[llvm] [LV] Ignore some costs when loop gets fully unrolled (PR #106699)
Igor Kirillov via llvm-commits
llvm-commits at lists.llvm.org
Fri Nov 15 08:45:45 PST 2024
================
@@ -2663,6 +2663,33 @@ static Value *getExpandedStep(const InductionDescriptor &ID,
return I->second;
}
+/// Knowing that loop \p L would be fully unrolled after vectorisation, add
+/// instructions that will get simplified and thus should not have any cost to
+/// \p InstsToIgnore
+static void AddFullyUnrolledInstructionsToIgnore(
+ Loop *L, const LoopVectorizationLegality::InductionList &IL,
+ SmallPtrSetImpl<Instruction *> &InstsToIgnore) {
+ auto *Cmp = L->getLatchCmpInst();
+ if (!Cmp)
+ return;
+ InstsToIgnore.insert(Cmp);
+ for (const auto &[IV, IndDesc] : IL) {
+ // Get next iteration value of the induction variable
+ Instruction *IVInst =
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igogo-x86 wrote:
Which instructions could that be? We have only PHINodes in the IV chain unprocessed, but they already have zero cost
https://github.com/llvm/llvm-project/pull/106699
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