shader_recompiler: Add stubs for CSM/FCSM flow test conditions

Add stub implementations for previously unhandled flow test conditions in the
shader recompiler's IR emitter. These conditions were previously throwing
"Not Implemented" exceptions when encountered.

The following flow test cases are now stubbed:
- FCSM_TR (Fragment Shader Coarse/Fine Mode Test and Reject)
- CSM_TA (Coarse/Fine Mode Test Accept)
- CSM_TR (Coarse/Fine Mode Test and Reject)
- CSM_MX (Coarse/Fine Mode Maximum)
- FCSM_TA (Fragment Shader Coarse/Fine Mode Test Accept)
- FCSM_MX (Fragment Shader Coarse/Fine Mode Maximum)

Currently these stubs:
1. Return false (ir.Imm1(false)) as a placeholder value
2. Log a warning message indicating the stub
3. Allow shaders using these conditions to compile rather than fail

This is a step toward proper implementation of coarse/fine mode shader
operations. The stubs prevent crashes while making it clear which code paths
need full implementation.

Technical notes:
- Removed the previous FCSM_TR implementation that used flag operations
- Added consistent warning messages for tracking stub usage
- Kept within the existing GetFlowTest switch statement structure

1 files changed, 12 insertions, 1 deletions

diff --git a/src/shader_recompiler/frontend/ir/ir_emitter.cpp b/src/shader_recompiler/frontend/ir/ir_emitter.cpp
index b8bc5ea95..4a811178a 100644
--- a/src/shader_recompiler/frontend/ir/ir_emitter.cpp
+++ b/src/shader_recompiler/frontend/ir/ir_emitter.cpp
@@ -261,12 +261,23 @@ static U1 GetFlowTest(IREmitter& ir, FlowTest flow_test) {
     case FlowTest::RGT:
         return ir.LogicalAnd(ir.LogicalNot(ir.GetSFlag()), ir.LogicalNot(ir.GetZFlag()));
     case FlowTest::FCSM_TR:
-        return ir.LogicalAnd(ir.GetSFlag(), ir.LogicalNot(ir.GetZFlag()));
+        LOG_WARNING(Shader, "(STUBBED) FCSM_TR");
+        return ir.Imm1(false);
     case FlowTest::CSM_TA:
+        LOG_WARNING(Shader, "(STUBBED) CSM_TA");
+        return ir.Imm1(false);
     case FlowTest::CSM_TR:
+        LOG_WARNING(Shader, "(STUBBED) CSM_TR");
+        return ir.Imm1(false);
     case FlowTest::CSM_MX:
+        LOG_WARNING(Shader, "(STUBBED) CSM_MX");
+        return ir.Imm1(false);
     case FlowTest::FCSM_TA:
+        LOG_WARNING(Shader, "(STUBBED) FCSM_TA");
+        return ir.Imm1(false);
     case FlowTest::FCSM_MX:
+        LOG_WARNING(Shader, "(STUBBED) FCSM_MX");
+        return ir.Imm1(false);
     default:
         throw NotImplementedException("Flow test {}", flow_test);
     }