[VPlan] Allow zero-operand m_VPInstruction (NFC) (#159550)

Author: artagnon

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -6902,11 +6902,9 @@ static bool planContainsAdditionalSimplifications(VPlan &Plan,
       // cost model won't cost it whilst the legacy will.
       if (auto *FOR = dyn_cast<VPFirstOrderRecurrencePHIRecipe>(&R)) {
         using namespace VPlanPatternMatch;
-        if (none_of(
-                FOR->users(),
-                match_fn(
-                    m_VPInstruction<VPInstruction::FirstOrderRecurrenceSplice>(
-                        m_VPValue(), m_VPValue()))))
+        if (none_of(FOR->users(),
+                    match_fn(m_VPInstruction<
+                             VPInstruction::FirstOrderRecurrenceSplice>())))
           return true;
       }
       // The VPlan-based cost model is more accurate for partial reduction and

llvm/lib/Transforms/Vectorize/VPlanPatternMatch.h

@@ -239,11 +239,9 @@ struct Recipe_match {
   }
 
   bool match(const VPRecipeBase *R) const {
-    if (std::tuple_size<Ops_t>::value == 0) {
-      assert(Opcode == VPInstruction::BuildVector &&
-             "can only match BuildVector with empty ops");
+    if (std::tuple_size_v<Ops_t> == 0) {
       auto *VPI = dyn_cast<VPInstruction>(R);
-      return VPI && VPI->getOpcode() == VPInstruction::BuildVector;
+      return VPI && VPI->getOpcode() == Opcode;
     }
 
     if ((!matchRecipeAndOpcode<RecipeTys>(R) && ...))

llvm/lib/Transforms/Vectorize/VPlanUnroll.cpp

@@ -317,8 +317,8 @@ void UnrollState::unrollRecipeByUF(VPRecipeBase &R) {
     // requiring it.
     if (isa<VPScalarIVStepsRecipe, VPWidenCanonicalIVRecipe,
             VPVectorPointerRecipe, VPVectorEndPointerRecipe>(Copy) ||
-        match(Copy, m_VPInstruction<VPInstruction::CanonicalIVIncrementForPart>(
-                        m_VPValue())))
+        match(Copy,
+              m_VPInstruction<VPInstruction::CanonicalIVIncrementForPart>()))
       Copy->addOperand(getConstantVPV(Part));
 
     if (isa<VPVectorPointerRecipe, VPVectorEndPointerRecipe>(R))

llvm/lib/Transforms/Vectorize/VPlanUtils.cpp

@@ -98,8 +98,7 @@ bool vputils::isUniformAcrossVFsAndUFs(VPValue *V) {
   VPRecipeBase *R = V->getDefiningRecipe();
   if (R && V->isDefinedOutsideLoopRegions()) {
     if (match(V->getDefiningRecipe(),
-              m_VPInstruction<VPInstruction::CanonicalIVIncrementForPart>(
-                  m_VPValue())))
+              m_VPInstruction<VPInstruction::CanonicalIVIncrementForPart>()))
       return false;
     return all_of(R->operands(), isUniformAcrossVFsAndUFs);
   }