[LV] Perform recurrence sinking directly on VPlan.
This patch updates LV to sink recipes directly using the VPlan use
chains. The initial patch only moves sinking to be purely VPlan-based.
Follow-up patches will move legality checks to VPlan as well.
At the moment, there's a single test failure remaining.
Reviewed By: Ayal
Differential Revision: https://reviews.llvm.org/D142589
diff --git a/llvm/lib/Transforms/Vectorize/VPlanTransforms.h b/llvm/lib/Transforms/Vectorize/VPlanTransforms.h
index be0d8e7..bc1094d 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.h
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.h
@@ -25,6 +25,7 @@
class Loop;
class PredicatedScalarEvolution;
class TargetLibraryInfo;
+class VPBuilder;
struct VPlanTransforms {
/// Replaces the VPInstructions in \p Plan with corresponding
@@ -71,6 +72,13 @@
/// them with already existing recipes expanding the same SCEV expression.
static void removeRedundantExpandSCEVRecipes(VPlan &Plan);
+ /// Sink users of fixed-order recurrences after the recipe defining their
+ /// previous value. Then introduce FirstOrderRecurrenceSplice VPInstructions
+ /// to combine the value from the recurrence phis and previous values. The
+ /// current implementation assumes all users can be sunk after the previous
+ /// value, which is enforced by earlier legality checks.
+ static void adjustFixedOrderRecurrences(VPlan &Plan, VPBuilder &Builder);
+
/// Optimize \p Plan based on \p BestVF and \p BestUF. This may restrict the
/// resulting plan to \p BestVF and \p BestUF.
static void optimizeForVFAndUF(VPlan &Plan, ElementCount BestVF,
