reinterpret and 16-bit value packing. (shader-slang#1933)

* `reinterpret` and 16-bit value packing.

* Update `half-texture` cross-compile test reference result.

* Revert inadvertent reformatting of slang-ir-inst-defs.h

Co-authored-by: Yong He <yhe@nvidia.com>

Author: csyonghe

build/visual-studio/slang/slang.vcxproj

@@ -251,6 +251,7 @@
     <ClInclude Include="..\..\..\source\slang\slang-ir-lower-generic-function.h" />
     <ClInclude Include="..\..\..\source\slang\slang-ir-lower-generic-type.h" />
     <ClInclude Include="..\..\..\source\slang\slang-ir-lower-generics.h" />
+    <ClInclude Include="..\..\..\source\slang\slang-ir-lower-reinterpret.h" />
     <ClInclude Include="..\..\..\source\slang\slang-ir-lower-tuple-types.h" />
     <ClInclude Include="..\..\..\source\slang\slang-ir-missing-return.h" />
     <ClInclude Include="..\..\..\source\slang\slang-ir-optix-entry-point-uniforms.h" />
@@ -380,6 +381,7 @@
     <ClCompile Include="..\..\..\source\slang\slang-ir-lower-generic-function.cpp" />
     <ClCompile Include="..\..\..\source\slang\slang-ir-lower-generic-type.cpp" />
     <ClCompile Include="..\..\..\source\slang\slang-ir-lower-generics.cpp" />
+    <ClCompile Include="..\..\..\source\slang\slang-ir-lower-reinterpret.cpp" />
     <ClCompile Include="..\..\..\source\slang\slang-ir-lower-tuple-types.cpp" />
     <ClCompile Include="..\..\..\source\slang\slang-ir-missing-return.cpp" />
     <ClCompile Include="..\..\..\source\slang\slang-ir-optix-entry-point-uniforms.cpp" />

build/visual-studio/slang/slang.vcxproj.filters

@@ -204,6 +204,9 @@
     <ClInclude Include="..\..\..\source\slang\slang-ir-lower-generics.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="..\..\..\source\slang\slang-ir-lower-reinterpret.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
     <ClInclude Include="..\..\..\source\slang\slang-ir-lower-tuple-types.h">
       <Filter>Header Files</Filter>
     </ClInclude>
@@ -587,6 +590,9 @@
     <ClCompile Include="..\..\..\source\slang\slang-ir-lower-generics.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\..\source\slang\slang-ir-lower-reinterpret.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
     <ClCompile Include="..\..\..\source\slang\slang-ir-lower-tuple-types.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>

source/slang/core.meta.slang

@@ -1907,6 +1907,12 @@ __generic<T, U>
 __intrinsic_op($(kIROp_CreateExistentialObject))
 T createDynamicObject(uint typeId, U value);
 
+// Reinterpret
+__generic<T, U>
+[__unsafeForceInlineEarly]
+__intrinsic_op($(kIROp_Reinterpret))
+T reinterpret(U value);
+
 // Specialized function
 
 /// Given a string returns an integer hash of that string.

source/slang/slang-diagnostic-defs.h

@@ -503,6 +503,9 @@ DIAGNOSTIC(41000, Warning, unreachableCode, "unreachable code detected")
 DIAGNOSTIC(41010, Warning, missingReturn, "control flow may reach end of non-'void' function")
 
 DIAGNOSTIC(41011, Error, typeDoesNotFitAnyValueSize, "type '$0' does not fit in the size required by its conforming interface.")
+
+DIAGNOSTIC(41012, Error, typeCannotBePackedIntoAnyValue, "type '$0' contains fields that cannot be packed into an AnyValue.")
+
 //
 // 5xxxx - Target code generation.
 //

source/slang/slang-emit-hlsl.cpp

@@ -479,7 +479,9 @@ bool HLSLSourceEmitter::tryEmitInstExprImpl(IRInst* inst, const EmitOpInfo& inOu
                     emitType(inst->getDataType());
                     m_writer->emit(")");
                     break;
-
+                case BaseType::Half:
+                    m_writer->emit("f16tof32");
+                    break;
                 case BaseType::Float:
                     // Note: at present HLSL only supports
                     // reinterpreting integer bits as a `float`.
@@ -511,11 +513,18 @@ bool HLSLSourceEmitter::tryEmitInstExprImpl(IRInst* inst, const EmitOpInfo& inOu
                 case BaseType::UInt:
                 case BaseType::Int:
                     break;
-
+                case BaseType::UInt16:
+                case BaseType::Int16:
+                    break;
                 case BaseType::Float:
                     m_writer->emit("asuint(");
                     closeCount++;
                     break;
+
+                case BaseType::Half:
+                    m_writer->emit("f32tof16(");
+                    closeCount++;
+                    break;
             }
 
             emitOperand(inst->getOperand(0), getInfo(EmitOp::General));
@@ -750,20 +759,32 @@ void HLSLSourceEmitter::emitSimpleTypeImpl(IRType* type)
         case kIROp_VoidType:
         case kIROp_BoolType:
         case kIROp_Int8Type:
-        case kIROp_Int16Type:
         case kIROp_IntType:
         case kIROp_Int64Type:
         case kIROp_UInt8Type:
-        case kIROp_UInt16Type:
         case kIROp_UIntType:
         case kIROp_UInt64Type:
         case kIROp_FloatType:
         case kIROp_DoubleType:
-        case kIROp_HalfType:
         {
             m_writer->emit(getDefaultBuiltinTypeName(type->getOp()));
             return;
         }
+        case kIROp_Int16Type:
+        {
+            m_writer->emit("min16int");
+            return;
+        }
+        case kIROp_UInt16Type:
+        {
+            m_writer->emit("min16uint");
+            return;
+        }
+        case kIROp_HalfType:
+        {
+            m_writer->emit("min16float");
+            return;
+        }
         case kIROp_StructType:
             m_writer->emit(getName(type));
             return;

source/slang/slang-emit.cpp

@@ -21,6 +21,7 @@
 #include "slang-ir-lower-generics.h"
 #include "slang-ir-lower-tuple-types.h"
 #include "slang-ir-lower-bit-cast.h"
+#include "slang-ir-lower-reinterpret.h"
 #include "slang-ir-optix-entry-point-uniforms.h"
 #include "slang-ir-restructure.h"
 #include "slang-ir-restructure-scoping.h"
@@ -327,6 +328,8 @@ Result linkAndOptimizeIR(
 
     eliminateDeadCode(irModule);
 
+    lowerReinterpret(targetRequest, irModule, sink);
+
     // For targets that supports dynamic dispatch, we need to lower the
     // generics / interface types to ordinary functions and types using
     // function pointers.