Support function pointers in cast instructions

Author: zuban32

lib/SPIRV/SPIRVWriter.cpp

@@ -696,6 +696,7 @@ SPIRVInstruction *LLVMToSPIRV::transCmpInst(CmpInst *Cmp, SPIRVBasicBlock *BB) {
 SPIRV::SPIRVInstruction *LLVMToSPIRV::transUnaryInst(UnaryInstruction *U,
                                                      SPIRVBasicBlock *BB) {
   Op BOC = OpNop;
+  SPIRVValue *Op = nullptr;
   if (auto Cast = dyn_cast<AddrSpaceCastInst>(U)) {
     if (Cast->getDestTy()->getPointerAddressSpace() == SPIRAS_Generic) {
       assert(Cast->getSrcTy()->getPointerAddressSpace() != SPIRAS_Constant &&
@@ -710,9 +711,21 @@ SPIRV::SPIRVInstruction *LLVMToSPIRV::transUnaryInst(UnaryInstruction *U,
   } else {
     auto OpCode = U->getOpcode();
     BOC = OpCodeMap::map(OpCode);
+
+    if (Function *F = dyn_cast<Function>(U->getOperand(0))) {
+      if (!BM->checkExtension(ExtensionID::SPV_INTEL_function_pointers,
+                              SPIRVEC_FunctionPointers, toString(U)))
+        return nullptr;
+      assert(BOC == OpConvertPtrToU &&
+             "Illegal unary operation on function pointer");
+      Op = BM->addFunctionPointerINTELInst(
+          transType(F->getType()),
+          static_cast<SPIRVFunction *>(transValue(F, BB)), BB);
+    }
   }
 
-  auto Op = transValue(U->getOperand(0), BB);
+  if (!Op)
+    Op = transValue(U->getOperand(0), BB);
   return BM->addUnaryInst(transBoolOpCode(Op, BOC), transType(U->getType()), Op,
                           BB);
 }

test/constexpr_vector.ll

@@ -43,9 +43,11 @@
 ; CHECK-LLVM-NEXT:   ret void
 ; CHECK-LLVM-NEXT: }
 
-; RUN: llvm-as < %s | llvm-spirv -spirv-text | FileCheck %s --check-prefix=CHECK-SPIRV
+; RUN: llvm-as < %s | llvm-spirv -spirv-text --spirv-ext=+SPV_INTEL_function_pointers | FileCheck %s --check-prefix=CHECK-SPIRV
 
-; CHECK-SPIRV: 4 Name [[Funcs:[0-9]+]] "Funcs"
+; CHECK-SPIRV-DAG: 4 Name [[Funcs:[0-9]+]] "Funcs"
+; CHECK-SPIRV-DAG: 6 Name [[F1:[0-9+]]] "_Z2f1u2CMvb32_j"
+; CHECK-SPIRV-DAG: 6 Name [[F2:[0-9+]]] "_Z2f2u2CMvb32_j"
 
 ; CHECK-SPIRV-DAG: 4 TypeInt [[TypeInt8:[0-9]+]] 8 0
 ; CHECK-SPIRV-DAG: 4 TypeInt [[TypeInt32:[0-9]+]] 32 0
@@ -55,7 +57,8 @@
 ; CHECK-SPIRV-DAG: 4 TypePointer [[StorePtr:[0-9]+]] 7 [[TypeVec16]]
 ; CHECK-SPIRV-DAG: 3 Undef [[TypeVec16]] [[TypeUndef:[0-9]+]]
 
-; CHECK-SPIRV: 4 ConvertPtrToU [[TypeInt64]] [[Ptr1:[0-9]+]] {{[0-9]+}}
+; CHECK-SPIRV: 4 FunctionPointerINTEL [[FuncPtrTy:[0-9]+]] [[F1Ptr:[0-9]+]] [[F1]]
+; CHECK-SPIRV-NEXT: 4 ConvertPtrToU [[TypeInt64]] [[Ptr1:[0-9]+]] [[F1Ptr]]
 ; CHECK-SPIRV-NEXT: 4 Bitcast [[TypeVec8]] [[Vec1:[0-9]+]] [[Ptr1]]
 ; CHECK-SPIRV-NEXT: 5 CompositeExtract [[TypeInt8]] [[v00:[0-9]+]] [[Vec1]] 0
 ; CHECK-SPIRV-NEXT: 5 CompositeExtract [[TypeInt8]] [[v01:[0-9]+]] [[Vec1]] 1
@@ -65,7 +68,8 @@
 ; CHECK-SPIRV-NEXT: 5 CompositeExtract [[TypeInt8]] [[v05:[0-9]+]] [[Vec1]] 5
 ; CHECK-SPIRV-NEXT: 5 CompositeExtract [[TypeInt8]] [[v06:[0-9]+]] [[Vec1]] 6
 ; CHECK-SPIRV-NEXT: 5 CompositeExtract [[TypeInt8]] [[v07:[0-9]+]] [[Vec1]] 7
-; CHECK-SPIRV-NEXT: 4 ConvertPtrToU [[TypeInt64]] [[Ptr2:[0-9]+]] {{[0-9]+}}
+; CHECK-SPIRV-NEXT: 4 FunctionPointerINTEL [[FuncPtrTy]] [[F2Ptr:[0-9]+]] [[F2]]
+; CHECK-SPIRV-NEXT: 4 ConvertPtrToU [[TypeInt64]] [[Ptr2:[0-9]+]] [[F2Ptr]]
 ; CHECK-SPIRV-NEXT: 4 Bitcast [[TypeVec8]] [[Vec2:[0-9]+]] [[Ptr2]]
 ; CHECK-SPIRV-NEXT: 5 CompositeExtract [[TypeInt8]] [[v10:[0-9]+]] [[Vec2]] 0
 ; CHECK-SPIRV-NEXT: 5 CompositeExtract [[TypeInt8]] [[v11:[0-9]+]] [[Vec2]] 1