shader: batch dependent folds to avoid repeated SSA graph walks

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

@@ -51,11 +51,13 @@ public:
 	}
 
 	void QueueUsers(const std::vector<Use>& users) {
-		++generation;
-		affected.clear();
 		for (const auto& use: users) affected.push_back(use.user);
+	}
+
+	void FlushUsers() {
+		++generation;
 		// Pattern folds inspect nested operands even when intermediate operations
-		// stay dynamic. Visit consumers once per change, including cyclic Phi edges.
+		// stay dynamic. Visit their union once per drain, including cyclic Phi edges.
 		for (size_t i = 0; i < affected.size(); ++i) {
 			auto* inst = affected[i];
 			const auto found = locations.find(inst);
@@ -64,6 +66,7 @@ public:
 			Queue(inst);
 			for (const auto& use: inst->Uses()) affected.push_back(use.user);
 		}
+		affected.clear();
 	}
 
 	Block::iterator Prepend(Block& block, Block::iterator before, ValueOpcode opcode,
@@ -977,6 +980,7 @@ void ConstantPropagationPass(const BlockList& blocks, uint32_t wave_size) {
 	std::vector<Use> users;
 	std::vector<Value> operands;
 	const auto drain = [&] {
+		do {
 			for (size_t i = 0; i < worklist.pending.size(); ++i) {
 				auto* inst = worklist.pending[i];
 				auto& location = worklist.locations.at(inst);
@@ -998,6 +1002,8 @@ void ConstantPropagationPass(const BlockList& blocks, uint32_t wave_size) {
 				}
 			}
 			worklist.pending.clear();
+			worklist.FlushUsers();
+		} while (!worklist.pending.empty());
 	};
 	drain();
 	// Normalize retained PHI/select values only after every supported field read has