Fix parameter decoration metadata overwrite in entry-point wrapper

In the entry-point wrapper pattern two SPIR-V functions map to the same
LLVM function; only one carries decorated parameters.
transOCLMetadata unconditionally set spirv.ParameterDecorations for both,
so the undecorated function could overwrite the decorated one's metadata.
Skip the write when the current function has no decorations and metadata
is already present.

AI-assisted: Claude Sonnet 4.6 (commercial SaaS)

Author: vmaksimo

lib/SPIRV/SPIRVReader.cpp

@@ -4593,8 +4593,13 @@ void SPIRVToLLVM::transFunctionDecorationsToMetadata(SPIRVFunction *BF,
   BF->foreachArgument([&](SPIRVFunctionParameter *Arg) {
     TotalParameterDecorations += Arg->getNumDecorations();
   });
-  if (TotalParameterDecorations == 0)
-    return;
+  // In the entry-point wrapper pattern two SPIR-V functions map to the same
+  // LLVM function; only one carries decorated parameters.  Skip the
+  // undecorated function so it cannot overwrite the decorated one.
+  if (TotalParameterDecorations == 0) {
+    if (F->hasMetadata(SPIRV_MD_PARAMETER_DECORATIONS))
+      return;
+  }
 
   // Generate metadata for spirv.ParameterDecorations
   addKernelArgumentMetadata(Context, SPIRV_MD_PARAMETER_DECORATIONS, BF, F,

test/extensions/INTEL/SPV_INTEL_cache_controls/cache-controls-entry-point-wrapper.spt

@@ -0,0 +1,42 @@
+; Verify that CacheControlLoadINTEL decoration on a FunctionParameter
+; survives reverse translation of the entry-point wrapper pattern.
+
+; RUN: llvm-spirv -spirv-text --to-binary %s -o %t.spv
+; RUN: spirv-val %t.spv
+; RUN: llvm-spirv -spirv-text -r --spirv-target-env=SPV-IR %s -o - | llvm-dis | FileCheck %s --check-prefix=CHECK-LLVM
+
+; CHECK-LLVM: spirv.ParameterDecorations ![[#ParamDecs:]]
+; CHECK-LLVM: ![[#ParamDecs]] = !{![[#FirstParam:]]}
+; CHECK-LLVM: ![[#FirstParam]] = !{![[#DecoNode:]]}
+; CHECK-LLVM: ![[#DecoNode]] = !{i32 6442, i32 0, i32 1}
+
+119734787 66560 393230 14 0
+2 Capability Addresses
+2 Capability Linkage
+2 Capability Kernel
+2 Capability CacheControlsINTEL
+8 Extension "SPV_INTEL_cache_controls"
+5 ExtInstImport 1 "OpenCL.std"
+3 MemoryModel 2 2
+5 EntryPoint 6 9 "test"
+3 Source 4 100000
+4 TypeInt 2 32 0
+2 TypeVoid 3
+4 TypePointer 5 5 2
+4 TypeFunction 6 3 5
+6 Decorate 4 LinkageAttributes "test" Export
+5 Decorate 7 CacheControlLoadINTEL 0 1
+
+5 Function 3 4 0 6
+3 FunctionParameter 5 7
+2 Label 8
+4 Load 2 13 7
+1 Return
+1 FunctionEnd
+
+5 Function 3 9 0 6
+3 FunctionParameter 5 10
+2 Label 11
+5 FunctionCall 3 12 4 10
+1 Return
+1 FunctionEnd

test/extensions/INTEL/SPV_INTEL_subgroup_buffer_prefetch/subgroup_buffer_prefetch_with_cache_controls.ll

@@ -10,9 +10,9 @@
 target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024"
 target triple = "spir64-unknown-unknown"
 
-@.str.1 = private unnamed_addr addrspace(1) constant [7 x i8] c"file.h\00", section "llvm.metadata"
+@.str.1 = private unnamed_addr constant [7 x i8] c"file.h\00", section "llvm.metadata"
 ; {6442:"0,1"} = {CacheControlLoadINTEL_Token:"CacheLevel,CacheControl"} = L1 Cached
-@.str.cc = private unnamed_addr addrspace(1) constant [13 x i8] c"{6442:\220,1\22}\00", section "llvm.metadata"
+@.str.cc = private unnamed_addr constant [13 x i8] c"{6442:\220,1\22}\00", section "llvm.metadata"
 
 ; CHECK-SPIRV-DAG: Capability SubgroupBufferPrefetchINTEL
 ; CHECK-SPIRV-DAG: Capability CacheControlsINTEL
@@ -35,7 +35,7 @@ target triple = "spir64-unknown-unknown"
 
 define spir_kernel void @test(i8 addrspace(1)* %ptr, i32 %num_bytes) {
 entry:
-  %annotated = call i8 addrspace(1)* @llvm.ptr.annotation.p1i8(i8 addrspace(1)* %ptr, i8* getelementptr inbounds ([13 x i8], [13 x i8]* addrspacecast ([13 x i8] addrspace(1)* @.str.cc to [13 x i8]*), i64 0, i64 0), i8* getelementptr inbounds ([7 x i8], [7 x i8]* addrspacecast ([7 x i8] addrspace(1)* @.str.1 to [7 x i8]*), i64 0, i64 0), i32 0, i8* null)
+  %annotated = call i8 addrspace(1)* @llvm.ptr.annotation.p1i8(i8 addrspace(1)* %ptr, i8* getelementptr inbounds ([13 x i8], [13 x i8]* @.str.cc, i32 0, i32 0), i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.1, i32 0, i32 0), i32 0, i8* null)
   call spir_func void @_Z34__spirv_SubgroupBlockPrefetchINTELPU3AS1Khj(i8 addrspace(1)* %annotated, i32 %num_bytes)
   ret void
 }