From 0f7d11254564dabea0ec7067ffd4c1b6b48c3618 Mon Sep 17 00:00:00 2001
From: nmzik <Nmzik@mail.ru>
Date: Wed, 21 Oct 2026 23:26:07 +0200
Subject: [PATCH] shader: emit constant-true guarded blocks inline and fold
 immediate constant-buffer indices

---
 .../recompiler/backend/spirv/spirvEmitterInternal.h      | 5 +++++
 .../recompiler/backend/spirv/spirvEmitterMemory.cpp      | 9 ++++++---
 tests/shaderCfgTests.cpp                                 | 1 +
 3 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/graphics/shader/recompiler/backend/spirv/spirvEmitterInternal.h b/src/graphics/shader/recompiler/backend/spirv/spirvEmitterInternal.h
index 67444ef9c..bc6b7b45e 100644
--- a/src/graphics/shader/recompiler/backend/spirv/spirvEmitterInternal.h
+++ b/src/graphics/shader/recompiler/backend/spirv/spirvEmitterInternal.h
@@ -580,6 +580,10 @@ auto EmitIndexSwitch(EmitterState& state, uint32_t index, uint32_t count,
 
 template <typename Fn>
 void EmitIfCondition(EmitterState& state, uint32_t condition, Fn&& fn) {
+	if (condition == ConstantBool(state, true)) {
+		fn();
+		return;
+	}
 	const auto then_label  = state.builder.AllocateId();
 	const auto merge_label = state.builder.AllocateId();
 	state.builder.AddFunction(spv::OpSelectionMerge, merge_label, spv::SelectionControlMaskNone);
@@ -593,6 +597,7 @@ void EmitIfCondition(EmitterState& state, uint32_t condition, Fn&& fn) {
 template <typename Fn>
 uint32_t EmitValueOrDefaultIfCondition(EmitterState& state, uint32_t condition, uint32_t type,
                                        uint32_t default_value, Fn&& fn) {
+	if (condition == ConstantBool(state, true)) return fn();
 	const auto then_label  = state.builder.AllocateId();
 	const auto header     = state.current_label;
 	const auto merge_label = state.builder.AllocateId();
diff --git a/src/graphics/shader/recompiler/backend/spirv/spirvEmitterMemory.cpp b/src/graphics/shader/recompiler/backend/spirv/spirvEmitterMemory.cpp
index 6159e56ed..71bd27c81 100644
--- a/src/graphics/shader/recompiler/backend/spirv/spirvEmitterMemory.cpp
+++ b/src/graphics/shader/recompiler/backend/spirv/spirvEmitterMemory.cpp
@@ -1605,9 +1605,12 @@ void EmitReadConstBuffer(ValueEmitContext& ctx, const IR::Inst& inst) {
 	}
 	auto& state        = ctx.state;
 	mem.kind           = IR::ResourceKind::ScalarBuffer;
-	auto index = Binary(state, spv::OpShiftRightLogical, TypeU32(state), ctx.Arg(inst, 1),
-	                    ConstantU32(state, 2));
-	if (mem.offset >= 4u) {
+	const auto offset = inst.Arg(1).Resolve();
+	auto       index  = offset.IsImmediate()
+	                        ? ConstantU32(state, (offset.U32() >> 2u) + (mem.offset >> 2u))
+	                        : Binary(state, spv::OpShiftRightLogical, TypeU32(state),
+	                                 ctx.Arg(inst, 1), ConstantU32(state, 2));
+	if (!offset.IsImmediate() && mem.offset >= 4u) {
 		index = Binary(state, spv::OpIAdd, TypeU32(state), index, ConstantU32(state, mem.offset >> 2u));
 	}
 	const auto access    = PrepareMemoryResourceAccess(state, mem);
diff --git a/tests/shaderCfgTests.cpp b/tests/shaderCfgTests.cpp
index 965f182ea..09b0be1d9 100644
--- a/tests/shaderCfgTests.cpp
+++ b/tests/shaderCfgTests.cpp
@@ -10532,6 +10532,7 @@ void TestComputeDispatchWaveSize() {
 
 void TestNewShaderRecompilerBufferLoadsGuardedByExec() {
   const uint32_t shader[] = {
+      EncodeVopc(0xd4, 0 + 256, 1), // v_cmpx_gt_u32 v0, v1
       EncodeMubuf0(0x0c),
       EncodeMubuf1(0, 0, 1), // buffer_load_dword
                              // v0