Bitwise const folding (#2071)

Co-authored-by: ike709 <[email protected]>

Author: ike709

DMCompiler/DM/Builders/DMASTFolder.cs

@@ -219,27 +219,6 @@ private DMASTExpression FoldExpression(DMASTExpression? expression) {
 
                 break;
             }
-            case DMASTBinaryAnd binaryAnd: {
-                if (binaryAnd is { LHS: DMASTConstantInteger lhsInt, RHS: DMASTConstantInteger rhsInt }) {
-                    return new DMASTConstantInteger(expression.Location, lhsInt.Value & rhsInt.Value);
-                }
-
-                break;
-            }
-            case DMASTBinaryOr binaryOr: {
-                if (binaryOr is { LHS: DMASTConstantInteger lhsInt, RHS: DMASTConstantInteger rhsInt }) {
-                    return new DMASTConstantInteger(expression.Location, lhsInt.Value | rhsInt.Value);
-                }
-
-                break;
-            }
-            case DMASTBinaryNot binaryNot: {
-                if (binaryNot.Value is DMASTConstantInteger exprInt) {
-                    return new DMASTConstantInteger(expression.Location, (~exprInt.Value) & 0xFFFFFF);
-                }
-
-                break;
-            }
             case DMASTAdd add: {
                 DMASTConstantString? lhsString = add.LHS as DMASTConstantString;
                 DMASTConstantString? rhsString = add.RHS as DMASTConstantString;

DMCompiler/Optimizer/PeepholeOptimizations.cs

@@ -618,6 +618,78 @@ public void Apply(List<IAnnotatedBytecode> input, int index) {
 }
 
 #region Constant Folding
+
+// PushFloat [constant]
+// BitNot
+// -> PushFloat [result]
+internal sealed class ConstFoldBitNot : IPeepholeOptimization {
+    public ReadOnlySpan<DreamProcOpcode> GetOpcodes() {
+        return [
+            DreamProcOpcode.PushFloat,
+            DreamProcOpcode.BitNot
+        ];
+    }
+
+    public void Apply(List<IAnnotatedBytecode> input, int index) {
+        var firstInstruction = IPeepholeOptimization.GetInstructionAndValue(input[index], out var pushVal1);
+
+        var args = new List<IAnnotatedBytecode>(1) {new AnnotatedBytecodeFloat(((~(int)pushVal1) & 0xFFFFFF), firstInstruction.Location)};
+
+        IPeepholeOptimization.ReplaceInstructions(input, index, 2,
+            new AnnotatedBytecodeInstruction(DreamProcOpcode.PushFloat, 1, args));
+    }
+}
+
+// PushFloat [constant]
+// PushFloat [constant]
+// BitOr
+// -> PushFloat [result]
+internal sealed class ConstFoldBitOr : IPeepholeOptimization {
+    public ReadOnlySpan<DreamProcOpcode> GetOpcodes() {
+        return [
+            DreamProcOpcode.PushFloat,
+            DreamProcOpcode.PushFloat,
+            DreamProcOpcode.BitOr,
+        ];
+    }
+
+    public void Apply(List<IAnnotatedBytecode> input, int index) {
+        var firstInstruction = IPeepholeOptimization.GetInstructionAndValue(input[index], out var pushVal1);
+
+        IPeepholeOptimization.GetInstructionAndValue(input[index + 1], out var pushVal2);
+
+        var args = new List<IAnnotatedBytecode>(1) {new AnnotatedBytecodeFloat(((int)pushVal1 | (int)pushVal2), firstInstruction.Location)};
+
+        IPeepholeOptimization.ReplaceInstructions(input, index, 3,
+            new AnnotatedBytecodeInstruction(DreamProcOpcode.PushFloat, 1, args));
+    }
+}
+
+// PushFloat [constant]
+// PushFloat [constant]
+// BitAnd
+// -> PushFloat [result]
+internal sealed class ConstFoldBitAnd : IPeepholeOptimization {
+    public ReadOnlySpan<DreamProcOpcode> GetOpcodes() {
+        return [
+            DreamProcOpcode.PushFloat,
+            DreamProcOpcode.PushFloat,
+            DreamProcOpcode.BitAnd,
+        ];
+    }
+
+    public void Apply(List<IAnnotatedBytecode> input, int index) {
+        var firstInstruction = IPeepholeOptimization.GetInstructionAndValue(input[index], out var pushVal1);
+
+        IPeepholeOptimization.GetInstructionAndValue(input[index + 1], out var pushVal2);
+
+        var args = new List<IAnnotatedBytecode>(1) {new AnnotatedBytecodeFloat(((int)pushVal1 & (int)pushVal2), firstInstruction.Location)};
+
+        IPeepholeOptimization.ReplaceInstructions(input, index, 3,
+            new AnnotatedBytecodeInstruction(DreamProcOpcode.PushFloat, 1, args));
+    }
+}
+
 // PushFloat [constant]
 // PushFloat [constant]
 // Multiply