Support atomic intrinsics for Metal (shader-slang#4473)

* Support atomic intrinsics for Metal

This commit adds a support for the atomic intrinsics in Metal.
The atomic member functions for buffers is not implemented yet.

Metal requires the first argument for the atomic functions to be an
atomic data type. This implementation rely on the fact that we can do a
C-style type casting from a regular data type to an atomic data type.

Author: jkwak-work

source/slang/hlsl.meta.slang

@@ -2889,6 +2889,7 @@ void CLikeSourceEmitter::_emitInst(IRInst* inst)
     case kIROp_AtomicCounterIncrement:
     case kIROp_AtomicCounterDecrement:
     case kIROp_StructuredBufferGetDimensions:
+    case kIROp_MetalAtomicCast:
         emitInstStmt(inst);
         break;
 

source/slang/slang-emit-c-like.cpp

@@ -253,6 +253,24 @@ bool MetalSourceEmitter::tryEmitInstStmtImpl(IRInst* inst)
     case kIROp_discard:
         m_writer->emit("discard_fragment();\n");
         return true;
+    case kIROp_MetalAtomicCast:
+    {
+        auto oldValName = getName(inst);
+        auto op0 = inst->getOperand(0);
+
+        m_writer->emit("atomic_");
+        emitType(op0->getDataType());
+        m_writer->emit(" ");
+        m_writer->emit(oldValName);
+        m_writer->emit(" = ");
+
+        m_writer->emit("((atomic_");
+        emitType(op0->getDataType());
+        m_writer->emit(")(");
+        emitOperand(op0, getInfo(EmitOp::General));
+        m_writer->emit("));\n");
+        return true;
+    }
     }
     return false;
 }

source/slang/slang-emit-metal.cpp

@@ -685,6 +685,7 @@ INST(GetLegalizedSPIRVGlobalParamAddr, GetLegalizedSPIRVGlobalParamAddr, 1, 0)
 INST(GetPerVertexInputArray, GetPerVertexInputArray, 1, 0)
 
 INST(ForceVarIntoStructTemporarily, ForceVarIntoStructTemporarily, 1, 0)
+INST(MetalAtomicCast, MetalAtomicCast, 1, 0)
 
 INST(MakeArrayList, makeArrayList, 0, 0)
 INST(MakeTensorView, makeTensorView, 0, 0)

source/slang/slang-ir-inst-defs.h

@@ -1,6 +1,6 @@
 //TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -shaderobj 
 //TEST(compute,vulkan):COMPARE_COMPUTE_EX:-vk -slang -compute -shaderobj
-//DISABLE_TEST(compute):COMPARE_COMPUTE:-slang -shaderobj -mtl
+//TEST(compute):COMPARE_COMPUTE:-slang -shaderobj -mtl
 
 //TEST_INPUT:ubuffer(data=[0 0 0 0 ], stride=4):out,name outputBuffer
 RWStructuredBuffer<int> outputBuffer;

tests/bugs/atomic-coerce.slang

@@ -4,7 +4,7 @@
 //TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -dx12 -shaderobj
 //TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -vk -shaderobj
 //TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -cuda -shaderobj
-//DISABLE_TEST(compute):COMPARE_COMPUTE:-slang -shaderobj -mtl
+//TEST(compute):COMPARE_COMPUTE:-slang -shaderobj -mtl
 
 //TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out,name outputBuffer
 

tests/compute/atomics-groupshared.slang

@@ -4,7 +4,7 @@
 //TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -dx12 -shaderobj
 //TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -vk -shaderobj
 //TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -cuda -shaderobj
-//DISABLE_TEST(compute):COMPARE_COMPUTE:-slang -shaderobj -mtl
+//TEST(compute):COMPARE_COMPUTE:-slang -shaderobj -mtl
 
 //TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out, name outputBuffer