shader: add BVH stack operations

tests/ShaderRayTracingTests.inc

@@ -1,4 +1,45 @@
+void TestTrinityStackInstruction() {
+  namespace D = ShaderRecompiler::Decoder;
+  const std::array code{0xdb840008u, 0x01010a09u,
+                        0xdb840010u, 0x02010a09u, EncodeSopp(0x01)};
+  D::Program decoded;
+  D::DecodeProgram(code, decoded);
+  const auto& first = decoded.instructions.front();
+  Check(first.opcode == D::Opcode::DS_BVH_STACK_PUSH8_POP1_RTN_B32 &&
+            first.src_count == 3 && first.offset == 8 && first.dst.reg == 1 &&
+            first.src0.reg == 9 && first.src1.reg == 10 && first.src2.reg == 1,
+        "Trinity stack operands or capacity were not decoded");
+  ShaderComputeInputInfo compute{};
+  compute.lds_size_dwords = 1024;
+  auto options = MakeCompileOptions(ShaderType::Compute);
+  options.input_info.compute = &compute;
+  const auto result = RecompileForTest(code, options);
+  Check(CountSourceOccurrences(result.ir_dump, " = BvhStack ") == 2 &&
+            result.program.info.uses_lds && result.program.info.bvh_stack &&
+            !result.program.info.shared_int64_atomics,
+        "unused stack results discarded LDS writes or selected 64-bit atomics");
+  Check(SpirvInstructionOpcodeCount(result.spirv, 54u) == 2 &&
+            SpirvInstructionOpcodeCount(result.spirv, 246u) == 1,
+        "Trinity stack calls duplicated the function or unrolled its eight pushes");
+  CheckSpirvBinaryValidates(result.spirv);
+  compute.lds_storage = true;
+  CheckSpirvBinaryValidates(RecompileForTest(code, options).spirv);
+  options = MakeCompileOptions(ShaderType::Pixel);
+  CheckSpirvBinaryValidates(RecompileForTest(code, options).spirv);
+  for (const auto words : {std::array{0xdb860008u, 0x01010a09u},
+                           std::array{0xdb840007u, 0x01010a09u},
+                           std::array{0xdb840020u, 0x01010a09u},
+                           std::array{0xdb840008u, 0x01f90a09u},
+                           std::array{0xdb840008u, 0x09010a09u}}) {
+    const std::array invalid{words[0], words[1], EncodeSopp(0x01)};
+    D::DecodeProgram(invalid, decoded);
+    Check(decoded.instructions[0].opcode == D::Opcode::UNSUPPORTED,
+          "unsupported stack encoding was silently accepted");
+  }
+}
+
 void TestRayTracingInstructions() {
+  TestTrinityStackInstruction();
   namespace D = ShaderRecompiler::Decoder;
   const std::array code{
       0xf1989f01u, 0x00081014u,