[IR] Provide array with poison-generating metadata IDs.

[fhahn]

Add Metadata::PoisonGeneratingIDs containing IDs of poison-generating metadata to allow easier re-use.

[llvmbot]

@llvm/pr-subscribers-llvm-transforms

@llvm/pr-subscribers-llvm-ir

Author: Florian Hahn (fhahn)

Changes

Add Instruction::PoisonGeneratingMetadataIDs containing IDs of poison-generating metadata to allow easier re-use.

Currently it is a static const array in Instruction, maybe here's a better place?

---

Full diff: https://github.com/llvm/llvm-project/pull/123188.diff

2 Files Affected:

• (modified) llvm/include/llvm/IR/Instruction.h (+4)
• (modified) llvm/lib/IR/Instruction.cpp (+4-6)

diff --git a/llvm/include/llvm/IR/Instruction.h b/llvm/include/llvm/IR/Instruction.h
index aa480aa8d98636..645aa57d053e2e 100644
--- a/llvm/include/llvm/IR/Instruction.h
+++ b/llvm/include/llvm/IR/Instruction.h
@@ -503,6 +503,10 @@ class Instruction : public User,
   /// Determine whether the the nneg flag is set.
   bool hasNonNeg() const LLVM_READONLY;
 
+  /// Metadata IDs that may generate poison.
+  constexpr static const unsigned PoisonGeneratingMetadataIDs[] = {
+      LLVMContext::MD_range, LLVMContext::MD_nonnull, LLVMContext::MD_align};
+
   /// Return true if this operator has flags which may cause this instruction
   /// to evaluate to poison despite having non-poison inputs.
   bool hasPoisonGeneratingFlags() const LLVM_READONLY;
diff --git a/llvm/lib/IR/Instruction.cpp b/llvm/lib/IR/Instruction.cpp
index 147cd84125c8d1..12aefd8b1e96c1 100644
--- a/llvm/lib/IR/Instruction.cpp
+++ b/llvm/lib/IR/Instruction.cpp
@@ -458,9 +458,8 @@ void Instruction::dropPoisonGeneratingFlags() {
 }
 
 bool Instruction::hasPoisonGeneratingMetadata() const {
-  return hasMetadata(LLVMContext::MD_range) ||
-         hasMetadata(LLVMContext::MD_nonnull) ||
-         hasMetadata(LLVMContext::MD_align);
+  return any_of(PoisonGeneratingMetadataIDs,
+                [this](unsigned ID) { return hasMetadata(ID); });
 }
 
 bool Instruction::hasNonDebugLocLoopMetadata() const {
@@ -487,9 +486,8 @@ bool Instruction::hasNonDebugLocLoopMetadata() const {
 }
 
 void Instruction::dropPoisonGeneratingMetadata() {
-  eraseMetadata(LLVMContext::MD_range);
-  eraseMetadata(LLVMContext::MD_nonnull);
-  eraseMetadata(LLVMContext::MD_align);
+  for (unsigned ID : PoisonGeneratingMetadataIDs)
+    eraseMetadata(ID);
 }
 
 bool Instruction::hasPoisonGeneratingReturnAttributes() const {

[nikic]

Add Instruction::PoisonGeneratingMetadataIDs containing IDs of poison-generating metadata to allow easier re-use.

Currently it is a static const array in Instruction, maybe here's a better place?

Metadata::PoisonGeneratingIDs maybe? No strong opinion.

[fhahn]

Add Instruction::PoisonGeneratingMetadataIDs containing IDs of poison-generating metadata to allow easier re-use.
Currently it is a static const array in Instruction, maybe here's a better place?

Metadata::PoisonGeneratingIDs maybe? No strong opinion.

Moved there, as it is overall a bit more compact when used outside Instruction:: :)

[nikic]

LGTM

[dtcxzyw]

We can also use this array in ArgumentPromotion:

llvm-project/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp

Lines 256 to 264 in 8965dd4

	// Only transfer poison-generating metadata if we also have
	// !noundef.
	// TODO: Without !noundef, we could merge this metadata across
	// all promoted loads.
	if (LI->hasMetadata(LLVMContext::MD_noundef))
	LI->copyMetadata(*Pair.second.MustExecInstr,
	{LLVMContext::MD_range, LLVMContext::MD_nonnull,
	LLVMContext::MD_align});
	}

[fhahn]

We can also use this array in ArgumentPromotion:

llvm-project/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp

Lines 256 to 264 in 8965dd4

	// Only transfer poison-generating metadata if we also have
	// !noundef.
	// TODO: Without !noundef, we could merge this metadata across
	// all promoted loads.
	if (LI->hasMetadata(LLVMContext::MD_noundef))
	LI->copyMetadata(*Pair.second.MustExecInstr,
	{LLVMContext::MD_range, LLVMContext::MD_nonnull,
	LLVMContext::MD_align});
	}

Done, thanks!