3 files changed, 85 insertions, 5 deletions

diff --git a/src/shader_recompiler/ir_opt/constant_propagation_pass.cpp b/src/shader_recompiler/ir_opt/constant_propagation_pass.cpp
index f46e55122..ec12c843a 100644
--- a/src/shader_recompiler/ir_opt/constant_propagation_pass.cpp
+++ b/src/shader_recompiler/ir_opt/constant_propagation_pass.cpp
@@ -428,7 +428,7 @@ void FoldFPAdd32(IR::Inst& inst) {
     }
 }
 
-bool FoldDerivateYFromCorrection(IR::Inst& inst) {
+bool FoldDerivativeYFromCorrection(IR::Inst& inst) {
     const IR::Value lhs_value{inst.Arg(0)};
     const IR::Value rhs_value{inst.Arg(1)};
     IR::Inst* const lhs_op{lhs_value.InstRecursive()};
@@ -464,7 +464,7 @@ void FoldFPMul32(IR::Inst& inst) {
     if (lhs_value.IsImmediate() || rhs_value.IsImmediate()) {
         return;
     }
-    if (FoldDerivateYFromCorrection(inst)) {
+    if (FoldDerivativeYFromCorrection(inst)) {
         return;
     }
     IR::Inst* const lhs_op{lhs_value.InstRecursive()};
@@ -699,7 +699,7 @@ void FoldFSwizzleAdd(IR::Block& block, IR::Inst& inst) {
     }
 }
 
-bool FindGradient3DDerivates(std::array<IR::Value, 3>& results, IR::Value coord) {
+bool FindGradient3DDerivatives(std::array<IR::Value, 3>& results, IR::Value coord) {
     if (coord.IsImmediate()) {
         return false;
     }
@@ -834,7 +834,7 @@ void FoldImageSampleImplicitLod(IR::Block& block, IR::Inst& inst) {
     IR::Inst* const inst2 = coords.InstRecursive();
     std::array<std::array<IR::Value, 3>, 3> results_matrix;
     for (size_t i = 0; i < 3; i++) {
-        if (!FindGradient3DDerivates(results_matrix[i], inst2->Arg(i).Resolve())) {
+        if (!FindGradient3DDerivatives(results_matrix[i], inst2->Arg(i).Resolve())) {
             return;
         }
     }
@@ -852,7 +852,7 @@ void FoldImageSampleImplicitLod(IR::Block& block, IR::Inst& inst) {
     IR::Value derivatives_1 = ir.CompositeConstruct(results_matrix[0][1], results_matrix[0][2],
                                                     results_matrix[1][1], results_matrix[1][2]);
     IR::Value derivatives_2 = ir.CompositeConstruct(results_matrix[2][1], results_matrix[2][2]);
-    info.num_derivates.Assign(3);
+    info.num_derivatives.Assign(3);
     IR::Value new_gradient_instruction =
         ir.ImageGradient(handle, new_coords, derivatives_1, derivatives_2, lod_clamp, info);
     IR::Inst* const new_inst = new_gradient_instruction.InstRecursive();
diff --git a/src/shader_recompiler/ir_opt/passes.h b/src/shader_recompiler/ir_opt/passes.h
index 629d18fa1..d4d5285e5 100644
--- a/src/shader_recompiler/ir_opt/passes.h
+++ b/src/shader_recompiler/ir_opt/passes.h
@@ -26,6 +26,7 @@ void SsaRewritePass(IR::Program& program);
 void PositionPass(Environment& env, IR::Program& program);
 void TexturePass(Environment& env, IR::Program& program, const HostTranslateInfo& host_info);
 void LayerPass(IR::Program& program, const HostTranslateInfo& host_info);
+void VendorWorkaroundPass(IR::Program& program);
 void VerificationPass(const IR::Program& program);
 
