Lower finite GPU-selected image descriptors through shared indirect bindings

src/graphics/shader/recompiler/ShaderRecompiler.cpp

@@ -617,7 +617,6 @@ TranslateResult TranslateProgram(std::span<const uint32_t> code, const CompileOp
 		}
 	}
 	IR::TrackResources(ir, decoded, native_cfg);
-	IR::EliminateDeadCode(ir.blocks);
 	TranslateResult result;
 	result.program = std::move(ir);
 	if (options.dump_ir) {

src/graphics/shader/recompiler/ir/ShaderIR.h

@@ -476,6 +476,7 @@ struct DescriptorSource {
 		uint32_t table_offset    = 0;
 		Value    key_count;
 		Value    selector_mask;
+		std::vector<uint32_t> sources;
 
 		bool operator==(const IndirectImage& other) const = default;
 	};

src/graphics/shader/recompiler/ir/passes/ResourceMaterialization.cpp

@@ -227,100 +227,114 @@ bool ReadScalarTable(uint64_t base, uint64_t size, uint64_t dynamic_offset,
 
 bool MaterializeIndirectImage(const ResourcePlan& program,
                               const DescriptorSource::IndirectImage& indirect,
-                              const DescriptorValue& material_value,
-                              const DescriptorValue& table_value, uint32_t image_index,
+                              uint32_t image_index,
                               const SrtRuntime& runtime, SrtWalker& clean,
                               ResourceSnapshot& snapshot,
                               ResourceSpecialization& specialization) {
+	const auto& sources = indirect.sources;
+	auto& keys = program.material_keys;
 	uint64_t table_base = 0;
 	uint64_t table_size = UINT64_MAX; // Scalar addresses have no buffer descriptor bounds.
-	ShaderBufferResource table;
-	if (table_value.dword_count == 2u) {
-		table_base = (static_cast<uint64_t>(table_value.dwords[1]) << 32u) | table_value.dwords[0];
-	} else if (DecodeBufferDescriptor(table_value, table)) {
-		table_base = table.Base48();
-		table_size = table.GetSize();
-	} else {
-		return false;
-	}
-	auto& keys = program.material_keys;
-	keys.clear();
-	if (indirect.material_source == UINT32_MAX) {
-		uint32_t key_count = 0;
-		const bool evaluated = clean.Evaluate(indirect.key_count, key_count);
-		if (std::bit_cast<int32_t>(key_count) <= 0) key_count = 0;
-		if (table_value.dword_count != 2u || !evaluated ||
-		    key_count > MaxIndirectImageProbes ||
-		    uint64_t {indirect.table_offset} + uint64_t {key_count} * 32u > UINT32_MAX + 1ull) {
+	if (sources.empty()) {
+		keys.clear();
+		DescriptorValue material_value;
+		DescriptorValue table_value;
+		if ((indirect.material_source != UINT32_MAX &&
+		     !clean.EvaluateDescriptor(indirect.material_source, material_value)) ||
+		    !clean.EvaluateDescriptor(indirect.table_source, table_value)) {
 			return false;
 		}
-		keys.resize(key_count);
-		std::iota(keys.begin(), keys.end(), 0u);
-	} else if (!indirect.selector_mask.IsEmpty()) {
-		uint32_t mask = 0;
-		uint32_t count = 0;
-		if (material_value.dword_count != 2u || table_value.dword_count != 2u ||
-		    !clean.Evaluate(indirect.selector_mask, mask) ||
-		    !clean.Evaluate(indirect.key_count, count) || count == 0u || count > 32u) {
+		ShaderBufferResource table;
+		if (table_value.dword_count == 2u) {
+			table_base = (static_cast<uint64_t>(table_value.dwords[1]) << 32u) | table_value.dwords[0];
+		} else if (DecodeBufferDescriptor(table_value, table)) {
+			table_base = table.Base48();
+			table_size = table.GetSize();
+		} else {
 			return false;
 		}
-		if (count < 32u) mask &= (1u << count) - 1u;
-		const auto material_base =
-		    (static_cast<uint64_t>(material_value.dwords[1]) << 32u) | material_value.dwords[0];
-		keys.reserve(std::popcount(mask));
-		while (mask != 0u) {
-			const auto index = std::countr_zero(mask);
-			const auto offset = static_cast<uint64_t>(indirect.selector_offset) +
-			                    static_cast<uint64_t>(index) * indirect.selector_stride;
-			if (offset > UINT32_MAX) return false;
-			uint32_t key = 0;
-			if (!ReadScalarTable(material_base, UINT64_MAX, static_cast<uint32_t>(offset),
-			                     runtime, {&key, 1})) return false;
-			keys.push_back(key);
-			mask &= mask - 1u;
-		}
