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[Fix] (DirectVulkan, ShaderTranspiler, MG_IntegrationTest, SelfTest, TraceReplay): use native subgroups and patch iterationRP's under-declared scratch

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iterationRP's Program 203 declares shared vec2 prefixSumCache[32] for a
512-invocation workgroup indexed by gl_SubgroupID; any device narrower
than 16 lanes partitions into more than 32 subgroups and the pack writes
shared memory out of bounds (heap corruption on lavapipe's CPU
rasterizer, ssim 0.028 on the CI retrace). Fix it where the fault lies -
in the fixture - and keep the GL contract sound everywhere else:

- FixIterationRPSubgroupScratchPass: fingerprint-gated SPIR-V pass that
  grows exactly that array to ceil(invocations/width) entries on sub-16-lane devices; every other module passes through byte-identical.
- DeriveNumSubgroupsPass stays default-on for the Adreno topology bug
  and is made spec-sound: pipelines request REQUIRE_FULL_SUBGROUPS
  whenever the workgroup shape makes the flag legal (computeFullSubgroups
  enabled, local_size_x a multiple of the native width, subgroup count
  within maxComputeWorkgroupSubgroups).
- EmulateSubgroupsPass: 32-lane virtual-subgroup lowering kept in-tree
  as a last resort, enabled only by MOBILEGL_MAGMA_EMULATE_SUBGROUP=1 on
  devices with no native subgroup support; fails closed on extended
  subgroup instructions and on modules whose added scratch would exceed
  maxComputeSharedMemorySize.
- IterationRPFirstReductionScenario skips gracefully outside the pack's
  16..256-lane source domain; the new IterationRPScratchFixScenario runs
  the fixture-shaped reduction on any width and asserts the exact
  width-independent total. DriverPost keeps reporting FAIL on
  out-of-domain devices.
- Program203 -> IterationRP rename throughout; the per-trace
  num_subgroups_quirk plumbing is removed from the trace replayer, JNI
  chain, and CI workflows.
This commit is contained in:
swung0x48
2026-08-19 09:48:11 -04:00
parent 2b6c2b561c
commit d8576a2ed3
38 changed files with 3354 additions and 396 deletions
Download Patch File Download Diff File Expand all files Collapse all files
MobileGL/MG_IntegrationTest/CMakeLists.txt
+2 -1
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@@ -68,7 +68,8 @@ add_executable(MobileGLIntegrationTest
Scenarios/DoublePrecisionScenario.cpp
Scenarios/UniformInitializerScenario.cpp
Scenarios/SwizzleAccessRoutineScenario.cpp
Scenarios/Program203FirstReductionScenario.cpp
Scenarios/IterationRPFirstReductionScenario.cpp
Scenarios/IterationRPScratchFixScenario.cpp
Scenarios/ProgramPipelineScenario.cpp
Scenarios/ImageLoadStoreSsoScenario.cpp
Scenarios/ImageTargetKindScenario.cpp
MobileGL/MG_IntegrationTest/Scenarios/Program203FirstReductionScenario.cpp → MobileGL/MG_IntegrationTest/Scenarios/IterationRPFirstReductionScenario.cpp
+44 -24
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@@ -1,4 +1,4 @@
// MobileGL - MobileGL/MG_IntegrationTest/Scenarios/Program203FirstReductionScenario.cpp
// MobileGL - MobileGL/MG_IntegrationTest/Scenarios/IterationRPFirstReductionScenario.cpp
// Copyright (c) 2026 MobileGL-Dev
// Licensed under the GNU Lesser General Public License v3.0:
// https://www.gnu.org/licenses/gpl-3.0.txt
@@ -6,9 +6,9 @@
// SPDX-License-Identifier: LGPL-3.0-only
// End of Source File Header
//
// Scenario - PROGRAM 203'S FIRST SUBGROUP REDUCTION.
// Scenario - ITERATIONRP'S FIRST SUBGROUP REDUCTION.
