isolate and eliminate the narrow IV. +static void truncateIVUse(NarrowIVDefUse DU, DominatorTree *DT) { + IRBuilder<> Builder(getInsertPointForUses(DU.NarrowUse, DU.NarrowDef, DT)); + Value *Trunc = Builder.CreateTrunc(DU.WideDef, DU.NarrowDef->getType()); + DU.NarrowUse->replaceUsesOfWith(DU.NarrowDef, Trunc); +} + /// WidenIVUse - Determine whether an individual user of the narrow IV can be /// widened. If so, return the wide clone of the user. Instruction *WidenIV::WidenIVUse(NarrowIVDefUse DU, SCEVExpander &Rewriter) { // Stop traversing the def-use chain at inner-loop phis or post-loop phis. if (isa<PHINode>(DU.NarrowUse) && - LI->getLoopFor(DU.NarrowUse->getParent()) != L) + LI->getLoopFor(DU.NarrowUse->getParent()) != L) { + truncateIVUse(DU, DT); return 0; - + } // Our raison d'etre! Eliminate sign and zero extension. if (IsSigned ? isa<SExtInst>(DU.NarrowUse) : isa<ZExtInst>(DU.NarrowUse)) { Value *NewDef = DU.WideDef; @@ -953,9 +962,7 @@ Instruction *WidenIV::WidenIVUse(NarrowIVDefUse DU, SCEVExpander &Rewriter) { // This user does not evaluate to a recurence after widening, so don't // follow it. Instead insert a Trunc to kill off the original use, // eventually isolating the original narrow IV so it can be removed. - IRBuilder<> Builder(getInsertPointForUses(DU.NarrowUse, DU.NarrowDef, DT)); - Value *Trunc = Builder.CreateTrunc(DU.WideDef, DU.NarrowDef->getType()); - DU.NarrowUse->replaceUsesOfWith(DU.NarrowDef, Trunc); + truncateIVUse(DU, DT); return 0; } // Assume block terminators cannot evaluate to a recurrence. We can't to |