Add support for ulonglong and longlong types in const values handle (#7957)

referencing
#7952 for
details

---------

Co-authored-by: Przemog1 <[email protected]>

Author: AnastaZIuk

docs/ReleaseNotes.md

@@ -23,6 +23,7 @@ The included licenses apply to the following files:
 - Fixed regression: [#7508](https://github.com/microsoft/DirectXShaderCompiler/issues/7508) crash when calling `Load` with `status`.
 - Header file `dxcpix.h` was added to the release package.
 - Moved Linear Algebra (Cooperative Vector) DXIL Opcodes to experimental Shader Model 6.10
+- Added support for `long long` and `unsigned long long` compile-time constant evaluation, fixes [#7952](https://github.com/microsoft/DirectXShaderCompiler/issues/7952).
 
 ### Version 1.8.2505
 

tools/clang/lib/SPIRV/DeclResultIdMapper.cpp

@@ -4920,12 +4920,19 @@ bool DeclResultIdMapper::tryToCreateConstantVar(const ValueDecl *decl) {
     constVal =
         spvBuilder.getConstantInt(astContext.UnsignedIntTy, val->getInt());
     break;
+  case BuiltinType::ULongLong: // uint64_t
+    constVal =
+        spvBuilder.getConstantInt(astContext.UnsignedLongLongTy, val->getInt());
+    break;
   case BuiltinType::Short: // int16_t
     constVal = spvBuilder.getConstantInt(astContext.ShortTy, val->getInt());
     break;
   case BuiltinType::Int: // int32_t
     constVal = spvBuilder.getConstantInt(astContext.IntTy, val->getInt());
     break;
+  case BuiltinType::LongLong: // int64_t
+    constVal = spvBuilder.getConstantInt(astContext.LongLongTy, val->getInt());
+    break;
   case BuiltinType::Half: // float16_t
     constVal = spvBuilder.getConstantFloat(astContext.HalfTy, val->getFloat());
     break;

tools/clang/test/CodeGenSPIRV/spv.constant-folding.template.int64.hlsl

@@ -0,0 +1,24 @@
+// RUN: %dxc %s -T lib_6_8 -E main -spirv -enable-16bit-types
+
+// CHECK-DAG: %ulong = OpTypeInt 64 0
+// CHECK-DAG:  %long = OpTypeInt 64 1
+
+template <typename T> struct S {
+  static const T value = 0;
+};
+
+// CHECK: %u = OpFunction %void None
+[shader("vertex")]
+uint64_t u() : A
+{
+  // CHECK: OpStore %out_var_A %ulong_0
+  return S<uint64_t>::value;
+}
+
+// CHECK: %s = OpFunction %void None
+[shader("vertex")]
+int64_t s() : B
+{
+  // CHECK: OpStore %out_var_A %long_0
+  return S<int64_t>::value;
+}