From 740c70f270c4654d3b4cf30dc55d888f45866209 Mon Sep 17 00:00:00 2001
From: "Dr. Chat" <arkolbed@gmail.com>
Date: Tue, 1 Mar 2016 12:52:34 -0600
Subject: [PATCH] Scalar logc, fix log

---
 src/xenia/gpu/spirv_shader_translator.cc | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/src/xenia/gpu/spirv_shader_translator.cc b/src/xenia/gpu/spirv_shader_translator.cc
index a45294415..600e3fe56 100644
--- a/src/xenia/gpu/spirv_shader_translator.cc
+++ b/src/xenia/gpu/spirv_shader_translator.cc
@@ -729,6 +729,7 @@ void SpirvShaderTranslator::ProcessVectorAluInstruction(
     const ParsedAluInstruction& instr) {
   auto& b = *builder_;
 
+  // TODO: If we have identical operands, reuse previous one.
   Id sources[3] = {0};
   Id dest = 0;
   for (size_t i = 0; i < instr.operand_count; i++) {
@@ -899,12 +900,24 @@ void SpirvShaderTranslator::ProcessVectorAluInstruction(
     } break;
 
     case AluVectorOpcode::kMax: {
+      if (sources[0] == sources[1]) {
+        // mov dst, src
+        dest = sources[0];
+        break;
+      }
+
       dest = CreateGlslStd450InstructionCall(spv::NoPrecision, vec4_float_type_,
                                              spv::GLSLstd450::kFMax,
                                              {sources[0], sources[1]});
     } break;
 
     case AluVectorOpcode::kMin: {
+      if (sources[0] == sources[1]) {
+        // mov dst, src
+        dest = sources[0];
+        break;
+      }
+
       dest = CreateGlslStd450InstructionCall(spv::NoPrecision, vec4_float_type_,
                                              spv::GLSLstd450::kFMin,
                                              {sources[0], sources[1]});
@@ -1065,6 +1078,7 @@ void SpirvShaderTranslator::ProcessScalarAluInstruction(
     const ParsedAluInstruction& instr) {
   auto& b = *builder_;
 
+  // TODO: If we have identical operands, reuse previous one.
   Id sources[3] = {0};
   Id dest = 0;
   for (size_t i = 0, x = 0; i < instr.operand_count; i++) {
@@ -1230,10 +1244,17 @@ void SpirvShaderTranslator::ProcessScalarAluInstruction(
     } break;
 
     case AluScalarOpcode::kLogc: {
+      auto t = CreateGlslStd450InstructionCall(
+          spv::NoPrecision, float_type_, spv::GLSLstd450::kLog2, {sources[0]});
+
+      // FIXME: We don't check to see if t == -INF, we just check for INF
+      auto c = b.createUnaryOp(spv::Op::OpIsInf, bool_type_, t);
+      dest = b.createTriOp(spv::Op::OpSelect, float_type_, c,
+                           b.makeFloatConstant(-FLT_MAX), t);
     } break;
 
     case AluScalarOpcode::kLog: {
-      auto log = CreateGlslStd450InstructionCall(
+      dest = CreateGlslStd450InstructionCall(
           spv::NoPrecision, float_type_, spv::GLSLstd450::kLog2, {sources[0]});
     } break;