[PATCH] D133666: pVplan] Add VPValue::isDefinedOutsideVectorRegions helper (NFC).

[Florian Hahn via Phabricator via llvm-commits]

fhahn created this revision.
fhahn added reviewers: Ayal, gilr, rengolin, reames.
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@Ayal suggested a better named helper than using `!getDef()` to check if
a value is invariant across all parts.

The property we are using here is that the VPValue is defined outside
any vector loop region. There's a TODO left to handle recipes defined in
pre-header blocks.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D133666

Files:
  llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
  llvm/lib/Transforms/Vectorize/VPlan.h
  llvm/lib/Transforms/Vectorize/VPlanValue.h


Index: llvm/lib/Transforms/Vectorize/VPlanValue.h
===================================================================
--- llvm/lib/Transforms/Vectorize/VPlanValue.h
+++ llvm/lib/Transforms/Vectorize/VPlanValue.h
@@ -198,6 +198,11 @@
            "VPValue is not a live-in; it is defined by a VPDef inside a VPlan");
     return getUnderlyingValue();
   }
+
+  /// Returns true if the VPValue is defined outside any vector regions, i.e. it
+  /// is a live-in value.
+  /// TODO: Also handle recipes defined in pre-header blocks.
+  bool isDefinedOutsideVectorRegions() const { return !getDef(); }
 };
 
 typedef DenseMap<Value *, VPValue *> Value2VPValueTy;
Index: llvm/lib/Transforms/Vectorize/VPlan.h
===================================================================
--- llvm/lib/Transforms/Vectorize/VPlan.h
+++ llvm/lib/Transforms/Vectorize/VPlan.h
@@ -3055,7 +3055,7 @@
   if (auto *Def = VPV->getDef()) {
     if (auto Rep = dyn_cast<VPReplicateRecipe>(Def))
       return Rep->isUniform();
-    return false;
+    return VPV->isDefinedOutsideVectorRegions();
   }
   // A value without a def is external to vplan and thus uniform.
   return true;
Index: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
===================================================================
--- llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -9644,7 +9644,9 @@
     // If the recipe is uniform across all parts (instead of just per VF), only
     // generate a single instance.
     if ((isa<LoadInst>(UI) || isa<StoreInst>(UI)) &&
-        all_of(operands(), [](VPValue *Op) { return !Op->getDef(); })) {
+        all_of(operands(), [](VPValue *Op) {
+          return Op->isDefinedOutsideVectorRegions();
+        })) {
       State.ILV->scalarizeInstruction(UI, this, VPIteration(0, 0), IsPredicated,
                                       State);
       if (user_begin() != user_end()) {


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