-		std::ranges::sort(keys);
-		keys.erase(std::unique(keys.begin(), keys.end()), keys.end());
-	} else {
-		ShaderBufferResource material;
-		if (!DecodeBufferDescriptor(material_value, material) || table_value.dword_count != 4u ||
-		    material.Stride() != indirect.selector_stride) {
-			return false;
-		}
-		// The first aligned offset includes the immediate added after shader U32 arithmetic.
-		const auto step = std::max<uint64_t>(4u,
-		    std::gcd<uint64_t>(indirect.selector_stride, uint64_t {1} << 32u));
-		const uint64_t first = indirect.selector_offset;
-		const auto size = material.GetSize();
-		const auto limit = std::min(first + (uint64_t {1} << 32u) - step, size >= 4u ? size - 4u : 0u);
-		const auto probe_count = size >= 4u && first <= limit ? (limit - first) / step + 1u : 0u;
-		if (probe_count > MaxIndirectImageProbes) {
-			return false;
-		}
-		keys.reserve(static_cast<size_t>(probe_count) + 1u);
-		keys.push_back(0u);
-		for (uint64_t probe = 0, offset = first; probe < probe_count; ++probe, offset += step) {
-			uint32_t key = 0;
-			if (!ReadScalarTable(material.Base48(), size, offset, runtime, {&key, 1})) {
+		if (indirect.material_source == UINT32_MAX) {
+			uint32_t key_count = 0;
+			const bool evaluated = clean.Evaluate(indirect.key_count, key_count);
+			if (std::bit_cast<int32_t>(key_count) <= 0) key_count = 0;
+			if (table_value.dword_count != 2u || !evaluated ||
+			    key_count > MaxIndirectImageProbes ||
+			    uint64_t {indirect.table_offset} + uint64_t {key_count} * 32u > UINT32_MAX + 1ull) {
 				return false;
 			}
-			keys.push_back(key);
+			keys.resize(key_count);
+			std::iota(keys.begin(), keys.end(), 0u);
+		} else if (!indirect.selector_mask.IsEmpty()) {
+			uint32_t mask = 0;
+			uint32_t count = 0;
+			if (material_value.dword_count != 2u || table_value.dword_count != 2u ||
+			    !clean.Evaluate(indirect.selector_mask, mask) ||
+			    !clean.Evaluate(indirect.key_count, count) || count == 0u || count > 32u) {
+				return false;
+			}
+			if (count < 32u) mask &= (1u << count) - 1u;
+			const auto material_base =
+			    (static_cast<uint64_t>(material_value.dwords[1]) << 32u) | material_value.dwords[0];
+			keys.reserve(std::popcount(mask));
+			while (mask != 0u) {
+				const auto index = std::countr_zero(mask);
+				const auto offset = static_cast<uint64_t>(indirect.selector_offset) +
+				                    static_cast<uint64_t>(index) * indirect.selector_stride;
+				if (offset > UINT32_MAX) return false;
+				uint32_t key = 0;
+				if (!ReadScalarTable(material_base, UINT64_MAX, static_cast<uint32_t>(offset),
+				                     runtime, {&key, 1})) return false;
+				keys.push_back(key);
+				mask &= mask - 1u;
+			}
+			std::ranges::sort(keys);
+			keys.erase(std::unique(keys.begin(), keys.end()), keys.end());
+		} else {
+			ShaderBufferResource material;
+			if (!DecodeBufferDescriptor(material_value, material) || table_value.dword_count != 4u ||
+			    material.Stride() != indirect.selector_stride) {
+				return false;
+			}
+			// The first aligned offset includes the immediate added after shader U32 arithmetic.
+			const auto step = std::max<uint64_t>(4u,
+			    std::gcd<uint64_t>(indirect.selector_stride, uint64_t {1} << 32u));
+			const uint64_t first = indirect.selector_offset;
+			const auto size = material.GetSize();
+			const auto limit = std::min(first + (uint64_t {1} << 32u) - step, size >= 4u ? size - 4u : 0u);
+			const auto probe_count = size >= 4u && first <= limit ? (limit - first) / step + 1u : 0u;
+			if (probe_count > MaxIndirectImageProbes) {
+				return false;
+			}
+			keys.reserve(static_cast<size_t>(probe_count) + 1u);
+			keys.push_back(0u);
+			for (uint64_t probe = 0, offset = first; probe < probe_count; ++probe, offset += step) {
+				uint32_t key = 0;
+				if (!ReadScalarTable(material.Base48(), size, offset, runtime, {&key, 1})) {
+					return false;
+				}
+				keys.push_back(key);
+			}
+			std::ranges::sort(keys);
+			keys.erase(std::unique(keys.begin(), keys.end()), keys.end());
 		}
-		std::ranges::sort(keys);
-		keys.erase(std::unique(keys.begin(), keys.end()), keys.end());
 	}
 