//
// Program 203 reduces a 32 x 16 exposure tile with a vector subgroup inclusive add,
// iterationRP reduces a 32 x 16 exposure tile with a vector subgroup inclusive add,
// then a shared-memory scan of subgroup totals. The source assumes that every
// subgroup has a last lane, that there are 2..32 subgroups, and that local index
// 511 belongs to the last subgroup and its last lane. Those are source assumptions,
@@ -133,6 +133,17 @@ namespace MGITest {
std::array<GLint, 3> maxWorkGroupSize{};
bool queryHadError = false;
// iterationRP's source contract needs gl_NumSubgroups in [2, 32] for its 512
// invocations, i.e. an advertised subgroup width in [16, 256]. A device
// outside that window (lavapipe's 8-lane subgroups give 64 subgroups) cannot
// run the fixture's verbatim reduction at all, so the scenario SKIPS there -
// the pack itself replays through the FixIterationRPSubgroupScratch patch, which
// this probe deliberately does not model. The width only gates the domain;
// lane placement and group counts still come from observed values alone.
bool SubgroupWidthInSourceDomain() const {
return subgroupSize >= 16 && subgroupSize <= 256;
}
bool SupportsProbe() const {
const auto stages = static_cast<GLbitfield>(supportedStages);
const auto features = static_cast<GLbitfield>(supportedFeatures);
@@ -140,6 +151,7 @@ namespace MGITest {
(stages & GL_COMPUTE_SHADER_BIT) != 0 &&
(features & (GL_SUBGROUP_FEATURE_BASIC_BIT_KHR | GL_SUBGROUP_FEATURE_ARITHMETIC_BIT_KHR)) ==
(GL_SUBGROUP_FEATURE_BASIC_BIT_KHR | GL_SUBGROUP_FEATURE_ARITHMETIC_BIT_KHR) &&
SubgroupWidthInSourceDomain() &&
maxComputeStorageBlocks >= 2 && maxStorageBindings >= 2 &&
maxWorkGroupInvocations >= static_cast<GLint>(kInvocationCount) && maxWorkGroupSize[0] >= 32 &&
maxWorkGroupSize[1] >= 16 && maxWorkGroupSize[2] >= 1;
@@ -159,6 +171,12 @@ namespace MGITest {
if ((features & requiredFeatures) != requiredFeatures) {
missing.emplace_back("basic|arithmetic in GL_SUBGROUP_SUPPORTED_FEATURES_KHR");
}
if (!SubgroupWidthInSourceDomain()) {
missing.emplace_back(
"GL_SUBGROUP_SIZE_KHR in [16, 256] (iterationRP's source contract needs "
"gl_NumSubgroups in [2, 32] for 512 invocations; width " +
std::to_string(subgroupSize) + " is outside the fixture's domain)");
}
if (maxComputeStorageBlocks < 2 || maxStorageBindings < 2) {
missing.emplace_back("two compute SSBO bindings");
}
@@ -194,7 +212,7 @@ namespace MGITest {
}
void PrintMetadata(const CapabilityInfo& info, std::ostream& output) {
output << "Program203FirstReductionScenario metadata: "
output << "IterationRPFirstReductionScenario metadata: "
<< "GL_SUBGROUP_SIZE_KHR=" << info.subgroupSize
<< ", GL_SUBGROUP_SUPPORTED_STAGES_KHR=0x" << std::hex
<< static_cast<GLbitfield>(info.supportedStages)
@@ -243,7 +261,7 @@ layout(std430, binding = 0) readonly buffer Input {
)";
// Only the expression producing tileExposure differs between the two
// tests. The remainder is the program-203 first reduction, with stores
// tests. The remainder is the iterationRP first reduction, with stores
// placed after its existing barriers to expose each handoff.
constexpr const char* kSampledTileExposure = R"(
vec2 texCoord = (vec2(gl_GlobalInvocationID.xy) + 0.5) *
@@ -506,7 +524,7 @@ layout(std430, binding = 0) readonly buffer Input {
if (!IsQuietNanSentinel(reduction.z) || !IsQuietNanSentinel(reduction.w) ||
!IsQuietNanSentinel(output.finalAverage[slot])) {
std::ostringstream message;
message << "program 203 source reduction has no valid contract for gl_NumSubgroups="
message << "iterationRP source reduction has no valid contract for gl_NumSubgroups="
<< reportedNumSubgroups << "; localIndex " << localIndex
<< " did not preserve its qNaN source-reduction sentinel";
return Failure("source domain", message.str());
@@ -514,7 +532,7 @@ layout(std430, binding = 0) readonly buffer Input {
for (std::size_t stage = 0; stage < kScanStageCount; ++stage) {
if (!IsQuietNanSentinel(output.scanAfter[stage][slot])) {
std::ostringstream message;
message << "program 203 source reduction has no valid contract for gl_NumSubgroups="
message << "iterationRP source reduction has no valid contract for gl_NumSubgroups="
<< reportedNumSubgroups << "; localIndex " << localIndex << ", scan stage " << stage
<< " did not preserve its qNaN source-reduction sentinel";
return Failure("source domain", message.str());
@@ -522,12 +540,12 @@ layout(std430, binding = 0) readonly buffer Input {
}
}
std::ostringstream message;
message << "program 203 source reduction has no valid contract for observed gl_NumSubgroups="
message << "iterationRP source reduction has no valid contract for observed gl_NumSubgroups="
<< reportedNumSubgroups << " (requires 2..32); native subgroup results were recorded";
return Failure("source domain", message.str());
}
// 4. Program-203 source writer and first shared-memory handoff.
