From 11465a5e3caf17f4f82ab1e9faec69dd3b608272 Mon Sep 17 00:00:00 2001
From: nmzik <Nmzik@mail.ru>
Date: Thu, 22 Oct 2026 00:44:43 +0200
Subject: [PATCH] shader: drop the large-input select before sin and cos since
 fract already returns zero

---
 .../backend/spirv/spirvEmitterAluHelpers.cpp  | 33 +++++------------
 tests/ShaderRecompilerComputeTests.cpp        | 35 +++++++++++--------
 2 files changed, 29 insertions(+), 39 deletions(-)

diff --git a/src/graphics/shader/recompiler/backend/spirv/spirvEmitterAluHelpers.cpp b/src/graphics/shader/recompiler/backend/spirv/spirvEmitterAluHelpers.cpp
index c8a5e9b0f..d2120d8ed 100644
--- a/src/graphics/shader/recompiler/backend/spirv/spirvEmitterAluHelpers.cpp
+++ b/src/graphics/shader/recompiler/backend/spirv/spirvEmitterAluHelpers.cpp
@@ -162,34 +162,19 @@ uint32_t EmitFlushF32DenormToSignedZero(EmitterState& state, uint32_t value) {
 }
 
 uint32_t EmitTrigCycleF32(EmitterState& state, uint32_t src, bool preserve_signed_zero) {
-	const auto fract        = state.builder.AllocateId();
-	const auto bits         = state.builder.AllocateId();
-	const auto abs_bits     = state.builder.AllocateId();
-	const auto large        = state.builder.AllocateId();
-	const auto finite       = state.builder.AllocateId();
-	const auto large_finite = state.builder.AllocateId();
-	const auto reduced      = state.builder.AllocateId();
+	// Finite values of magnitude 2^23 and above are integers, so fract already gives them +0.
+	const auto fract = state.builder.AllocateId();
 	state.builder.AddFunction(spv::OpExtInst, TypeF32(state), fract, GlslStd450(state),
 	                          GLSLstd450Fract, src);
-	state.builder.AddFunction(spv::OpBitcast, TypeU32(state), bits, src);
-	state.builder.AddFunction(spv::OpBitwiseAnd, TypeU32(state), abs_bits, bits,
-	                          ConstantU32(state, 0x7fffffffu));
-	state.builder.AddFunction(spv::OpUGreaterThanEqual, TypeBool(state), large, abs_bits,
-	                          ConstantU32(state, 0x4b000000u));
-	state.builder.AddFunction(spv::OpULessThan, TypeBool(state), finite, abs_bits,
-	                          ConstantU32(state, 0x7f800000u));
-	state.builder.AddFunction(spv::OpLogicalAnd, TypeBool(state), large_finite, large, finite);
-	state.builder.AddFunction(spv::OpSelect, TypeF32(state), reduced, large_finite,
-	                          ConstantF32(state, 0), fract);
 	if (!preserve_signed_zero) {
-		return reduced;
+		return fract;
 	}
-	const auto zero = state.builder.AllocateId();
-	const auto ret  = state.builder.AllocateId();
-	state.builder.AddFunction(spv::OpIEqual, TypeBool(state), zero, abs_bits,
-	                          ConstantU32(state, 0));
-	state.builder.AddFunction(spv::OpSelect, TypeF32(state), ret, zero, src, reduced);
-	return ret;
+	const auto abs_bits = Binary(state, spv::OpBitwiseAnd, TypeU32(state),
+	                             Unary(state, spv::OpBitcast, TypeU32(state), src),
+	                             ConstantU32(state, 0x7fffffffu));
+	return Select(state, TypeF32(state),
+	              Binary(state, spv::OpIEqual, TypeBool(state), abs_bits, ConstantU32(state, 0)),
+	              src, fract);
 }
 
 uint32_t EmitF16BitsToF32(EmitterState& state, uint32_t bits) {
diff --git a/tests/ShaderRecompilerComputeTests.cpp b/tests/ShaderRecompilerComputeTests.cpp
index fb7ffefd9..1febaa64c 100644
--- a/tests/ShaderRecompilerComputeTests.cpp
+++ b/tests/ShaderRecompilerComputeTests.cpp
@@ -29230,23 +29230,28 @@ TestCase VectorRcpIflagF32IntegerReciprocal() {
   return test;
 }
 
+// Runtime inputs keep the driver from folding; finite values from 2^23 up are whole periods.
 TestCase VectorSinCosMaxFiniteSpecialCases() {
   using O = ShaderOpcode;
-
-  std::vector<u32> code;
-  AppendVMovLiteral(&code, 0, 0xff7fffffu);
-  code.push_back(EncodeVop1(0x35, 1, Vgpr(0)));
-  code.push_back(EncodeVop1(0x36, 2, Vgpr(0)));
-  AppendStoreVgpr(&code, 1, 0);
-  AppendStoreVgpr(&code, 2, 1);
-  AppendEnd(&code);
-
-  return {"VectorSinCosMaxFiniteSpecialCases",
-          code,
-          {},
-          {0x00000000u, 0x3f800000u},
-          {O::V_MOV_B32, O::V_SIN_F32, O::V_COS_F32, O::BUFFER_STORE_DWORD,
-           O::S_ENDPGM}};
+  constexpr u32 inputs[] = {0xff7fffffu, 0x7f7fffffu, 0x4b000001u, 0xcb800000u};
+  TestCase test;
+  test.name = "VectorSinCosMaxFiniteSpecialCases";
+  test.initial.assign(std::begin(inputs), std::end(inputs));
+  test.expected = test.initial;
+  for (u32 i = 0; i < std::size(inputs); i++) {
+    AppendVMovU32(&test.code, 30, i * 4u);
+    AppendBufferLoadDword(&test.code, 0, 30);
+    test.code.push_back(EncodeVop1(0x35, 1, Vgpr(0)));
+    test.code.push_back(EncodeVop1(0x36, 2, Vgpr(0)));
+    AppendStoreVgpr(&test.code, 1, u32(test.expected.size()));
+    AppendStoreVgpr(&test.code, 2, u32(test.expected.size() + 1));
+    test.expected.insert(test.expected.end(), {0x00000000u, 0x3f800000u});
+  }
+  AppendEnd(&test.code);
+  test.initial.resize(test.expected.size());
+  test.opcodes = {O::V_MOV_B32, O::BUFFER_LOAD_DWORD, O::V_SIN_F32, O::V_COS_F32,
+                  O::BUFFER_STORE_DWORD, O::S_ENDPGM};
+  return test;
 }
 
 TestCase VectorCompareF32ExposureGuard() {