 // Dual Vertex
diff --git a/src/shader_recompiler/ir_opt/vendor_workaround_pass.cpp b/src/shader_recompiler/ir_opt/vendor_workaround_pass.cpp
new file mode 100644
index 000000000..08c658cb8
--- /dev/null
+++ b/src/shader_recompiler/ir_opt/vendor_workaround_pass.cpp
@@ -0,0 +1,79 @@
+// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "shader_recompiler/frontend/ir/basic_block.h"
+#include "shader_recompiler/frontend/ir/ir_emitter.h"
+#include "shader_recompiler/frontend/ir/value.h"
+#include "shader_recompiler/ir_opt/passes.h"
+
+namespace Shader::Optimization {
+
+namespace {
+void AddingByteSwapsWorkaround(IR::Block& block, IR::Inst& inst) {
+    /*
+     * Workaround for an NVIDIA bug seen in Super Mario RPG
+     *
+     * We are looking for this pattern:
+     *   %lhs_bfe = BitFieldUExtract %factor_a, #0, #16
+     *   %lhs_mul = IMul32 %lhs_bfe, %factor_b           // potentially optional?
+     *   %lhs_shl = ShiftLeftLogical32 %lhs_mul, #16
+     *   %rhs_bfe = BitFieldUExtract %factor_a, #16, #16
+     *   %result  = IAdd32 %lhs_shl, %rhs_bfe
+     *
+     * And replacing the IAdd32 with a BitwiseOr32
+     *   %result  = BitwiseOr32 %lhs_shl, %rhs_bfe
+     *
+     */
+    IR::Inst* const lhs_shl{inst.Arg(0).TryInstRecursive()};
+    IR::Inst* const rhs_bfe{inst.Arg(1).TryInstRecursive()};
+    if (!lhs_shl || !rhs_bfe) {
+        return;
+    }
+    if (lhs_shl->GetOpcode() != IR::Opcode::ShiftLeftLogical32 ||
+        lhs_shl->Arg(1) != IR::Value{16U}) {
+        return;
+    }
+    if (rhs_bfe->GetOpcode() != IR::Opcode::BitFieldUExtract || rhs_bfe->Arg(1) != IR::Value{16U} ||
+        rhs_bfe->Arg(2) != IR::Value{16U}) {
+        return;
+    }
+    IR::Inst* const lhs_mul{lhs_shl->Arg(0).TryInstRecursive()};
+    if (!lhs_mul) {
+        return;
+    }
+    const bool lhs_mul_optional{lhs_mul->GetOpcode() == IR::Opcode::BitFieldUExtract};
+    if (lhs_mul->GetOpcode() != IR::Opcode::IMul32 &&
+        lhs_mul->GetOpcode() != IR::Opcode::BitFieldUExtract) {
+        return;
+    }
+    IR::Inst* const lhs_bfe{lhs_mul_optional ? lhs_mul : lhs_mul->Arg(0).TryInstRecursive()};
+    if (!lhs_bfe) {
+        return;
+    }
+    if (lhs_bfe->GetOpcode() != IR::Opcode::BitFieldUExtract) {
+        return;
+    }
+    if (lhs_bfe->Arg(1) != IR::Value{0U} || lhs_bfe->Arg(2) != IR::Value{16U}) {
+        return;
+    }
+    IR::IREmitter ir{block, IR::Block::InstructionList::s_iterator_to(inst)};
+    inst.ReplaceUsesWith(ir.BitwiseOr(IR::U32{inst.Arg(0)}, IR::U32{inst.Arg(1)}));
+}
+
+} // Anonymous namespace
+
+void VendorWorkaroundPass(IR::Program& program) {
+    for (IR::Block* const block : program.post_order_blocks) {
+        for (IR::Inst& inst : block->Instructions()) {
+            switch (inst.GetOpcode()) {
+            case IR::Opcode::IAdd32:
+                AddingByteSwapsWorkaround(*block, inst);
+                break;
+            default:
+                break;
+            }
+        }
+    }
+}
+
+} // namespace Shader::Optimization