Fix OCL builtins translation in case SPV_KHR_untyped_pointers is enabled (#2723)

This change allows to preserve the correct builtin mangling in reverse translation.

Original commit:
KhronosGroup/SPIRV-LLVM-Translator@33150bf7b08a0d4

Author: vmaksimo

llvm-spirv/lib/SPIRV/SPIRVReader.cpp

@@ -4878,6 +4878,18 @@ Instruction *SPIRVToLLVM::transOCLBuiltinFromExtInst(SPIRVExtInst *BC,
          "Not OpenCL extended instruction");
 
   std::vector<Type *> ArgTypes = transTypeVector(BC->getArgTypes(), true);
+  for (unsigned I = 0; I < ArgTypes.size(); I++) {
+    // Special handling for "truly" untyped pointers to preserve correct OCL
+    // bultin mangling.
+    if (isa<PointerType>(ArgTypes[I]) &&
+        BC->getArgValue(I)->isUntypedVariable()) {
+      auto *BVar = static_cast<SPIRVUntypedVariableKHR *>(BC->getArgValue(I));
+      ArgTypes[I] = TypedPointerType::get(
+          transType(BVar->getDataType()),
+          SPIRSPIRVAddrSpaceMap::rmap(BVar->getStorageClass()));
+    }
+  }
+
   Type *RetTy = transType(BC->getType());
   std::string MangledName =
       getSPIRVFriendlyIRFunctionName(ExtOp, ArgTypes, RetTy);

llvm-spirv/lib/SPIRV/libSPIRV/SPIRVEntry.h

@@ -342,6 +342,7 @@ class SPIRVEntry {
   bool isVariable() const {
     return OpCode == OpVariable || OpCode == OpUntypedVariableKHR;
   }
+  bool isUntypedVariable() const { return OpCode == OpUntypedVariableKHR; }
   bool isEndOfBlock() const;
   virtual bool isInst() const { return false; }
   virtual bool isOperandLiteral(unsigned Index) const {

llvm-spirv/lib/SPIRV/libSPIRV/SPIRVInstruction.h

@@ -1986,14 +1986,16 @@ class SPIRVExtInst : public SPIRVFunctionCallGeneric<OpExtInst, 5> {
   }
   std::vector<SPIRVValue *> getArgValues() {
     std::vector<SPIRVValue *> VArgs;
-    for (size_t I = 0; I < Args.size(); ++I) {
-      if (isOperandLiteral(I))
-        VArgs.push_back(Module->getLiteralAsConstant(Args[I]));
-      else
-        VArgs.push_back(getValue(Args[I]));
-    }
+    for (size_t I = 0; I < Args.size(); ++I)
+      VArgs.push_back(getArgValue(I));
     return VArgs;
   }
+  SPIRVValue *getArgValue(SPIRVWord I) {
+    if (isOperandLiteral(I))
+      return Module->getLiteralAsConstant(Args[I]);
+    return getValue(Args[I]);
+  }
+
   std::vector<SPIRVType *> getArgTypes() {
     std::vector<SPIRVType *> ArgTypes;
     auto VArgs = getArgValues();

llvm-spirv/test/transcoding/float16.ll

@@ -1,23 +1,34 @@
 ; RUN: llvm-as %s -o %t.bc
 ; RUN: llvm-spirv %t.bc -o %t.spv
 ; RUN: spirv-val %t.spv
-; RUN: llvm-spirv %t.spv -to-text -o - | FileCheck %s --check-prefix=CHECK-SPIRV
+; RUN: llvm-spirv %t.spv -to-text -o - | FileCheck %s --check-prefixes=CHECK-SPIRV,CHECK-SPIRV-NOEXT
+; RUN: llvm-spirv -r %t.spv -o %t.rev.bc
+; RUN: llvm-dis %t.rev.bc -o - | FileCheck %s --check-prefix=CHECK-LLVM
+
+; Verify that even though we use the fract instruction with untyped pointers enabled,
+; the SPV binary is valid and we get exactly the same output IR after the reverse translation.
+; RUN: llvm-spirv %t.bc -o %t.spv --spirv-ext=+SPV_KHR_untyped_pointers
+; TODO: enable back once spirv-tools are updated
+; R/UN: spirv-val %t.spv
+; RUN: llvm-spirv %t.spv -to-text -o - | FileCheck %s --check-prefixes=CHECK-SPIRV,CHECK-SPIRV-EXT
 ; RUN: llvm-spirv -r %t.spv -o %t.rev.bc
 ; RUN: llvm-dis %t.rev.bc -o - | FileCheck %s --check-prefix=CHECK-LLVM
 
 source_filename = "math_builtin_float_half.cpp"
 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 = "spirv64-unknown-unknown"
 
-; CHECK-SPIRV: 3 TypeFloat [[HALF:[0-9]+]] 16
-; CHECK-SPIRV: 4 TypePointer [[HALFPTR:[0-9]+]] 7 [[HALF]]
-; CHECK-SPIRV: 4 TypeVector [[HALFV2:[0-9]+]] [[HALF]] 2
-; CHECK-SPIRV: 4 TypePointer [[HALFV2PTR:[0-9]+]] 7 [[HALFV2]]
-; CHECK-SPIRV: 4 Constant [[HALF]] [[CONST:[0-9]+]] 14788
-; CHECK-SPIRV: 4 Variable [[HALFPTR]] [[ADDR:[0-9]+]] 7
-; CHECK-SPIRV: 4 Variable [[HALFV2PTR]] [[ADDR2:[0-9]+]] 7
-; CHECK-SPIRV: 7 ExtInst [[HALF]] [[#]] 1 fract [[CONST]] [[ADDR]]
-; CHECK-SPIRV: 7 ExtInst [[HALFV2]] [[#]] 1 fract [[#]] [[ADDR2]]
+; CHECK-SPIRV: TypeFloat [[HALF:[0-9]+]] 16
+; CHECK-SPIRV-NOEXT: TypePointer [[HALFPTR:[0-9]+]] 7 [[HALF]]
+; CHECK-SPIRV-EXT: TypeUntypedPointerKHR [[HALFPTR:[0-9]+]] 7
+; CHECK-SPIRV: TypeVector [[HALFV2:[0-9]+]] [[HALF]] 2
+; CHECK-SPIRV: TypePointer [[HALFV2PTR:[0-9]+]] 7 [[HALFV2]]
+; CHECK-SPIRV: Constant [[HALF]] [[CONST:[0-9]+]] 14788
+; CHECK-SPIRV-NOEXT: Variable [[HALFPTR]] [[ADDR:[0-9]+]] 7
+; CHECK-SPIRV-EXT: UntypedVariableKHR [[HALFPTR]] [[ADDR:[0-9]+]] 7 [[HALF]]
+; CHECK-SPIRV: Variable [[HALFV2PTR]] [[ADDR2:[0-9]+]] 7
+; CHECK-SPIRV: ExtInst [[HALF]] [[#]] 1 fract [[CONST]] [[ADDR]]
+; CHECK-SPIRV: ExtInst [[HALFV2]] [[#]] 1 fract [[#]] [[ADDR2]]
 
 ; CHECK-LLVM: %addr = alloca half
 ; CHECK-LLVM: %addr2 = alloca <2 x half>