[llvm] [VPlan] Implement printing VPIRMetadata. (PR #168385)

[Florian Hahn via llvm-commits]

https://github.com/fhahn updated https://github.com/llvm/llvm-project/pull/168385

>From 6c155f66e9b2870ef3af01ca46f952949c28a626 Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo at fhahn.com>
Date: Wed, 19 Nov 2025 15:44:09 +0000
Subject: [PATCH] [VPlan] Implement printing VPIRMetadata.

Implement and use debug printing for VPIRMetadata.
---
 llvm/lib/Transforms/Vectorize/VPlan.h         | 10 +++++++
 .../lib/Transforms/Vectorize/VPlanRecipes.cpp | 27 +++++++++++++++++++
 .../LoopVectorize/vplan-printing-metadata.ll  | 18 ++++++-------
 3 files changed, 46 insertions(+), 9 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index 13582f8bd2d62..4cb0a99ee65ba 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -1020,6 +1020,11 @@ class VPIRMetadata {
         find_if(Metadata, [Kind](const auto &P) { return P.first == Kind; });
     return It != Metadata.end() ? It->second : nullptr;
   }
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+  /// Print metadata with node IDs.
+  void print(raw_ostream &O, const VPlan *Plan) const;
+#endif
 };
 
 /// This is a concrete Recipe that models a single VPlan-level instruction.
@@ -4446,6 +4451,11 @@ 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 7c9302860a3b5..296ad27678700 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -497,6 +497,11 @@ void VPRecipeBase::print(raw_ostream &O, const Twine &Indent,
     O << ", !dbg ";
     DL.print(O);
   }
+
+  if (auto *Metadata = dyn_cast<VPIRMetadata>(this)) {
+    if (const VPBasicBlock *Parent = getParent())
+      Metadata->print(O, Parent->getPlan());
+  }
 }
 #endif
 
@@ -1695,6 +1700,28 @@ void VPIRMetadata::intersect(const VPIRMetadata &Other) {
   Metadata = std::move(MetadataIntersection);
 }
 
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+void VPIRMetadata::print(raw_ostream &O, const VPlan *Plan) const {
+  if (Metadata.empty() || !Plan)
+    return;
+
+  const Module &M = Plan->getModule();
+  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 << ")";
+}
+#endif
+
 void VPWidenCallRecipe::execute(VPTransformState &State) {
   assert(State.VF.isVector() && "not widening");
   assert(Variant != nullptr && "Can't create vector function.");
diff --git a/llvm/test/Transforms/LoopVectorize/vplan-printing-metadata.ll b/llvm/test/Transforms/LoopVectorize/vplan-printing-metadata.ll
index 857b9131a0b8c..fb49e94ee67bc 100644
--- a/llvm/test/Transforms/LoopVectorize/vplan-printing-metadata.ll
+++ b/llvm/test/Transforms/LoopVectorize/vplan-printing-metadata.ll
@@ -7,11 +7,11 @@ define void @test_widen_metadata(ptr noalias %A, ptr noalias %B, i32 %n) {
 ; CHECK:      VPlan 'Initial VPlan for VF={4},UF>=1' {
 ; CHECK:      <x1> vector loop: {
 ; CHECK:        vector.body:
-; CHECK:          WIDEN ir<%lv> = load vp<{{.*}}>
-; CHECK:          WIDEN-CAST ir<%conv> = sitofp ir<%lv> to float
-; CHECK:          WIDEN ir<%mul> = fmul ir<%conv>, ir<2.000000e+00>
+; CHECK:          WIDEN ir<%lv> = load vp<{{.*}}> (!tbaa !{{[0-9]+}})
+; CHECK:          WIDEN-CAST ir<%conv> = sitofp ir<%lv> to float (!fpmath !{{[0-9]+}})
+; CHECK:          WIDEN ir<%mul> = fmul ir<%conv>, ir<2.000000e+00> (!fpmath !{{[0-9]+}})
 ; CHECK:          WIDEN-CAST ir<%conv.back> = fptosi ir<%mul> to i32
-; CHECK:          WIDEN store vp<{{.*}}>, ir<%conv.back>
+; CHECK:          WIDEN store vp<{{.*}}>, ir<%conv.back> (!tbaa !{{[0-9]+}})
 ;
 entry:
   br label %loop
@@ -40,9 +40,9 @@ define void @test_intrinsic_with_metadata(ptr noalias %A, ptr noalias %B, i32 %n
 ; CHECK:      VPlan 'Initial VPlan for VF={4},UF>=1' {
 ; CHECK:      <x1> vector loop: {
 ; CHECK:        vector.body:
-; CHECK:          WIDEN ir<%lv> = load vp<{{.*}}>
-; CHECK:          WIDEN-INTRINSIC ir<%sqrt> = call llvm.sqrt(ir<%lv>)
-; CHECK:          WIDEN store vp<{{.*}}>, ir<%sqrt>
+; CHECK:          WIDEN ir<%lv> = load vp<{{.*}}> (!tbaa !{{[0-9]+}})
+; CHECK:          WIDEN-INTRINSIC ir<%sqrt> = call llvm.sqrt(ir<%lv>) (!fpmath !{{[0-9]+}})
+; CHECK:          WIDEN store vp<{{.*}}>, ir<%sqrt> (!tbaa !{{[0-9]+}})
 ;
 entry:
   br label %loop
@@ -67,11 +67,11 @@ define void @test_widen_with_multiple_metadata(ptr noalias %A, ptr noalias %B, i
 ; CHECK:      VPlan 'Initial VPlan for VF={4},UF>=1' {
 ; CHECK:      <x1> vector loop: {
 ; CHECK:        vector.body:
-; CHECK:          WIDEN ir<%lv> = load vp<{{.*}}>
+; CHECK:          WIDEN ir<%lv> = load vp<{{.*}}> (!tbaa !{{[0-9]+}})
 ; CHECK:          WIDEN-CAST ir<%conv> = sitofp ir<%lv> to float
 ; CHECK:          WIDEN ir<%mul> = fmul ir<%conv>, ir<2.000000e+00>
 ; CHECK:          WIDEN-CAST ir<%conv.back> = fptosi ir<%mul> to i32
-; CHECK:          WIDEN store vp<{{.*}}>, ir<%conv.back>
+; CHECK:          WIDEN store vp<{{.*}}>, ir<%conv.back> (!tbaa !{{[0-9]+}})
 ;
 entry:
   br label %loop