glasm: Rework control flow introducing a syntax list

This commit regresses VertexA shaders, their transformation pass has to
be adapted to the new control flow.

src/shader_recompiler/ir_opt/constant_propagation_pass.cpp

@@ -353,24 +353,6 @@ IR::Value EvalImmediates(const IR::Inst& inst, Func&& func, std::index_sequence<
     return IR::Value{func(Arg<typename Traits::template ArgType<I>>(inst.Arg(I))...)};
 }
 
-void FoldBranchConditional(IR::Inst& inst) {
-    const IR::U1 cond{inst.Arg(0)};
-    if (cond.IsImmediate()) {
-        // TODO: Convert to Branch
-        return;
-    }
-    const IR::Inst* cond_inst{cond.InstRecursive()};
-    if (cond_inst->GetOpcode() == IR::Opcode::LogicalNot) {
-        const IR::Value true_label{inst.Arg(1)};
-        const IR::Value false_label{inst.Arg(2)};
-        // Remove negation on the conditional (take the parameter out of LogicalNot) and swap
-        // the branches
-        inst.SetArg(0, cond_inst->Arg(0));
-        inst.SetArg(1, false_label);
-        inst.SetArg(2, true_label);
-    }
-}
-
 std::optional<IR::Value> FoldCompositeExtractImpl(IR::Value inst_value, IR::Opcode insert,
                                                   IR::Opcode construct, u32 first_index) {
     IR::Inst* const inst{inst_value.InstRecursive()};
@@ -581,8 +563,6 @@ void ConstantPropagation(IR::Block& block, IR::Inst& inst) {
             return (base & ~(~(~0u << bits) << offset)) | (insert << offset);
         });
         return;
-    case IR::Opcode::BranchConditional:
-        return FoldBranchConditional(inst);
     case IR::Opcode::CompositeExtractF32x2:
         return FoldCompositeExtract(inst, IR::Opcode::CompositeConstructF32x2,
                                     IR::Opcode::CompositeInsertF32x2);

src/shader_recompiler/ir_opt/dual_vertex_pass.cpp

@@ -13,60 +13,16 @@
 
 namespace Shader::Optimization {
 
-void VertexATransformPass(IR::Program& program) {
-    bool replaced_join{};
-    bool eliminated_epilogue{};
-    for (IR::Block* const block : program.post_order_blocks) {
-        for (IR::Inst& inst : block->Instructions()) {
-            switch (inst.GetOpcode()) {
-            case IR::Opcode::Return:
-                inst.ReplaceOpcode(IR::Opcode::Join);
-                replaced_join = true;
-                break;
-            case IR::Opcode::Epilogue:
-                inst.Invalidate();
-                eliminated_epilogue = true;
-                break;
-            default:
-                break;
-            }
-            if (replaced_join && eliminated_epilogue) {
-                return;
-            }
-        }
-    }
+void VertexATransformPass(IR::Program&) {
+    throw NotImplementedException("VertexA pass");
 }
 
-void VertexBTransformPass(IR::Program& program) {
-    for (IR::Block* const block : program.blocks) {
-        for (IR::Inst& inst : block->Instructions()) {
-            if (inst.GetOpcode() == IR::Opcode::Prologue) {
-                return inst.Invalidate();
-            }
-        }
-    }
+void VertexBTransformPass(IR::Program&) {
+    throw NotImplementedException("VertexA pass");
 }
 
-void DualVertexJoinPass(IR::Program& program) {
-    const auto& blocks = program.blocks;
-    const s64 sub_size = static_cast<s64>(blocks.size()) - 1;
-    if (sub_size < 1) {
-        throw LogicError("Dual Vertex Join pass failed, expected atleast 2 blocks");
-    }
-    for (s64 index = 0; index < sub_size; ++index) {
-        IR::Block* const current_block{blocks[index]};
-        IR::Block* const next_block{blocks[index + 1]};
-        for (IR::Inst& inst : current_block->Instructions()) {
-            if (inst.GetOpcode() == IR::Opcode::Join) {
-                IR::IREmitter ir{*current_block, IR::Block::InstructionList::s_iterator_to(inst)};
-                ir.Branch(next_block);
-                inst.Invalidate();
-                // Only 1 join should exist
-                return;
-            }
-        }
-    }
-    throw LogicError("Dual Vertex Join pass failed, no join present");
+void DualVertexJoinPass(IR::Program&) {
+    throw NotImplementedException("VertexA pass");
 }
 
 } // namespace Shader::Optimization

src/shader_recompiler/ir_opt/identity_removal_pass.cpp

@@ -12,7 +12,6 @@ namespace Shader::Optimization {
 
 void IdentityRemovalPass(IR::Program& program) {
     std::vector<IR::Inst*> to_invalidate;
-
     for (IR::Block* const block : program.blocks) {
         for (auto inst = block->begin(); inst != block->end();) {
             const size_t num_args{inst->NumArgs()};

src/shader_recompiler/ir_opt/ssa_rewrite_pass.cpp

@@ -202,7 +202,7 @@ public:
 
                     incomplete_phis[block].insert_or_assign(variable, phi);
                     stack.back().result = IR::Value{&*phi};
-                } else if (const std::span imm_preds{block->ImmediatePredecessors()};
+                } else if (const std::span imm_preds = block->ImmPredecessors();
                            imm_preds.size() == 1) {
                     // Optimize the common case of one predecessor: no phi needed
                     stack.back().pc = Status::SetValue;
@@ -257,7 +257,7 @@ public:
 private:
     template <typename Type>
     IR::Value AddPhiOperands(Type variable, IR::Inst& phi, IR::Block* block) {
-        for (IR::Block* const imm_pred : block->ImmediatePredecessors()) {
+        for (IR::Block* const imm_pred : block->ImmPredecessors()) {
             phi.AddPhiOperand(imm_pred, ReadVariable(variable, imm_pred));
         }
         return TryRemoveTrivialPhi(phi, block, UndefOpcode(variable));