 	const auto children_begin = snapshot.images.size();
 	const auto mapping_offset = snapshot.flattened_srt.size();
 	const auto root_image = specialization.images[image_index];
-	snapshot.flattened_srt.resize(mapping_offset + 1u + keys.size() * 2u);
-	snapshot.flattened_srt[mapping_offset] = static_cast<uint32_t>(keys.size());
-	for (uint32_t entry = 0; entry < keys.size(); ++entry) {
-		const auto key = keys[entry];
+	const auto key_count = sources.empty() ? keys.size() : sources.size();
+	snapshot.flattened_srt.resize(mapping_offset + 1u + key_count * 2u);
+	snapshot.flattened_srt[mapping_offset] = static_cast<uint32_t>(key_count);
+	for (uint32_t entry = 0; entry < key_count; ++entry) {
+		const auto key = sources.empty() ? keys[entry] : entry;
 		DescriptorValue candidate;
 		candidate.dword_count = 8u;
-		const auto table_offset = (key << 5u) + indirect.table_offset;
-		if (!ReadScalarTable(table_base, table_size, table_offset, runtime, candidate.dwords)) {
+		if (sources.empty()) {
+			const auto table_offset = (key << 5u) + indirect.table_offset;
+			if (!ReadScalarTable(table_base, table_size, table_offset, runtime, candidate.dwords)) {
+				return false;
+			}
+		} else if (!clean.EvaluateDescriptor(sources[entry], candidate)) {
 			return false;
 		}
 		if (NullImageDescriptor(candidate) ||
@@ -353,7 +367,7 @@ bool MaterializeIndirectImage(const ResourcePlan& program,
 		auto& root = specialization.images[image_index];
 		root.indirect_root = image_index;
 		root.indirect_mapping_offset = static_cast<uint32_t>(mapping_offset);
-		root.indirect_search_iterations = std::bit_width(keys.size());
+		root.indirect_search_iterations = std::bit_width(key_count);
 	}
 	return true;
 }
@@ -936,20 +950,27 @@ ResourcePlan ExtractResourcePlan(const Program& program) {
 		plan.uniform_fill.values[i] = Clone(plan.uniform_fill.values[i]);
 	}
 	plan.clean_flat_slots.resize(plan.srt_reads.size());
-	bool masked_image = false;
+	bool capture_image_reads = false;
 	for (const auto& image: plan.info.images) {
 		const auto* source = Source(plan, image.source);
 		if (source == nullptr || !source->indirect_image.has_value()) {
 			continue;
 		}
 		plan.requires_specialization_memory = true;
-		masked_image |= !source->indirect_image->selector_mask.IsEmpty();
+		capture_image_reads |= !source->indirect_image->selector_mask.IsEmpty() ||
+		                       !source->indirect_image->sources.empty();
 		MarkCleanFlatSlots(plan, Source(plan, source->indirect_image->material_source),
 		                   plan.clean_flat_slots, source->indirect_image->selector_mask);
-		MarkCleanFlatSlots(plan, Source(plan, source->indirect_image->table_source),
-		                   plan.clean_flat_slots);
+		if (source->indirect_image->sources.empty()) {
+			MarkCleanFlatSlots(plan, Source(plan, source->indirect_image->table_source),
+			                   plan.clean_flat_slots);
+		} else {
+			for (const auto candidate: source->indirect_image->sources) {
+				MarkCleanFlatSlots(plan, Source(plan, candidate), plan.clean_flat_slots);
+			}
+		}
 	}
-	plan.capture_specialization_reads = masked_image || !plan.control_flow.empty();
+	plan.capture_specialization_reads = capture_image_reads || !plan.control_flow.empty();
 	// Writable descriptor addresses must come from clean backing for the alias proof.
 	for (const auto& buffer: plan.info.buffers) {
 		if (buffer.written) MarkCleanFlatSlots(plan, Source(plan, buffer.source), plan.clean_flat_slots);
@@ -957,7 +978,7 @@ ResourcePlan ExtractResourcePlan(const Program& program) {
 	for (const auto& image: plan.info.images) {
 		if (image.written) MarkCleanFlatSlots(plan, Source(plan, image.source), plan.clean_flat_slots);
 	}
-	if (masked_image) plan.resource_tracking_complete &= !program.has_address_writes;
+	if (capture_image_reads) plan.resource_tracking_complete &= !program.has_address_writes;
 	return plan;
 }
 
@@ -1039,13 +1060,7 @@ bool MaterializeResources(const ResourcePlan& program, const SrtRuntime& runtime
 				continue;
 			}
 			const auto& indirect = *source->indirect_image;
-			DescriptorValue material;
-			DescriptorValue table;
-			if ((indirect.material_source != UINT32_MAX &&
-			     !clean.EvaluateDescriptor(indirect.material_source, material)) ||
-			    !clean.EvaluateDescriptor(indirect.table_source, table) ||
-			    !MaterializeIndirectImage(program, indirect, material, table, i, observed, clean, snapshot,
-			                              specialization)) {
+			if (!MaterializeIndirectImage(program, indirect, i, observed, clean, snapshot, specialization)) {
 				return false;
 			}
 		} else {

src/graphics/shader/recompiler/ir/passes/ResourceTracking.cpp

@@ -321,8 +321,9 @@ public:
 			for (uint32_t dword = 5u; dword < plan.roots.size(); dword++) {
 				plan.handle->SetArg(dword, plan.key);
 			}
-			for (const auto index: plan.memory) {
-				m_program.memory_info[index].planning_only = true;
+			if (plan.reads[0] != nullptr) {
+				for (const auto index: plan.memory)
+					m_program.memory_info[index].planning_only = true;
 			}
 		}
 		m_program.descriptor_sources         = std::move(m_sources);
@@ -762,7 +763,7 @@ private:
 				const auto& b = *descriptor.indirect_image;
 				if (a.material_source != b.material_source || a.table_source != b.table_source ||
 				    a.selector_stride != b.selector_stride || a.selector_offset != b.selector_offset ||
-				    a.table_offset != b.table_offset ||
+				    a.table_offset != b.table_offset || a.sources != b.sources ||
 				    !EquivalentValue(m_program, a.key_count, b.key_count) ||
 				    a.selector_mask.IsEmpty() != b.selector_mask.IsEmpty() ||
 				    (!a.selector_mask.IsEmpty() &&
@@ -1474,6 +1475,152 @@ private:
 		return true;
 	}
 