// 4. iterationRP source writer and first shared-memory handoff.
std::vector<std::size_t> sourceWriter(reportedNumSubgroups, kNoSlot);
for (std::uint32_t subgroupID = 0; subgroupID < reportedNumSubgroups; ++subgroupID) {
std::size_t writerCount = 0;
@@ -541,7 +559,7 @@ layout(std430, binding = 0) readonly buffer Input {
if (writerCount != 1u) {
std::ostringstream message;
message << "subgroupID " << subgroupID << " has " << writerCount
<< " recorded lane(s) where laneID == subgroupSize - 1; program 203 leaves that "
<< " recorded lane(s) where laneID == subgroupSize - 1; iterationRP leaves that "
"shared-cache entry unwritten";
return Failure("source writer", message.str());
}
@@ -633,7 +651,7 @@ layout(std430, binding = 0) readonly buffer Input {
index511Subgroup.z == ownerResult.highestObservedSubgroup;
if (!ownerResult.index511IsSourceLastLaneWriter || !ownerResult.index511IsHighestSubgroupMember) {
std::ostringstream message;
message << "program 203 topology incompatibility: localIndex 511 is sourceLastLaneWriter="
message << "iterationRP topology incompatibility: localIndex 511 is sourceLastLaneWriter="
<< ownerResult.index511IsSourceLastLaneWriter << ", highestSubgroupMember="
<< ownerResult.index511IsHighestSubgroupMember << " (subgroupID=" << index511Subgroup.z
<< ", highest observed subgroupID=" << ownerResult.highestObservedSubgroup << ')';
@@ -650,7 +668,7 @@ layout(std430, binding = 0) readonly buffer Input {
const float expectedTotal = mode == InputMode::IndexedSsbo ? 131328.0f : sampledExpectedTotal;
if (!SameBits(total, expectedTotal) || !SameBits(mergedPrefix[index511Slot], expectedTotal)) {
std::ostringstream message;
message << "program 203 source total was " << FormatFloat(mergedPrefix[index511Slot])
message << "iterationRP source total was " << FormatFloat(mergedPrefix[index511Slot])
<< " (native total " << FormatFloat(total) << "), expected " << FormatFloat(expectedTotal);
ownerResult.ok = false;
ownerResult.phase = "final average";
@@ -675,9 +693,9 @@ layout(std430, binding = 0) readonly buffer Input {
bool includeScanStages) {
PrintMetadata(capabilities, std::cout);
if (validation.ok) {
std::cout << "Program203FirstReductionScenario firstFailure=none\n";
std::cout << "IterationRPFirstReductionScenario firstFailure=none\n";
} else {
std::cout << "Program203FirstReductionScenario firstFailure=" << validation.phase << ": "
std::cout << "IterationRPFirstReductionScenario firstFailure=" << validation.phase << ": "
<< validation.message << '\n';
}
std::cout << "localIndex,localX,localY,localZ,subgroupSize,numSubgroups,subgroupID,laneID,input,"
@@ -702,17 +720,19 @@ layout(std430, binding = 0) readonly buffer Input {
}
}
class Program203FirstReductionScenario : public ScenarioTest {
class IterationRPFirstReductionScenario : public ScenarioTest {
protected:
void SetUp() override {
ScenarioTest::SetUp();
if (!Ready()) return;
m_capabilities = QueryCapabilities();
// GL_SUBGROUP_SIZE_KHR is diagnostic only. It is deliberately
// never used to infer lane placement or an expected group count.
