[llvm] [VPlan] Implement printing VPIRMetadata. (PR #165825)

[Florian Hahn via llvm-commits]

https://github.com/fhahn updated https://github.com/llvm/llvm-project/pull/165825

>From bcd6751e244e7af6eea67f64632a367027b53f3f Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo at fhahn.com>
Date: Fri, 31 Oct 2025 04:34:53 +0000
Subject: [PATCH] [VPlan] Implement printing VPIRMetadata.

Implement and use debug printing for VPIRMetadata.
---
 llvm/lib/Transforms/Vectorize/VPlan.h         |  8 ++++++
 .../lib/Transforms/Vectorize/VPlanRecipes.cpp | 26 +++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index 1f10058ab4a9a..79583ce34c74d 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -968,6 +968,9 @@ class VPIRMetadata {
   /// Intersect this VPIRMetada object with \p MD, keeping only metadata
   /// nodes that are common to both.
   void intersect(const VPIRMetadata &MD);
+
+  /// Print metadata with node IDs.
+  void print(raw_ostream &O, const Module &M) const;
 };
 
 /// This is a concrete Recipe that models a single VPlan-level instruction.
@@ -4268,6 +4271,11 @@ class VPlan {
   /// Return the VPIRBasicBlock wrapping the header of the scalar loop.
   VPIRBasicBlock *getScalarHeader() const { return ScalarHeader; }
 
+  /// Return the Module from the scalar header.
+  const Module &getModule() const {
+    return *ScalarHeader->getIRBasicBlock()->getModule();
+  }
+
   /// Return an ArrayRef containing VPIRBasicBlocks wrapping the exit blocks of
   /// the original scalar loop.
   ArrayRef<VPIRBasicBlock *> getExitBlocks() const { return ExitBlocks; }
diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index bde62dd6dd4bc..3feedafde8049 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -1443,6 +1443,7 @@ void VPInstruction::print(raw_ostream &O, const Twine &Indent,
 
   printFlags(O);
   printOperands(O, SlotTracker);
+  VPIRMetadata::print(O, getParent()->getPlan()->getModule());
 
   if (auto DL = getDebugLoc()) {
     O << ", !dbg ";
@@ -1669,6 +1670,25 @@ void VPIRMetadata::intersect(const VPIRMetadata &Other) {
   Metadata = std::move(MetadataIntersection);
 }
 
+void VPIRMetadata::print(raw_ostream &O, const Module &M) const {
+  if (Metadata.empty())
+    return;
+
+  SmallVector<StringRef, 8> MDNames;
+  M.getContext().getMDKindNames(MDNames);
+
+  O << " (";
+  interleaveComma(Metadata, O, [&](const auto &KindNodePair) {
+    auto [Kind, Node] = KindNodePair;
+    assert(Kind != 0 && "Debug metadata should not be managed by VPIRMetadata");
+    assert(Kind < MDNames.size() && !MDNames[Kind].empty() &&
+           "Unexpected unnamed metadata kind");
+    O << "!" << MDNames[Kind] << " ";
+    Node->printAsOperand(O, &M);
+  });
+  O << ")";
+}
+
 void VPWidenCallRecipe::execute(VPTransformState &State) {
   assert(State.VF.isVector() && "not widening");
   assert(Variant != nullptr && "Can't create vector function.");
@@ -1729,6 +1749,7 @@ void VPWidenCallRecipe::print(raw_ostream &O, const Twine &Indent,
     Op->printAsOperand(O, SlotTracker);
   });
   O << ")";
+  VPIRMetadata::print(O, getParent()->getPlan()->getModule());
 
   O << " (using library function";
   if (Variant->hasName())
@@ -1863,6 +1884,7 @@ void VPWidenIntrinsicRecipe::print(raw_ostream &O, const Twine &Indent,
     Op->printAsOperand(O, SlotTracker);
   });
   O << ")";
+  VPIRMetadata::print(O, getParent()->getPlan()->getModule());
 }
 #endif
 
@@ -2255,6 +2277,7 @@ void VPWidenRecipe::print(raw_ostream &O, const Twine &Indent,
   O << " = " << Instruction::getOpcodeName(Opcode);
   printFlags(O);
   printOperands(O, SlotTracker);
+  VPIRMetadata::print(O, getParent()->getPlan()->getModule());
 }
 #endif
 
@@ -2336,6 +2359,7 @@ void VPWidenCastRecipe::print(raw_ostream &O, const Twine &Indent,
   printFlags(O);
   printOperands(O, SlotTracker);
   O << " to " << *getResultType();
+  VPIRMetadata::print(O, getParent()->getPlan()->getModule());
 }
 #endif
 
@@ -3618,6 +3642,7 @@ void VPWidenLoadRecipe::print(raw_ostream &O, const Twine &Indent,
   printAsOperand(O, SlotTracker);
   O << " = load ";
   printOperands(O, SlotTracker);
+  VPIRMetadata::print(O, getParent()->getPlan()->getModule());
 }
 #endif
 
@@ -3739,6 +3764,7 @@ void VPWidenStoreRecipe::print(raw_ostream &O, const Twine &Indent,
                                VPSlotTracker &SlotTracker) const {
   O << Indent << "WIDEN store ";
   printOperands(O, SlotTracker);
+  VPIRMetadata::print(O, getParent()->getPlan()->getModule());
 }
 #endif