+	uint32_t SelectorMaximum(Value value) const {
+		value = value.Resolve();
+		if (value.IsImmediate() && value.GetType() == Type::U32) return value.U32();
+		const auto* inst = value.TryInstruction();
+		if (inst == nullptr) return UINT32_MAX;
+		if (inst->GetOpcode() == ValueOpcode::FindILsb32)
+			return NonzeroOnEntry(inst->Arg(0), inst->Parent()) ? 31u : UINT32_MAX;
+		if (inst->GetOpcode() == ValueOpcode::UMin32)
+			return std::min(SelectorMaximum(inst->Arg(0)), SelectorMaximum(inst->Arg(1)));
+		uint32_t shift;
+		if (inst->GetOpcode() == ValueOpcode::ShiftLeftLogical32 &&
+		    ImmediateU32(inst->Arg(1), shift) && shift < 32u) {
+			const auto maximum = uint64_t {SelectorMaximum(inst->Arg(0))} << shift;
+			if (maximum <= UINT32_MAX) return static_cast<uint32_t>(maximum);
+		}
+		return UINT32_MAX;
+	}
+
+	bool ImpossibleSwitchEdge(const Block* from, const Block* to) const {
+		const auto from_it = std::ranges::find(m_program.blocks, from);
+		const auto to_it = std::ranges::find(m_program.blocks, to);
+		if (from_it == m_program.blocks.end() || to_it == m_program.blocks.end() ||
+		    m_program.block_info.size() != m_program.blocks.size()) return false;
+		const auto& info = m_program.block_info[from_it - m_program.blocks.begin()];
+		const auto& term = info.terminator;
+		if (term.kind != CFG::TerminatorKind::IndirectBranch ||
+		    term.indirect_selector_code == UINT32_MAX ||
+		    term.indirect_selector_values.empty() ||
+		    term.indirect_selector_values.size() != term.indirect_selector_targets.size()) return false;
+		const auto target = m_program.block_info[to_it - m_program.blocks.begin()].id;
+		const auto maximum = SelectorMaximum(info.indirect_target);
+		bool found = false;
+		for (size_t i = 0; i < term.indirect_selector_values.size(); ++i) {
+			if (term.indirect_selector_targets[i] != target) continue;
+			if (term.indirect_selector_values[i] <= maximum) return false;
+			found = true;
+		}
+		return found;
+	}
+
+	bool TryMakeFiniteImage(Inst& handle, IndirectImagePlan& plan) {
+		if (handle.GetOpcode() != ValueOpcode::GetImageResource || handle.NumArgs() != 8u)
+			return false;
+		if (std::ranges::any_of(handle.Uses(), [](const Use& use) {
+			const auto op = use.user->GetOpcode();
+			return op != ValueOpcode::ImageSampleRaw && op != ValueOpcode::ImageGatherRaw;
+		})) return false;
+		bool has_phi = false;
+		for (size_t word = 0; word < handle.NumArgs(); ++word) has_phi |= handle.Arg(word).Resolve().IsPhi();
+		if (!has_phi) return false;
+		// Normalize the eight synchronized descriptor words to one GPU ordinal.
+		// Build the complete graph before changing IR so an unsupported leaf is transactional.
+		struct Choice {
+			DescriptorSource descriptor;
+			const Inst* branch = nullptr;
+			std::vector<uint32_t> children;
+			Value key;
+		};
+		std::vector<Choice> choices;
+		const auto visit = [&](const auto& self, DescriptorSource descriptor) -> uint32_t {
+			for (auto& word: descriptor.dwords) word = word.Resolve();
+			for (uint32_t i = 0; i < choices.size(); ++i)
+				if (choices[i].descriptor.dwords == descriptor.dwords) return i;
+			const auto index = static_cast<uint32_t>(choices.size());
+			choices.push_back({descriptor});
+			uint32_t bad = 0;
+			if (ValidateSource(descriptor, bad)) return index;
+			const auto* branch = descriptor.dwords[bad].TryInstruction();
+			if (branch == nullptr || branch->Parent() == nullptr ||
+			    branch->GetOpcode() != ValueOpcode::Phi ||
+			    branch->NumPhiBlocks() != branch->NumArgs()) return UINT32_MAX;
+			choices[index].branch = branch;
+			const auto count = branch->NumArgs();
+			for (uint32_t arm = 0; arm < count; ++arm) {
+				// A nonzero bit scan cannot choose its zero-input switch sentinel.
+				// Preserve the Phi edge; its ordinal is never observed at runtime.
+				if (ImpossibleSwitchEdge(branch->PhiBlock(arm), branch->Parent())) {
+					choices[index].children.push_back(UINT32_MAX);
+					continue;
+				}
+				auto child = descriptor;
+				for (uint32_t word = 0; word < child.dword_count; ++word) {
+					const auto* selected = descriptor.dwords[word].TryInstruction();
+					if (selected == nullptr || selected->GetOpcode() != branch->GetOpcode() ||
+					    selected->Parent() != branch->Parent()) {
+						if (!ValidateRuntimeValue(m_program, descriptor.dwords[word])) return UINT32_MAX;
+						continue;
+					}
+					if (selected->NumArgs() != count || selected->NumPhiBlocks() != count)
+						return UINT32_MAX;
+					uint32_t incoming = 0;
+					while (incoming < count && selected->PhiBlock(incoming) != branch->PhiBlock(arm))
+						++incoming;
+					if (incoming == count) return UINT32_MAX;
+					child.dwords[word] = selected->Arg(incoming);
+				}
+				const auto next = self(self, child);
+				if (next == UINT32_MAX) return UINT32_MAX;
+				choices[index].children.push_back(next);
+			}
+			return index;
+		};
+		DescriptorSource root;
+		root.dword_count = 8u;
+		for (uint32_t word = 0; word < root.dword_count; ++word) root.dwords[word] = handle.Arg(word);
+		if (visit(visit, root) == UINT32_MAX || choices.front().branch == nullptr) return false;
+		DescriptorSource image_source;
+		image_source.dword_count = 8u;
+		image_source.dwords.fill(Value(0u));
+		image_source.indirect_image.emplace();
+		auto& sources = image_source.indirect_image->sources;
+		for (auto& choice: choices) {
+			if (choice.branch != nullptr) continue;
+			const auto source = InternSource(choice.descriptor);
+			auto found = std::ranges::find(sources, source);
+			choice.key = Value(static_cast<uint32_t>(found - sources.begin()));
+			if (found == sources.end()) sources.push_back(source);
+		}
+		if (sources.empty()) return false;
+		for (auto& choice: choices) {
+			if (choice.branch == nullptr) continue;
+			auto* block = choice.branch->Parent();
+			const auto where = std::ranges::find_if(block->Instructions(), [&](const Inst& inst) {
+				return &inst == choice.branch;
+			});
+			auto& key = *block->PrependNewInst(where, choice.branch->GetOpcode());
+			key.SetFlags(Type::U32);
+			choice.key = Value(&key);
+		}
+		for (const auto& choice: choices) {
+			if (choice.branch == nullptr) continue;
+			auto* key = choice.key.Instruction();
+			for (uint32_t arm = 0; arm < choice.children.size(); ++arm) {
+				const auto child = choice.children[arm];
+				const auto value = child == UINT32_MAX ? Value(0u) : choices[child].key;
+				key->AddPhiOperand(choice.branch->PhiBlock(arm), value);
+			}
+		}
+		plan.handle = &handle;
+		plan.source = InternSource(image_source);
+		plan.key = choices.front().key;
+		plan.roots = image_source.dwords;
+		plan.reads.fill(nullptr);
+		return true;
+	}
+
 	const IndirectImagePlan* FindIndirectImage(const Inst& handle) const {
 		const auto found =
 		    std::find_if(m_indirect_images.begin(), m_indirect_images.end(),
@@ -1486,7 +1633,8 @@ private:
 	bool IsIndirectPlanningMemory(uint32_t index) const {
 		return std::any_of(m_indirect_images.begin(), m_indirect_images.end(),
 		                   [&](const IndirectImagePlan& plan) {
-			return std::ranges::find(plan.memory, index) != plan.memory.end();
+			return plan.reads[0] != nullptr &&
+			       std::ranges::find(plan.memory, index) != plan.memory.end();
 		});
 	}
 
