From 9fbfe7d676790dea160368eda6492e8feb6e2f4a Mon Sep 17 00:00:00 2001
From: ReinUsesLisp <reinuseslisp@airmail.cc>
Date: Mon, 24 May 2021 20:59:49 -0300
Subject: [PATCH] glasm: Fix usage counting on phi nodes

---
 .../backend/glasm/emit_glasm.cpp                 | 12 +++++++++---
 .../backend/glasm/emit_glasm_instructions.h      |  2 +-
 .../backend/glasm/emit_glasm_not_implemented.cpp | 16 ++++++++++++----
 3 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/src/shader_recompiler/backend/glasm/emit_glasm.cpp b/src/shader_recompiler/backend/glasm/emit_glasm.cpp
index 8718cc7ecb..2ce8390592 100644
--- a/src/shader_recompiler/backend/glasm/emit_glasm.cpp
+++ b/src/shader_recompiler/backend/glasm/emit_glasm.cpp
@@ -178,6 +178,10 @@ void EmitInst(EmitContext& ctx, IR::Inst* inst) {
     throw LogicError("Invalid opcode {}", inst->GetOpcode());
 }
 
+bool IsReference(IR::Inst& inst) {
+    return inst.GetOpcode() == IR::Opcode::Reference;
+}
+
 void Precolor(EmitContext& ctx, const IR::Program& program) {
     for (IR::Block* const block : program.blocks) {
         for (IR::Inst& phi : block->Instructions() | std::views::take_while(IR::IsPhi)) {
@@ -194,11 +198,13 @@ void Precolor(EmitContext& ctx, const IR::Program& program) {
             default:
                 throw NotImplementedException("Phi node type {}", phi.Type());
             }
+            // Insert phi moves before references to avoid overwritting them
             const size_t num_args{phi.NumArgs()};
             for (size_t i = 0; i < num_args; ++i) {
-                IR::IREmitter{*phi.PhiBlock(i)}.PhiMove(phi, phi.Arg(i));
+                IR::Block& phi_block{*phi.PhiBlock(i)};
+                auto it{std::find_if_not(phi_block.rbegin(), phi_block.rend(), IsReference).base()};
+                IR::IREmitter{phi_block, it}.PhiMove(phi, phi.Arg(i));
             }
-            // Add reference to the phi node on the phi predecessor to avoid overwritting it
             for (size_t i = 0; i < num_args; ++i) {
                 IR::IREmitter{*phi.PhiBlock(i)}.Reference(IR::Value{&phi});
             }
@@ -237,7 +243,7 @@ void EmitCode(EmitContext& ctx, const IR::Program& program) {
                 }
             } else {
                 ctx.Add("MOV.S.CC RC,{};"
-                        "BRK (EQ.x);"
+                        "BRK(EQ.x);"
                         "ENDREP;",
                         eval(node.data.repeat.cond));
             }
diff --git a/src/shader_recompiler/backend/glasm/emit_glasm_instructions.h b/src/shader_recompiler/backend/glasm/emit_glasm_instructions.h
index 5e038b3329..cc7aa8e20b 100644
--- a/src/shader_recompiler/backend/glasm/emit_glasm_instructions.h
+++ b/src/shader_recompiler/backend/glasm/emit_glasm_instructions.h
@@ -23,7 +23,7 @@ void EmitPhi(EmitContext& ctx, IR::Inst& inst);
 void EmitVoid(EmitContext& ctx);
 void EmitIdentity(EmitContext& ctx, IR::Inst& inst, const IR::Value& value);
 void EmitConditionRef(EmitContext& ctx, IR::Inst& inst, const IR::Value& value);
-void EmitReference(EmitContext&);
+void EmitReference(EmitContext&, const IR::Value& value);
 void EmitPhiMove(EmitContext& ctx, const IR::Value& phi, const IR::Value& value);
 void EmitJoin(EmitContext& ctx);
 void EmitDemoteToHelperInvocation(EmitContext& ctx);
diff --git a/src/shader_recompiler/backend/glasm/emit_glasm_not_implemented.cpp b/src/shader_recompiler/backend/glasm/emit_glasm_not_implemented.cpp
index 756134d025..3d7a3ebb42 100644
--- a/src/shader_recompiler/backend/glasm/emit_glasm_not_implemented.cpp
+++ b/src/shader_recompiler/backend/glasm/emit_glasm_not_implemented.cpp
@@ -17,18 +17,26 @@ namespace Shader::Backend::GLASM {
 
 #define NotImplemented() throw NotImplementedException("GLASM instruction {}", __LINE__)
 
-void EmitPhi(EmitContext&, IR::Inst&) {}
+void EmitPhi(EmitContext& ctx, IR::Inst& inst) {
+    const size_t num_args{inst.NumArgs()};
+    for (size_t i = 0; i < num_args; ++i) {
+        ctx.reg_alloc.Consume(inst.Arg(i));
+    }
+}
 
 void EmitVoid(EmitContext&) {}
 
-void EmitReference(EmitContext&) {}
+void EmitReference(EmitContext& ctx, const IR::Value& value) {
+    ctx.reg_alloc.Consume(value);
+}
 
 void EmitPhiMove(EmitContext& ctx, const IR::Value& phi, const IR::Value& value) {
+    const Register phi_reg{ctx.reg_alloc.Consume(phi)};
+    const Value eval_value{ctx.reg_alloc.Consume(value)};
+
     if (phi == value) {
         return;
     }
-    const Register phi_reg{ctx.reg_alloc.Consume(phi)};
-    const Value eval_value{ctx.reg_alloc.Consume(value)};
     switch (phi.Inst()->Flags<IR::Type>()) {
     case IR::Type::U1:
     case IR::Type::U32: