[Backport to 15] Fix BFloat16 argument type demangling (#3563)

This also includes patrial cherry-pick of fd1ed03 "Workaround for `bfloat16` parameter type demangling"

Author: vmaksimo

lib/SPIRV/SPIRVUtil.cpp

@@ -813,15 +813,34 @@ void getParameterTypes(Function *F, SmallVectorImpl<StructType *> &ArgTys) {
   if (HasSret)
     ++ArgIter;
 
+  // "DF<N>b" mangling for bfloat<N> types (e.g. DF16b for bfloat16) is
+  // recognized by the demangler only starting from LLVM 20. Replace "DF16b"
+  // in the parameter section with the vendor-extended-type encoding "u6__bf16",
+  // which all known demangler versions parse correctly as NameType("__bf16").
+  std::string PatchedName;
+  StringRef MangledName(F->getName());
+  if (MangledName.contains("DF16b")) {
+    PatchedName = MangledName.str();
+    // Skip "_Z<N><name>" to search only in the parameter section.
+    const size_t Start = PatchedName.find_first_not_of("0123456789", 2);
+    size_t Len = 0;
+    StringRef(PatchedName).substr(2, Start - 2).getAsInteger(10, Len);
+    size_t Pos = Start + Len;
+    while ((Pos = PatchedName.find("DF16b", Pos)) != std::string::npos) {
+      PatchedName.replace(Pos, 5, "u6__bf16");
+      Pos += 8;
+    }
+    MangledName = PatchedName;
+  }
+
   // Demangle the function arguments. If we get an input name of
   // "_Z12write_imagei20ocl_image1d_array_woDv2_iiDv4_i", then we expect
   // that Demangler.getFunctionParameters will return
   // "(ocl_image1d_array_wo, int __vector(2), int, int __vector(4))" (in other
   // words, the stuff between the parentheses if you ran C++ filt, including
   // the parentheses itself).
   ItaniumPartialDemangler Demangler;
-  std::string MangledName = F->getName().str();
-  if (Demangler.partialDemangle(MangledName.c_str()))
+  if (Demangler.partialDemangle(MangledName.data()))
     return;
   char *Buf = nullptr;
   size_t BufLen = 0;
@@ -865,6 +884,8 @@ void getParameterTypes(Function *F, SmallVectorImpl<StructType *> &ArgTys) {
           Pointee = getOrCreateOpaqueStructType(M, StructName);
         } else if (MangledStructName.startswith("opencl.")) {
           Pointee = getOrCreateOpaqueStructType(M, MangledStructName);
+        } else if (MangledStructName == "__bf16") {
+          Pointee = Type::getBFloatTy(M->getContext());
         }
       } else if (!Arg.contains(' ') && Arg.startswith("ocl_")) {
         std::string StructName = demangleBuiltinOpenCLTypeName(Arg);

…NTEL/SPV_INTEL_bfloat16/bfloat16_math.ll …TEL_bfloat16_arithmetic/bfloat16_math.lltest/extensions/INTEL/SPV_INTEL_bfloat16/bfloat16_math.ll renamed to test/extensions/INTEL/SPV_INTEL_bfloat16_arithmetic/bfloat16_math.ll test/extensions/INTEL/SPV_INTEL_bfloat16/bfloat16_math.ll renamed to test/extensions/INTEL/SPV_INTEL_bfloat16_arithmetic/bfloat16_math.ll

@@ -0,0 +1,61 @@
+; RUN: llvm-as %s -o %t.bc
+; RUN: llvm-spirv %t.bc -spirv-text -o %t.spt --spirv-ext=+SPV_KHR_bfloat16,+SPV_INTEL_bfloat16_arithmetic
+; RUN: FileCheck < %t.spt %s --check-prefix=CHECK-SPIRV
+; RUN: llvm-spirv -to-binary %t.spt -o %t.spv
+; TODO: reenable the validation once the BFloat16 type is supported in ExtInst.
+; Currently fails with: ExtInst doesn't support BFloat16 type.
+; RUNx: spirv-val %t.spv
+; RUN: llvm-spirv -r %t.spv -o - | llvm-dis -o %t.rev.ll
+; RUN: FileCheck < %t.rev.ll %s --check-prefix=CHECK-LLVM
+; RUN: llvm-spirv -r %t.spv --spirv-target-env=SPV-IR -o - | llvm-dis -o %t.rev.ll
+; RUN: FileCheck < %t.rev.ll %s --check-prefix=CHECK-SPV-IR
+
+
+; CHECK-SPIRV: Capability BFloat16TypeKHR
+; CHECK-SPIRV: Extension "SPV_KHR_bfloat16"
+; CHECK-SPIRV: TypeFloat [[#BFLOAT:]] 16 0
+; CHECK-SPIRV: TypeVector [[#VEC:]] [[#BFLOAT]] 2
+; CHECK-SPIRV: TypePointer [[#PTR:]] [[#]] [[#BFLOAT]]
+
+; CHECK-LABEL: Function
+; CHECK-SPIRV: FunctionParameter [[#PTR]] [[#PTR_ARG:]]
+; CHECK-SPIRV: ExtInst [[#VEC]] [[#]] [[#]] vloadn [[#]] [[#PTR_ARG]] 2
+
+; CHECK-LABEL: Function
+; CHECK-SPIRV: FunctionParameter [[#VEC]] [[#DATA_ARG:]]
+; CHECK-SPIRV: FunctionParameter [[#PTR]] [[#PTR_ARG2:]]
+; CHECK-SPIRV: ExtInst [[#]] [[#]] [[#]] vstoren [[#DATA_ARG]] [[#]] [[#PTR_ARG2]]
+
+target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-n8:16:32:64"
+target triple = "spir64-unknown-unknown"
+
+; CHECK-LLVM: call spir_func <2 x bfloat> @_Z6vload2mPU3AS1KDF16b(i64 %offset, bfloat addrspace(1)* %ptr)
+; CHECK-LLVM: call spir_func void @_Z7vstore2Dv2_DF16bmPU3AS1DF16b(<2 x bfloat> %data, i64 %offset, bfloat addrspace(1)* %ptr)
+
+; CHECK-SPV-IR: call spir_func <2 x bfloat> @_Z26__spirv_ocl_vloadn_RDF16b2mPU3AS1KDF16bi(i64 %offset, bfloat addrspace(1)* %ptr, i32 2)
+; CHECK-SPV-IR: call spir_func void @_Z19__spirv_ocl_vstorenDv2_DF16bmPU3AS1DF16b(<2 x bfloat> %data, i64 %offset, bfloat addrspace(1)* %ptr)
+
+define spir_func <2 x bfloat> @test_spirv_ocl_vload2(i64 %offset, ptr addrspace(1) %ptr) {
+  %result = call spir_func <2 x bfloat> @_Z26__spirv_ocl_vloadn__RDF16blPU3AS1DF16bi(i64 %offset, bfloat addrspace(1)* %ptr, i32 2)
+  ret <2 x bfloat> %result
+}
+
+define spir_func void @test_spirv_ocl_vstore2(<2 x bfloat> %data, i64 %offset, ptr addrspace(1) %ptr) {
+  call spir_func void @_Z19__spirv_ocl_vstorenDv2_DF16blPU3AS1DF16b(<2 x bfloat> %data, i64 %offset, bfloat addrspace(1)* %ptr)
+  ret void
+}
+
+declare spir_func <2 x bfloat> @_Z26__spirv_ocl_vloadn__RDF16blPU3AS1DF16bi(i64, bfloat addrspace(1)*, i32)
+declare spir_func void @_Z19__spirv_ocl_vstorenDv2_DF16blPU3AS1DF16b(<2 x bfloat>, i64, bfloat addrspace(1)*)
+
+!opencl.enable.FP_CONTRACT = !{}
+!opencl.spir.version = !{!0}
+!opencl.ocl.version = !{!1}
+!opencl.used.extensions = !{!2}
+!opencl.used.optional.core.features = !{!3}
+!opencl.compiler.options = !{!3}
+
+!0 = !{i32 1, i32 2}
+!1 = !{i32 2, i32 0}
+!2 = !{!"cl_khr_fp16"}
+!3 = !{}