// GL_SUBGROUP_SIZE_KHR gates only whether the fixture's source contract
// can hold on this device (SubgroupWidthInSourceDomain); it is
// deliberately never used to infer lane placement or an expected group
// count - those come from observed values alone.
PrintMetadata(m_capabilities, std::cout);
RecordProperty("program203_gl_subgroup_size_khr", std::to_string(m_capabilities.subgroupSize));
RecordProperty("iterationrp_gl_subgroup_size_khr", std::to_string(m_capabilities.subgroupSize));
if (!m_capabilities.SupportsProbe()) {
GTEST_SKIP() << "subgroup probe requires " << m_capabilities.MissingRequirements();
}
@@ -839,13 +859,13 @@ layout(std430, binding = 0) readonly buffer Input {
const ValidationResult validation = ValidateProbe(output, mode);
if (validation.ownerEvaluated) {
RecordProperty("program203_index511_source_last_lane_writer",
RecordProperty("iterationrp_index511_source_last_lane_writer",
validation.index511IsSourceLastLaneWriter ? "true" : "false");
RecordProperty("program203_index511_highest_subgroup_member",
RecordProperty("iterationrp_index511_highest_subgroup_member",
validation.index511IsHighestSubgroupMember ? "true" : "false");
RecordProperty("program203_highest_observed_subgroup",
RecordProperty("iterationrp_highest_observed_subgroup",
std::to_string(validation.highestObservedSubgroup));
std::cout << "Program203FirstReductionScenario owner: localIndex511 sourceLastLaneWriter="
std::cout << "IterationRPFirstReductionScenario owner: localIndex511 sourceLastLaneWriter="
<< validation.index511IsSourceLastLaneWriter << ", highestSubgroupMember="
<< validation.index511IsHighestSubgroupMember << ", highestObservedSubgroup="
<< validation.highestObservedSubgroup << '\n';
@@ -865,12 +885,12 @@ layout(std430, binding = 0) readonly buffer Input {
} // namespace
TEST_F(Program203FirstReductionScenario, SampledRgba32fFirstAverage) {
TEST_F(IterationRPFirstReductionScenario, SampledRgba32fFirstAverage) {
if (!Ready() || IsSkipped()) return;
RunAndValidate(InputMode::SampledRgba32f);
}
TEST_F(Program203FirstReductionScenario, IndexedInputTopologyAndReduction) {
TEST_F(IterationRPFirstReductionScenario, IndexedInputTopologyAndReduction) {
if (!Ready() || IsSkipped()) return;
RunAndValidate(InputMode::IndexedSsbo);
}
MobileGL/MG_IntegrationTest/Scenarios/IterationRPScratchFixScenario.cpp
+222
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@@ -0,0 +1,222 @@
// MobileGL - MobileGL/MG_IntegrationTest/Scenarios/IterationRPScratchFixScenario.cpp
// Copyright (c) 2026 MobileGL-Dev
// Licensed under the GNU Lesser General Public License v3.0:
// https://www.gnu.org/licenses/gpl-3.0.txt
// https://www.gnu.org/licenses/lgpl-3.0.txt
// SPDX-License-Identifier: LGPL-3.0-only
// End of Source File Header
//
// Scenario - THE FIXTURE-SHAPED SUBGROUP REDUCTION, ON WHATEVER WIDTH THE DEVICE HAS.
//
// iterationRP's auto-exposure pass declares `shared vec2 prefixSumCache[32]` for a
// 512-invocation workgroup and combines per-subgroup subtotals through
// prefixSumCache[gl_SubgroupID]. The algorithm is width-agnostic; only the static 32
// bakes in "at most 32 subgroups", which every desktop capture satisfies and an 8-lane
// device (lavapipe: 64 subgroups) does not. DirectVulkan patches exactly that with
// FixIterationRPSubgroupScratchPass, growing the array to ceil(invocations / native
// width) on the modules that match the pack's reduction fingerprint.
//
// This scenario replays the fixture's reduction shape verbatim - the same 32-entry
// declaration, the same last-lane handoff, the same findMSB combine loop, and NO
// domain guard - and asserts only the width-independent result: the workgroup total.
