SPV_KHR_untyped_pointers - fix images translation (#2817)

This patch ensures that we are loading image type, not untyped pointer
type when the extension is used. This way we also preserve correct
mangling during the reverse translation.

Original commit:
KhronosGroup/SPIRV-LLVM-Translator@cd7985fb6d2589d

Author: vmaksimo

llvm-spirv/lib/SPIRV/SPIRVWriter.cpp

@@ -2226,13 +2226,19 @@ LLVMToSPIRVBase::transValueWithoutDecoration(Value *V, SPIRVBasicBlock *BB,
                              MemoryAccessNoAliasINTELMaskMask);
     if (MemoryAccess.front() == 0)
       MemoryAccess.clear();
-    return mapValue(
-        V,
-        BM->addLoadInst(
-            transValue(LD->getPointerOperand(), BB), MemoryAccess, BB,
-            BM->isAllowedToUseExtension(ExtensionID::SPV_KHR_untyped_pointers)
-                ? transType(LD->getType())
-                : nullptr));
+    if (BM->isAllowedToUseExtension(ExtensionID::SPV_KHR_untyped_pointers)) {
+      SPIRVValue *Source = transValue(LD->getPointerOperand(), BB);
+      SPIRVType *LoadTy = transType(LD->getType());
+      // For images do not use explicit load type, but rather use the source
+      // type (calculated in SPIRVLoad constructor)
+      if (LoadTy->isTypeUntypedPointerKHR() &&
+          (Source->getType()->getPointerElementType()->isTypeImage())) {
+        LoadTy = nullptr;
+      }
+      return mapValue(V, BM->addLoadInst(Source, MemoryAccess, BB, LoadTy));
+    }
+    return mapValue(V, BM->addLoadInst(transValue(LD->getPointerOperand(), BB),
+                                       MemoryAccess, BB));
   }
 
   if (BinaryOperator *B = dyn_cast<BinaryOperator>(V)) {

llvm-spirv/test/transcoding/get_image_num_mip_levels.ll

@@ -8,6 +8,15 @@
 ; RUN: llvm-dis < %t.rev.bc | FileCheck %s --check-prefix=CHECK-SPV-IR
 ; RUN: llvm-spirv -spirv-text %t.rev.bc -o - | FileCheck %s --check-prefix=CHECK-SPIRV
 
+; RUN: llvm-spirv --spirv-ext=+SPV_KHR_untyped_pointers -spirv-text %t.bc -o - | FileCheck %s --check-prefix=CHECK-SPIRV
+; RUN: llvm-spirv --spirv-ext=+SPV_KHR_untyped_pointers %t.bc -o %t.spv
+; RUN: spirv-val %t.spv
+; RUN: llvm-spirv -r %t.spv -o %t.rev.bc
+; RUN: llvm-dis < %t.rev.bc | FileCheck %s --check-prefix=CHECK-LLVM
+; RUN: llvm-spirv -r %t.spv -o %t.rev.bc --spirv-target-env=SPV-IR
+; RUN: llvm-dis < %t.rev.bc | FileCheck %s --check-prefix=CHECK-SPV-IR
+; RUN: llvm-spirv -spirv-text %t.rev.bc -o - | FileCheck %s --check-prefix=CHECK-SPIRV
+
 ; Generated from the following OpenCL C code:
 ; #pragma OPENCL EXTENSION cl_khr_mipmap_image : enable
 ; void test(image1d_t img1, 

llvm-spirv/test/transcoding/image_with_access_qualifiers.ll

@@ -5,6 +5,12 @@
 ; RUN: llvm-spirv -r %t.spv -o %t.rev.bc
 ; RUN: llvm-dis < %t.rev.bc | FileCheck %s --check-prefix=CHECK-LLVM
 
+; RUN: llvm-spirv --spirv-ext=+SPV_KHR_untyped_pointers %t.bc -spirv-text -o %t.txt
+; RUN: FileCheck < %t.txt %s --check-prefix=CHECK-SPIRV
+; RUN: llvm-spirv --spirv-ext=+SPV_KHR_untyped_pointers %t.bc -o %t.spv
+; RUN: llvm-spirv -r %t.spv -o %t.rev.bc
+; RUN: llvm-dis < %t.rev.bc | FileCheck %s --check-prefix=CHECK-LLVM
+
 ; NOTE: access qualifier infomation is not preserved after round-trip conversion to LLVM
 ; CHECK-LLVM: call spir_func <4 x float> @_Z11read_imagef14ocl_image1d_rw11ocl_sampleri(ptr