@@ -1502,7 +1650,7 @@ private:
 					continue;
 				}
 				IndirectImagePlan plan;
-				if (TryMakeIndirectImage(*handle, plan)) {
+				if (TryMakeIndirectImage(*handle, plan) || TryMakeFiniteImage(*handle, plan)) {
 					m_indirect_images.push_back(std::move(plan));
 				}
 			}

tests/ResourceMaterializationTests.cpp

@@ -278,6 +278,101 @@ void TestFailedMaterializationRejectsStage() {
         "missing runtime user data did not reject the cached stage");
 }
 
+void TestFiniteImageRefreshReusesScalarReads() {
+  using namespace Libs::Graphics::ShaderRecompiler::IR;
+  Program program;
+  program.stage = Libs::Graphics::ShaderType::Compute;
+  program.srt_plan_complete = true;
+  program.resource_tracking_complete = true;
+  auto &block = AddValueBlock(program);
+  program.memory_info.push_back({.kind = ResourceKind::ScalarAddress});
+  auto &handle = block.AppendNewInst(ValueOpcode::GetAddressResource,
+                                     {Value(0x1000u), Value(0u)});
+  auto &srt = block.AppendNewInst(ValueOpcode::GetSrtResource);
+  for (uint32_t index = 0; index < 3; ++index) {
+    auto &read = block.AppendNewInst(ValueOpcode::LoadAddressU32,
+        {Value(&handle), Value(index * 4u), Value(0u), Value(true)});
+    read.SetFlags(MemoryFlags{.index = 0});
+    program.srt_reads.push_back({Value(&read), index});
+    auto &flat = block.AppendNewInst(ValueOpcode::ReadConst,
+                                     {Value(&srt), Value(index)});
+    DescriptorSource source;
+    source.dword_count = 8;
+    source.dwords.fill(Value(0u));
+    source.dwords[0] = Value(&flat);
+    source.dwords[1] = Value(static_cast<uint32_t>(
+        Libs::Graphics::Prospero::BufferFormat::k32_32_32_32Float) << 20u);
+    source.dwords[3] = Value(Libs::Graphics::DstSel(4, 5, 6, 7) |
+        (static_cast<uint32_t>(Libs::Graphics::Prospero::ImageType::kColor2D) << 28u));
+    program.descriptor_sources.push_back(source);
+  }
+  DescriptorSource root;
+  root.dword_count = 8;
+  root.dwords.fill(Value(0u));
+  root.indirect_image.emplace().sources = {0, 1, 2, 1};
+  program.descriptor_sources.push_back(root);
+  program.info.images.push_back({
+      .source = 3,
+      .resource_class = ImageResourceClass::Sampled,
+      .numeric_class = Libs::Graphics::Prospero::TextureNumericClass::Float,
+      .dimension = Libs::Graphics::ShaderRecompiler::Decoder::ImageDimension::Dim2D});
+  auto plan = ExtractResourcePlan(program);
+  struct Reads {
+    std::array<uint32_t, 3> words{0x100u, 0x200u, 0x200u};
+    std::array<uint32_t, 3> counts{};
+    uint32_t ordinary = 0;
+  } reads;
+  const SrtRuntime runtime{
+      .read_memory = +[](void *data, uint64_t, std::span<uint32_t>) {
+        ++static_cast<Reads *>(data)->ordinary;
+        return false;
+      },
+      .userdata = &reads,
+      .read_specialization_memory = +[](void *data, uint64_t address,
+                                        std::span<uint32_t> words) {
+        if (words.size() != 1 || address < 0x1000u || address >= 0x100cu ||
+            (address & 3u) != 0) return false;
+        auto &reads = *static_cast<Reads *>(data);
+        const auto index = (address - 0x1000u) / 4u;
+        ++reads.counts[index];
+        words[0] = reads.words[index];
+        return true;
+      }};
+  ResourceSnapshot snapshot;
+  ResourceSpecialization specialization;
+  const auto capacities = [&] {
+    return std::array{snapshot.images.capacity(), snapshot.flattened_srt.capacity(),
+                      snapshot.specialization_reads.capacity(), specialization.images.capacity()};
+  };
+  const auto check_mapping = [&](std::array<uint32_t, 4> ordinals) {
+    const auto offset = specialization.images[0].indirect_mapping_offset;
+    Check(snapshot.images.size() == 2 && snapshot.flattened_srt[offset] == 4,
+          "finite image candidates were not deduplicated");
+    for (uint32_t key = 0; key < ordinals.size(); ++key) {
+      Check(snapshot.flattened_srt[offset + 1u + key * 2u] == key &&
+                snapshot.flattened_srt[offset + 2u + key * 2u] == ordinals[key],
+            "finite image selector mapping is stale or incorrect");
+    }
+  };
+  Check(MaterializeResources(plan, runtime, snapshot, specialization),
+        "finite image materialization failed");
+  Check(reads.ordinary == 0 && reads.counts == std::array<uint32_t, 3>{1, 1, 1} &&
+            snapshot.specialization_reads.size() == 3,
+        "finite image candidates repeated scalar reads or bypassed clean provenance");
+  check_mapping({0, 1, 1, 1});
+  const auto warm_capacities = capacities();
+  reads.words = {0x300u, 0x300u, 0x400u};
+  Check(MaterializeResources(plan, runtime, snapshot, specialization),
+        "finite image refresh failed after descriptor changes");
+  Check(reads.ordinary == 0 && reads.counts == std::array<uint32_t, 3>{2, 2, 2} &&
+            snapshot.specialization_reads.size() == 3 &&
+            snapshot.images[0].dwords[0] == 0x300u && snapshot.images[1].dwords[0] == 0x400u,
+        "finite image refresh retained old scalar values or repeated reads");
+  check_mapping({0, 0, 1, 0});
+  Check(capacities() == warm_capacities,
+        "finite image refresh grew reusable resource storage after warmup");
+}
+
 void TestMixedSamplerDuplicatesTheCorrectSnapshot() {
   using namespace Libs::Graphics::ShaderRecompiler::IR;
   auto plan = MixedSamplerPlan();
@@ -314,6 +409,7 @@ int main() {
   TestUnbasedFlatCacheHitMaterializes();
   TestWrittenDescriptorUsesStrictReaderOnce();
   TestFailedMaterializationRejectsStage();
+  TestFiniteImageRefreshReusesScalarReads();
   TestMixedSamplerDuplicatesTheCorrectSnapshot();
   std::puts("ResourceMaterializationTests: all cases passed");
   return 0;