// The inputs are small integers, so the fp32 sum is exact under any lane order and any
// association; a correct run produces the exact constant on a 4-lane device and a
// 128-lane device alike. Without the patch, a sub-16-lane device indexes the
// 32-entry array out of bounds - on lavapipe that is literal heap corruption - and
// this scenario is the regression test that keeps the patch working, and it runs on every device that
// has basic+arithmetic compute subgroups (unlike IterationRPFirstReductionScenario,
// which probes the UNREPAIRED source contract and must skip outside [16, 256]).
#include <cstdint>
#include <cstring>
#include <string>
#include "../Harness/HeadlessGL.h"
#include "../Harness/ScenarioFixture.h"
#ifdef GLAPI
#undef GLAPI
#endif
#define GL_GLEXT_PROTOTYPES
#include <GL/gl.h>
#include <GL/glcorearb.h>
#undef GL_GLEXT_PROTOTYPES
namespace MGITest {
namespace {
constexpr std::uint32_t kInvocationCount = 512u;
// sum of 0..511, exactly representable and associativity-proof in fp32.
constexpr float kExpectedTotal = 130816.0f;
constexpr const char* kComputeSource = R"(#version 430 core
#extension GL_KHR_shader_subgroup_basic : require
#extension GL_KHR_shader_subgroup_arithmetic : require
layout(local_size_x = 32, local_size_y = 16, local_size_z = 1) in;
layout(std430, binding = 0) buffer Output {
float total;
uint numSubgroups;
uint maxSubgroupId;
} outputData;
shared vec2 prefixSumCache[32];
void main() {
vec2 sampleLuminance = vec2(float(gl_LocalInvocationIndex), 0.0);
sampleLuminance = subgroupInclusiveAdd(sampleLuminance);
if (gl_SubgroupInvocationID == gl_SubgroupSize - 1u)
prefixSumCache[gl_SubgroupID] = sampleLuminance;
barrier();
uint loopLength = uint(findMSB(gl_NumSubgroups));
loopLength += uint(gl_NumSubgroups - (1u << (loopLength - 1u)) > 0u);
for (uint scanStage = 0u; scanStage < loopLength; ++scanStage) {
if ((gl_SubgroupID & (1u << scanStage)) > 0u) {
sampleLuminance += prefixSumCache[(gl_SubgroupID >> scanStage << scanStage) - 1u];
if (gl_SubgroupInvocationID == gl_SubgroupSize - 1u)
prefixSumCache[gl_SubgroupID] = sampleLuminance;
}
barrier();
}
if (gl_LocalInvocationIndex == 511u) {
outputData.total = sampleLuminance.x;
outputData.numSubgroups = gl_NumSubgroups;
}
atomicMax(outputData.maxSubgroupId, gl_SubgroupID);
}
)";
struct OutputBlock {
float total = -1.0f;
std::uint32_t numSubgroups = 0;
std::uint32_t maxSubgroupId = 0;
};
bool HasExtension(const char* wanted) {
GLint extensionCount = 0;
glGetIntegerv(GL_NUM_EXTENSIONS, &extensionCount);
for (GLint i = 0; i < extensionCount; ++i) {
const auto* extension =
reinterpret_cast<const char*>(glGetStringi(GL_EXTENSIONS, static_cast<GLuint>(i)));
if (extension != nullptr && std::string(extension) == wanted) return true;
}
return false;
}
class IterationRPScratchFixScenario : public ScenarioTest {
protected:
void SetUp() override {
ScenarioTest::SetUp();
if (!Ready()) return;
GLint stages = 0;
GLint features = 0;
GLint invocations = 0;
const bool subgroupExtension = HasExtension("GL_KHR_shader_subgroup");
if (subgroupExtension) {
glGetIntegerv(GL_SUBGROUP_SUPPORTED_STAGES_KHR, &stages);
glGetIntegerv(GL_SUBGROUP_SUPPORTED_FEATURES_KHR, &features);
}
glGetIntegerv(GL_MAX_COMPUTE_WORK_GROUP_INVOCATIONS, &invocations);
const GLbitfield requiredFeatures =
GL_SUBGROUP_FEATURE_BASIC_BIT_KHR | GL_SUBGROUP_FEATURE_ARITHMETIC_BIT_KHR;
if (!subgroupExtension || (static_cast<GLbitfield>(stages) & GL_COMPUTE_SHADER_BIT) == 0 ||
(static_cast<GLbitfield>(features) & requiredFeatures) != requiredFeatures ||
invocations < static_cast<GLint>(kInvocationCount)) {
GTEST_SKIP() << "needs GL_KHR_shader_subgroup basic+arithmetic in compute and a "
"512-invocation workgroup";
}
m_program = CompileComputeProgram(kComputeSource);
ASSERT_NE(m_program, 0u) << m_buildLog;
glGenBuffers(1, &m_output);
glBindBuffer(GL_SHADER_STORAGE_BUFFER, m_output);
// maxSubgroupId starts at zero HOST-side: the word is touched only by
// atomicMax during the dispatch, since a plain shader-side zeroing store
// would race the other invocations' atomics (barrier() orders shared
// memory, not SSBO stores).
