spirv-fuzz: have outliner split blocks that start with OpPhi to make it apply more aggressively #3094
Description
We decided to simplify the spirv-fuzz outlining transformation by having it not apply when the region to be outlined starts with OpPhi - see discussion on #3078.
The idea is to handle the OpPhi case in practice by splitting a relevant block, applying outlining, and then doing a corresponding merge.
This issue is to track that feature, and the test below (originally for handling the OpPhi case directly) should be re-worked into a new test for the feature.
TEST(TransformationOutlineFunctionTest,
DISABLED_OutlineRegionThatStartsWithOpPhi) {
std::string shader = R"(
OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %4 "main"
OpExecutionMode %4 OriginUpperLeft
OpSource ESSL 310
OpName %4 "main"
%2 = OpTypeVoid
%3 = OpTypeFunction %2
%6 = OpTypeBool
%7 = OpConstantTrue %6
%4 = OpFunction %2 None %3
%5 = OpLabel
%20 = OpCopyObject %6 %7
OpBranch %21
%21 = OpLabel
%22 = OpPhi %6 %20 %5
%23 = OpCopyObject %6 %22
OpBranch %24
%24 = OpLabel
%25 = OpCopyObject %6 %23
%26 = OpCopyObject %6 %22
OpReturn
OpFunctionEnd
)";
const auto env = SPV_ENV_UNIVERSAL_1_5;
const auto consumer = nullptr;
const auto context = BuildModule(env, consumer, shader, kFuzzAssembleOption);
ASSERT_TRUE(IsValid(env, context.get()));
FactManager fact_manager;
TransformationOutlineFunction transformation(
/*entry_block*/ 21,
/*exit_block*/ 21,
/*new_function_struct_return_type_id*/ 200,
/*new_function_type_id*/ 201,
/*new_function_id*/ 202,
/*new_function_first_block*/ 203,
/*new_function_region_entry_block*/ 204,
/*new_caller_result_id*/ 205,
/*new_callee_result_id*/ 206,
/*input_id_to_fresh_id*/ {{22, 207}},
/*output_id_to_fresh_id*/ {{23, 208}});
ASSERT_TRUE(transformation.IsApplicable(context.get(), fact_manager));
transformation.Apply(context.get(), &fact_manager);
ASSERT_TRUE(IsValid(env, context.get()));
std::string after_transformation = R"(
OpCapability Shader
%1 = OpExtInstImport "GLSL.std.450"
OpMemoryModel Logical GLSL450
OpEntryPoint Fragment %4 "main"
OpExecutionMode %4 OriginUpperLeft
OpSource ESSL 310
OpName %4 "main"
%2 = OpTypeVoid
%3 = OpTypeFunction %2
%6 = OpTypeBool
%7 = OpConstantTrue %6
%200 = OpTypeStruct %6
%201 = OpTypeFunction %200 %6
%4 = OpFunction %2 None %3
%5 = OpLabel
%20 = OpCopyObject %6 %7
OpBranch %21
%21 = OpLabel
%22 = OpPhi %6 %20 %5
%205 = OpFunctionCall %200 %202 %22
%23 = OpCompositeExtract %6 %205 0
OpBranch %24
%24 = OpLabel
%25 = OpCopyObject %6 %23
%26 = OpCopyObject %6 %22
OpReturn
OpFunctionEnd
%202 = OpFunction %200 None %201
%207 = OpFunctionParameter %6
%203 = OpLabel
OpBranch %204
%204 = OpLabel
%208 = OpCopyObject %6 %207
%206 = OpCompositeConstruct %200 %208
OpReturnValue %206
OpFunctionEnd
)";
ASSERT_TRUE(IsEqual(env, after_transformation, context.get()));
}