tests/ResourceTrackingTests.cpp

@@ -2488,6 +2488,132 @@ void TestConditionalSamplerPhi() {
   }
 }
 
+void TestFiniteImagePhiCycle() {
+  Fixture fixture;
+  auto *entry = fixture.block;
+  auto *header = fixture.AddBlock();
+  auto *reload = fixture.AddBlock();
+  auto *merge = fixture.AddBlock();
+  entry->AddBranch(header);
+  header->AddBranch(reload);
+  header->AddBranch(merge);
+  reload->AddBranch(merge);
+  merge->AddBranch(header);
+  std::array<Value, 8> words;
+  for (uint32_t word = 0; word < words.size(); ++word) {
+    auto &loop = header->AppendNewInst(ValueOpcode::Phi, {}, uint64_t(Type::U32));
+    auto &choice = merge->AppendNewInst(ValueOpcode::Phi, {}, uint64_t(Type::U32));
+    loop.AddPhiOperand(entry, fixture.UserData(word));
+    loop.AddPhiOperand(merge, Value(&choice));
+    // Incoming order is independent for each descriptor DWORD.
+    if (word & 1u) {
+      choice.AddPhiOperand(reload, fixture.UserData(word + 8));
+      choice.AddPhiOperand(header, Value(&loop));
+    } else {
+      choice.AddPhiOperand(header, Value(&loop));
+      choice.AddPhiOperand(reload, fixture.UserData(word + 8));
+    }
+    words[word] = Value(&choice);
+  }
+  fixture.block = merge;
+  const auto image = fixture.Image(words);
+  const auto sampler = fixture.Sampler({Value(0u), Value(0u), Value(0u), Value(0u)});
+  MemoryInfo memory;
+  memory.kind = ResourceKind::Image;
+  memory.image_dimension = Decoder::ImageDimension::Dim2D;
+  fixture.Emit(ValueOpcode::ImageSampleRaw, {image, sampler, fixture.ImageAddress()},
+               fixture.AddMemory(memory, 4));
+  fixture.PlanAndTrack();
+  const auto source = fixture.program.info.images[0].source;
+  const auto &finite = fixture.program.descriptor_sources[source].indirect_image;
+  Check(finite && finite->sources.size() == 2,
+        "cyclic image selection did not retain two complete descriptor candidates");
+  const auto *key = image.Instruction()->Arg(0).Instruction();
+  Check(key->GetOpcode() == ValueOpcode::Phi && key->Parent() == merge,
+        "finite image key lost its original merge block");
+  const auto *loop = key->Arg(0).Instruction();
+  Check(loop->GetOpcode() == ValueOpcode::Phi && loop->Parent() == header &&
+            loop->Arg(1).Resolve() == Value(const_cast<Inst *>(key)) &&
+            loop->Arg(0).U32() == 0 && key->Arg(1).U32() == 1,
+        "finite image key did not preserve the loop-carried selection");
+  std::array<uint32_t, 16> data;
+  for (uint32_t i = 0; i < data.size(); ++i) data[i] = 100u + i;
+  SrtWalker walker(fixture.program, SrtRuntime{.user_data = data});
+  for (uint32_t candidate = 0; candidate < 2; ++candidate) {
+    DescriptorValue descriptor;
+    Check(walker.EvaluateDescriptor(finite->sources[candidate], descriptor),
+          "finite image candidate is not host-readable");
+    for (uint32_t word = 0; word < 8; ++word)
+      Check(descriptor.dwords[word] == data[candidate * 8 + word],
+            "finite image selection mixed descriptor DWORDs across predecessors");
+  }
+}
+
+void TestFiniteImageBitScanSentinel() {
+  namespace CFG = Libs::Graphics::ShaderRecompiler::CFG;
+  for (const bool nonzero : {false, true}) {
+    Fixture fixture;
+    auto *entry = fixture.block;
+    auto *dispatch = fixture.AddBlock();
+    auto *load = fixture.AddBlock();
+    auto *merge = fixture.AddBlock();
+    auto *exit = fixture.AddBlock();
+    entry->AddBranch(dispatch);
+    entry->AddBranch(exit);
+    dispatch->AddBranch(load);
+    dispatch->AddBranch(merge);
+    load->AddBranch(merge);
+    const auto mask = fixture.Emit(ValueOpcode::GetBuiltin,
+        {Value(uint32_t(StageInputKind::LocalInvocationIndex)), Value(0u)});
+    const auto condition = fixture.Emit(nonzero ? ValueOpcode::INotEqual32 : ValueOpcode::IEqual32,
+                                        {mask, Value(0u)});
+    auto &guard = fixture.program.block_info[0];
+    guard.condition = condition;
+    guard.terminator.kind = CFG::TerminatorKind::ConditionalBranch;
+    guard.terminator.true_block = 1;
+    guard.terminator.false_block = 4;
+    fixture.block = dispatch;
+    const auto first = fixture.Emit(ValueOpcode::FindILsb32, {mask});
+    const auto minimum = fixture.Emit(ValueOpcode::UMin32, {first, Value(32u)});
+    const auto selector = fixture.Emit(ValueOpcode::ShiftLeftLogical32, {minimum, Value(2u)});
+    fixture.Emit(ValueOpcode::ReferenceU32, {selector});
+    auto &table = fixture.program.block_info[1];
+    table.indirect_target = selector;
+    table.terminator.kind = CFG::TerminatorKind::IndirectBranch;
+    table.terminator.indirect_selector_code = 0;
+    table.terminator.indirect_selector_values = {0u, 128u};
+    table.terminator.indirect_selector_targets = {2u, 3u};
+    std::array<Value, 8> words;
+    for (uint32_t word = 0; word < words.size(); ++word) {
+      auto &phi = merge->AppendNewInst(ValueOpcode::Phi, {}, uint64_t(Type::U32));
+      phi.AddPhiOperand(dispatch, mask);
+      phi.AddPhiOperand(load, Value(100u + word));
+      words[word] = Value(&phi);
+    }
+    fixture.block = merge;
+    const auto image = fixture.Image(words);
+    const auto sampler = fixture.Sampler({Value(0u), Value(0u), Value(0u), Value(0u)});
+    MemoryInfo memory;
+    memory.kind = ResourceKind::Image;
+    memory.image_dimension = Decoder::ImageDimension::Dim2D;
+    fixture.Emit(ValueOpcode::ImageSampleRaw, {image, sampler, fixture.ImageAddress()},
+                 fixture.AddMemory(memory, 4));
+    if (!nonzero) {
+      CheckFatal([&] { fixture.PlanAndTrack(); }, "not a valid runtime value",
+                 "zero bit scan silently accepted a GPU-valued descriptor sentinel");
+      Check(fixture.program.descriptor_sources.empty() && image.Instruction()->Arg(0) == words[0],
+            "failed finite descriptor analysis partially mutated the resource plan");
+      continue;
+    }
+    fixture.PlanAndTrack();
+    const auto source = fixture.program.info.images[0].source;
+    const auto &finite = fixture.program.descriptor_sources[source].indirect_image;
+    Check(finite && finite->sources.size() == 1 &&
+              image.Instruction()->Arg(0).Instruction()->NumPhiBlocks() == 2,
+          "nonzero bit scan retained its impossible sentinel or removed a Phi edge");
+  }
+}
+
 void TestLoopCycleEnteredThroughRuntimeValue() {
   Fixture fixture;
   auto *entry = fixture.block;
@@ -3292,6 +3418,8 @@ int main() {
     Run("dynamic SRT", TestDynamicSrtReadRemainsExplicit);
     Run("phi validation", TestPhiValidation);
     Run("conditional sampler phi", TestConditionalSamplerPhi);
+    Run("finite image phi cycle", TestFiniteImagePhiCycle);
+    Run("finite image bit scan sentinel", TestFiniteImageBitScanSentinel);
     Run("runtime-rooted loop", TestLoopCycleEnteredThroughRuntimeValue);
     Run("invariant loop phi", TestInvariantLoopPhi);
     Run("DMA address materialization", TestDmaAddressMaterialization);