const OutputBlock poison{-1.0f, 0xa5a5a5a5u, 0u};
glBufferData(GL_SHADER_STORAGE_BUFFER, sizeof(OutputBlock), &poison, GL_DYNAMIC_READ);
glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 0, m_output);
}
void TearDown() override {
if (!Ready()) return;
glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 0, 0);
glBindBuffer(GL_SHADER_STORAGE_BUFFER, 0);
if (m_output != 0) glDeleteBuffers(1, &m_output);
if (m_program != 0) glDeleteProgram(m_program);
}
unsigned int CompileComputeProgram(const char* source) {
const GLuint shader = glCreateShader(GL_COMPUTE_SHADER);
glShaderSource(shader, 1, &source, nullptr);
glCompileShader(shader);
GLint compiled = 0;
glGetShaderiv(shader, GL_COMPILE_STATUS, &compiled);
if (compiled == GL_FALSE) {
char log[2048] = {};
glGetShaderInfoLog(shader, sizeof(log) - 1, nullptr, log);
m_buildLog = std::string("compute shader did not compile: ") + log;
glDeleteShader(shader);
return 0;
}
const GLuint program = glCreateProgram();
glAttachShader(program, shader);
glLinkProgram(program);
glDeleteShader(shader);
GLint linked = 0;
glGetProgramiv(program, GL_LINK_STATUS, &linked);
if (linked == GL_FALSE) {
char log[2048] = {};
glGetProgramInfoLog(program, sizeof(log) - 1, nullptr, log);
m_buildLog = std::string("compute program did not link: ") + log;
glDeleteProgram(program);
return 0;
}
return program;
}
OutputBlock Dispatch() {
glUseProgram(m_program);
glDispatchCompute(1, 1, 1);
glMemoryBarrier(GL_BUFFER_UPDATE_BARRIER_BIT);
OutputBlock block{};
glBindBuffer(GL_SHADER_STORAGE_BUFFER, m_output);
glGetBufferSubData(GL_SHADER_STORAGE_BUFFER, 0, sizeof(OutputBlock), &block);
return block;
}
GLuint m_program = 0;
GLuint m_output = 0;
std::string m_buildLog;
};
} // namespace
TEST_F(IterationRPScratchFixScenario, FixtureShapedReductionSumsEveryInvocation) {
const OutputBlock block = Dispatch();
EXPECT_EQ(glGetError(), static_cast<GLenum>(GL_NO_ERROR));
// The topology diagnostics catch the failure modes by name before the sum does:
// an out-of-bounds handoff corrupts the total, a wrong gl_NumSubgroups breaks
// the combine loop's length.
ASSERT_NE(block.numSubgroups, 0xa5a5a5a5u) << "invocation 511 never reached its store";
EXPECT_GE(block.numSubgroups, 1u);
EXPECT_LE(block.numSubgroups, kInvocationCount);
EXPECT_LT(block.maxSubgroupId, block.numSubgroups)
<< "gl_SubgroupID exceeds gl_NumSubgroups - the inconsistency "
"DeriveNumSubgroupsPass exists to repair";
// Integer-valued fp32 inputs: the workgroup total is exact under any subgroup
// width, lane order, and association. This is the value iterationRP's exposure
// average is built from; without FixIterationRPSubgroupScratchPass an 8-lane
// device writes prefixSumCache[32..63] out of bounds and this comparison fails.
EXPECT_EQ(block.total, kExpectedTotal)
<< "workgroup reduction produced " << block.total << " with gl_NumSubgroups="
<< block.numSubgroups;
}
} // namespace MGITest