[llvm] [VPlan] Handle some VPInstructions in mayReadFromMemory (PR #120058)

[Florian Hahn via llvm-commits]

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@@ -115,6 +115,25 @@ bool VPRecipeBase::mayWriteToMemory() const {
 
 bool VPRecipeBase::mayReadFromMemory() const {
   switch (getVPDefID()) {
+  case VPInstructionSC:
+    if (Instruction::isBinaryOp(cast<VPInstruction>(this)->getOpcode()))
+      return false;
+    switch (cast<VPInstruction>(this)->getOpcode()) {
+    case Instruction::Or:
+    case Instruction::ICmp:
+    case Instruction::Select:
+    case VPInstruction::AnyOf:
+    case VPInstruction::Not:
+    case VPInstruction::CalculateTripCountMinusVF:
+    case VPInstruction::CanonicalIVIncrementForPart:
+    case VPInstruction::ExtractFromEnd:
+    case VPInstruction::FirstOrderRecurrenceSplice:
+    case VPInstruction::LogicalAnd:
+    case VPInstruction::PtrAdd:
+      return false;
+    default:
+      return true;
+    }
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fhahn wrote:

Those effectively check if the VPInstruction access memory (either reading or writing). Could you move it to something like `VPInstruction::mayReadOrWriteFromMemory()` and use it for both `VPRecipeBase::mayReadFromMemory` and `VPRecipeBase::mayWriteToMemory`, so it is automatically keept in sync?

https://github.com/llvm/llvm-project/pull/120058