[SPIRV] Add SM6.6 IsHelperLane (microsoft#5488)

Fix microsoft#5427

Author: jeremy-lunarg

tools/clang/include/clang/SPIRV/FeatureManager.h

@@ -89,7 +89,7 @@ class FeatureManager {
   std::string getKnownExtensions(const char *delimiter, const char *prefix = "",
                                  const char *postfix = "");
 
-  /// Rqeusts the given target environment for translating the given feature at
+  /// Request the given target environment for translating the given feature at
   /// the given source location. Emits an error if the requested target
   /// environment does not match user's target environemnt.
   bool requestTargetEnv(spv_target_env, llvm::StringRef target, SourceLocation);

tools/clang/lib/SPIRV/DeclResultIdMapper.cpp

@@ -3312,6 +3312,7 @@ SpirvVariable *DeclResultIdMapper::getBuiltinVar(spv::BuiltIn builtIn,
   spv::StorageClass sc = spv::StorageClass::Max;
   // Valid builtins supported
   switch (builtIn) {
+  case spv::BuiltIn::HelperInvocation:
   case spv::BuiltIn::SubgroupSize:
   case spv::BuiltIn::SubgroupLocalInvocationId:
     needsLegalization = true;

tools/clang/lib/SPIRV/SpirvEmitter.cpp

@@ -8504,6 +8504,9 @@ SpirvEmitter::processIntrinsicCallExpr(const CallExpr *callExpr) {
     retVal = spvBuilder.createLoad(retType, var, srcLoc, srcRange);
     needsLegalization = true;
   } break;
+  case hlsl::IntrinsicOp::IOP_IsHelperLane:
+    retVal = processIsHelperLane(callExpr, srcLoc, srcRange);
+    break;
   case hlsl::IntrinsicOp::IOP_WaveIsFirstLane:
     retVal = processWaveQuery(callExpr, spv::Op::OpGroupNonUniformElect);
     break;
@@ -9161,6 +9164,32 @@ SpirvInstruction *SpirvEmitter::processWaveQuery(const CallExpr *callExpr,
       opcode, retType, spv::Scope::Subgroup, callExpr->getExprLoc());
 }
 
+SpirvInstruction *SpirvEmitter::processIsHelperLane(const CallExpr *callExpr,
+                                                    SourceLocation loc,
+                                                    SourceRange range) {
+  assert(callExpr->getNumArgs() == 0);
+
+  if(!featureManager.isTargetEnvVulkan1p3OrAbove()) {
+    // If IsHelperlane is used for Vulkan 1.2 or less, we enable
+    // SPV_EXT_demote_to_helper_invocation extension to use
+    // OpIsHelperInvocationEXT instruction.
+    featureManager.allowExtension("SPV_EXT_demote_to_helper_invocation");
+
+    const QualType retType = callExpr->getCallReturnType(astContext);
+    return spvBuilder.createIsHelperInvocationEXT(retType, callExpr->getExprLoc());
+  }
+
+  // The SpreadVolatileSemanticsPass legalization pass will decorate the
+  // load with Volatile.
+  const QualType retType = callExpr->getCallReturnType(astContext);
+  auto *var =
+    declIdMapper.getBuiltinVar(spv::BuiltIn::HelperInvocation, retType, loc);
+  auto retVal = spvBuilder.createLoad(retType, var, loc, range);
+  needsLegalization = true;
+
+  return retVal;
+}
+
 SpirvInstruction *SpirvEmitter::processWaveVote(const CallExpr *callExpr,
                                                 spv::Op opcode) {
   // Signatures:

tools/clang/lib/SPIRV/SpirvEmitter.h

@@ -590,6 +590,10 @@ class SpirvEmitter : public ASTConsumer {
   /// Processes SM6.0 wave query intrinsic calls.
   SpirvInstruction *processWaveQuery(const CallExpr *, spv::Op opcode);
 
+  /// Processes SM6.6 IsHelperLane intrisic calls.
+  SpirvInstruction *processIsHelperLane(const CallExpr *, SourceLocation loc,
+                                        SourceRange range);
+
   /// Processes SM6.0 wave vote intrinsic calls.
   SpirvInstruction *processWaveVote(const CallExpr *, spv::Op opcode);
 

tools/clang/test/CodeGenSPIRV/intrinsics.sm6_6.ishelperlane.hlsl

@@ -0,0 +1,13 @@
+// RUN: %dxc -T ps_6_0 -E main
+
+// CHECK-NOT: OpDecorate {{%\w+}} BuiltIn HelperInvocation
+
+float4 main() : SV_Target {
+    float ret = 1.0;
+
+    if (IsHelperLane()) ret = 2.0;
+
+    return ret;
+}
+// CHECK: [[HelperInvocation:%\d+]] = OpIsHelperInvocationEXT %bool
+// CHECK: OpBranchConditional [[HelperInvocation]]

tools/clang/test/CodeGenSPIRV/intrinsics.sm6_6.ishelperlane.vk1p3.hlsl

@@ -0,0 +1,18 @@
+// RUN: %dxc -T ps_6_0 -E main -fspv-target-env=vulkan1.3
+
+// CHECK:      OpEntryPoint Fragment
+// CHECK-SAME: %gl_HelperInvocation
+
+// CHECK:      OpDecorate %gl_HelperInvocation BuiltIn HelperInvocation
+
+// CHECK:      %gl_HelperInvocation = OpVariable %_ptr_Input_bool Input
+
+float4 main() : SV_Target {
+// CHECK:      [[val:%\d+]] = OpLoad %bool %gl_HelperInvocation
+// CHECK:      OpBranchConditional [[val]]
+    float ret = 1.0;
+
+    if (IsHelperLane()) ret = 2.0;
+
+    return ret;
+}

tools/clang/unittests/SPIRV/CodeGenSpirvTest.cpp

@@ -1493,6 +1493,12 @@ TEST_F(FileTest, IntrinsicsSM66PackClampU8S8) {
 TEST_F(FileTest, IntrinsicsSM66Unpack) {
   runFileTest("intrinsics.sm6_6.unpack.hlsl");
 }
+TEST_F(FileTest, IntrinsicsSM66IsHelperLane) {
+  runFileTest("intrinsics.sm6_6.ishelperlane.hlsl");
+}
+TEST_F(FileTest, IntrinsicsSM66IsHelperLaneVk1p3) {
+  runFileTest("intrinsics.sm6_6.ishelperlane.vk1p3.hlsl");
+}
 
 // For attributes
 TEST_F(FileTest, AttributeEarlyDepthStencil) {