shader: Fold comparisons and Pack/Unpack16

src/shader_recompiler/ir_opt/constant_propagation_pass.cpp

@@ -3,9 +3,9 @@
 // Refer to the license.txt file included.
 
 #include <algorithm>
+#include <ranges>
 #include <tuple>
 #include <type_traits>
-#include <ranges>
 
 #include "common/bit_cast.h"
 #include "common/bit_util.h"
@@ -332,6 +332,18 @@ void FoldBitCast(IR::Inst& inst, IR::Opcode reverse) {
     }
 }
 
+void FoldInverseFunc(IR::Inst& inst, IR::Opcode reverse) {
+    const IR::Value value{inst.Arg(0)};
+    if (value.IsImmediate()) {
+        return;
+    }
+    IR::Inst* const arg_inst{value.InstRecursive()};
+    if (arg_inst->Opcode() == reverse) {
+        inst.ReplaceUsesWith(arg_inst->Arg(0));
+        return;
+    }
+}
+
 template <typename Func, size_t... I>
 IR::Value EvalImmediates(const IR::Inst& inst, Func&& func, std::index_sequence<I...>) {
     using Traits = LambdaTraits<decltype(func)>;
@@ -372,6 +384,10 @@ void ConstantPropagation(IR::Block& block, IR::Inst& inst) {
         return FoldBitCast<IR::Opcode::BitCastU32F32, u32, f32>(inst, IR::Opcode::BitCastF32U32);
     case IR::Opcode::IAdd64:
         return FoldAdd<u64>(block, inst);
+    case IR::Opcode::PackHalf2x16:
+        return FoldInverseFunc(inst, IR::Opcode::UnpackHalf2x16);
+    case IR::Opcode::UnpackHalf2x16:
+        return FoldInverseFunc(inst, IR::Opcode::PackHalf2x16);
     case IR::Opcode::SelectU1:
     case IR::Opcode::SelectU8:
     case IR::Opcode::SelectU16:
@@ -395,6 +411,30 @@ void ConstantPropagation(IR::Block& block, IR::Inst& inst) {
     case IR::Opcode::ULessThan:
         FoldWhenAllImmediates(inst, [](u32 a, u32 b) { return a < b; });
         return;
+    case IR::Opcode::SLessThanEqual:
+        FoldWhenAllImmediates(inst, [](s32 a, s32 b) { return a <= b; });
+        return;
+    case IR::Opcode::ULessThanEqual:
+        FoldWhenAllImmediates(inst, [](u32 a, u32 b) { return a <= b; });
+        return;
+    case IR::Opcode::SGreaterThan:
+        FoldWhenAllImmediates(inst, [](s32 a, s32 b) { return a > b; });
+        return;
+    case IR::Opcode::UGreaterThan:
+        FoldWhenAllImmediates(inst, [](u32 a, u32 b) { return a > b; });
+        return;
+    case IR::Opcode::SGreaterThanEqual:
+        FoldWhenAllImmediates(inst, [](s32 a, s32 b) { return a >= b; });
+        return;
+    case IR::Opcode::UGreaterThanEqual:
+        FoldWhenAllImmediates(inst, [](u32 a, u32 b) { return a >= b; });
+        return;
+    case IR::Opcode::IEqual:
+        FoldWhenAllImmediates(inst, [](u32 a, u32 b) { return a == b; });
+        return;
+    case IR::Opcode::INotEqual:
+        FoldWhenAllImmediates(inst, [](u32 a, u32 b) { return a != b; });
+        return;
     case IR::Opcode::BitFieldUExtract:
         FoldWhenAllImmediates(inst, [](u32 base, u32 shift, u32 count) {
             if (static_cast<size_t>(shift) + static_cast<size_t>(count) > Common::BitSize<u32>()) {