[llvm-branch-commits] [llvm] [SPIRV] Drop the DebugTypeFunction operand cache. (PR #229486)

[Manuel Carrasco via llvm-branch-commits]

https://github.com/mgcarrasco updated https://github.com/llvm/llvm-project/pull/229486

>From a917948989efaad4dc8b0b29f8ca913f88e1ac5a Mon Sep 17 00:00:00 2001
From: Manuel Carrasco <Manuel.Carrasco at amd.com>
Date: Tue, 6 Oct 2026 08:03:06 -0500
Subject: [PATCH] [SPIRV] Drop the DebugTypeFunction operand cache.

Each DISubroutineType is already emitted once through DebugScopeRegs.
---
 .../SPIRV/SPIRVNonSemanticDebugHandler.cpp     | 18 ++----------------
 .../SPIRV/SPIRVNonSemanticDebugHandler.h       | 11 -----------
 .../debug-type-function-void-prototypes.ll     |  5 +++--
 3 files changed, 5 insertions(+), 29 deletions(-)

diff --git a/llvm/lib/Target/SPIRV/SPIRVNonSemanticDebugHandler.cpp b/llvm/lib/Target/SPIRV/SPIRVNonSemanticDebugHandler.cpp
index 8618fb9acbb7e..e63785c343c2c 100644
--- a/llvm/lib/Target/SPIRV/SPIRVNonSemanticDebugHandler.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVNonSemanticDebugHandler.cpp
@@ -348,7 +348,6 @@ void SPIRVNonSemanticDebugHandler::beginModule(Module *M) {
   ScalarTypeCache.clear();
   ScalarConstantCache.clear();
   ConstantValueRegs.clear();
-  DebugTypeFunctionCache.clear();
   DebugOperationCache.clear();
   DebugExpressionCache.clear();
   ModuleScopeIds.clear();
@@ -555,20 +554,6 @@ MCRegister SPIRVNonSemanticDebugHandler::emitExtInst(
   return Reg;
 }
 
-MCRegister SPIRVNonSemanticDebugHandler::getOrEmitDebugTypeFunction(
-    ArrayRef<MCRegister> Ops, MCRegister VoidTypeReg, MCRegister ExtInstSetReg,
-    SPIRV::ModuleAnalysisInfo &MAI) {
-  auto [It, Inserted] =
-      DebugTypeFunctionCache.try_emplace(SmallVector<MCRegister, 8>(Ops));
-  if (!Inserted)
-    return It->second;
-
-  MCRegister Reg = emitExtInst(SPIRV::NonSemanticExtInst::DebugTypeFunction,
-                               VoidTypeReg, ExtInstSetReg, Ops, MAI);
-  It->second = Reg;
-  return Reg;
-}
-
 MCRegister SPIRVNonSemanticDebugHandler::getOrEmitOpTypeVoidReg(
     SPIRV::ModuleAnalysisInfo &MAI) {
   if (!CachedOpTypeVoidReg.isValid())
@@ -985,7 +970,8 @@ SPIRVNonSemanticDebugHandler::emitDebugTypeFunctionForSubroutineType(
     }
   }
   return EmitResult::emitted(
-      getOrEmitDebugTypeFunction(Ops, VoidTypeReg, ExtInstSetReg, MAI));
+      emitExtInst(SPIRV::NonSemanticExtInst::DebugTypeFunction, VoidTypeReg,
+                  ExtInstSetReg, Ops, MAI));
 }
 
 // Match SPIRV-LLVM-Translator's selection logic for the Parent operand.
diff --git a/llvm/lib/Target/SPIRV/SPIRVNonSemanticDebugHandler.h b/llvm/lib/Target/SPIRV/SPIRVNonSemanticDebugHandler.h
index a96ac8e33afed..0a7690efbab7b 100644
--- a/llvm/lib/Target/SPIRV/SPIRVNonSemanticDebugHandler.h
+++ b/llvm/lib/Target/SPIRV/SPIRVNonSemanticDebugHandler.h
@@ -190,10 +190,6 @@ class SPIRVNonSemanticDebugHandler : public DebugHandlerBase {
   DenseMap<std::pair<const DIBasicType *, uint64_t>, MCRegister>
       ConstantValueRegs;
 
-  // Cache of already-emitted DebugTypeFunction instructions, keyed by operand
-  // ids (flags, return type, parameters).
-  DenseMap<SmallVector<MCRegister, 8>, MCRegister> DebugTypeFunctionCache;
-
   // Cache of already-emitted DebugOperation instructions, keyed by NonSemantic
   // opcode followed by the 32-bit operation arguments. Inline size 3 is the
   // spec maximum (opcode plus at most two operands: BitPiece, Fragment).
@@ -362,13 +358,6 @@ class SPIRVNonSemanticDebugHandler : public DebugHandlerBase {
                          ArrayRef<MCRegister> Operands,
                          SPIRV::ModuleAnalysisInfo &MAI);
 
-  /// Return a cached DebugTypeFunction id when \p Ops matches a prior emission,
-  /// otherwise emit and cache a new instruction.
-  MCRegister getOrEmitDebugTypeFunction(ArrayRef<MCRegister> Ops,
-                                        MCRegister VoidTypeReg,
-                                        MCRegister ExtInstSetReg,
-                                        SPIRV::ModuleAnalysisInfo &MAI);
-
   /// Return OpTypeVoid id for this module (lazy lookup / emit, then cache).
   MCRegister getOrEmitOpTypeVoidReg(SPIRV::ModuleAnalysisInfo &MAI);
 
diff --git a/llvm/test/CodeGen/SPIRV/debug-info/debug-type-function-void-prototypes.ll b/llvm/test/CodeGen/SPIRV/debug-info/debug-type-function-void-prototypes.ll
index d9f41f4cf0bab..10ef297e37876 100644
--- a/llvm/test/CodeGen/SPIRV/debug-info/debug-type-function-void-prototypes.ll
+++ b/llvm/test/CodeGen/SPIRV/debug-info/debug-type-function-void-prototypes.ll
@@ -2,13 +2,14 @@
 ; RUN: %if spirv-tools %{ llc --verify-machineinstrs --spirv-ext=+SPV_KHR_non_semantic_info -O0 -mtriple=spirv64-unknown-unknown %s -o - -filetype=obj | spirv-val %}
 
 ; Void function types in LLVM metadata may be written as an empty type list (!{}) or with an explicit
-; null return slot (!{null}); both should produce the same SPIR-V DebugTypeFunction (flags + void only).
+; null return slot (!{null}). Those are two DISubroutineType nodes, so each gets its own
+; DebugTypeFunction. Both instructions have the same operands: flags and OpTypeVoid.
 
 ; CHECK: [[ext:%[0-9]+]] = OpExtInstImport "NonSemantic.Shader.DebugInfo.100"
 ; CHECK-DAG: [[type_void:%[0-9]+]] = OpTypeVoid
 ; CHECK-DAG: [[type_int32:%[0-9]+]] = OpTypeInt 32 0
 ; CHECK-DAG: [[flag_zero:%[0-9]+]] = OpConstant [[type_int32]] 0{{$}}
-; CHECK-COUNT-1: OpExtInst [[type_void]] [[ext]] DebugTypeFunction [[flag_zero]] [[type_void]]
+; CHECK-COUNT-2: OpExtInst [[type_void]] [[ext]] DebugTypeFunction [[flag_zero]] [[type_void]]
 
 target triple = "spirv64-unknown-unknown"