First naive version of optimizer

internal/commands/add.go

@@ -231,3 +231,6 @@ func (c *AddCommand) Generate(_ *compiler.CompilerContext) ([]string, error) {
 
 	return asm, nil
 }
+
+func (c *AddCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *AddCommand) GetName() string             { return "ADD" }

internal/commands/and.go

@@ -229,3 +229,6 @@ func (c *AndCommand) Generate(_ *compiler.CompilerContext) ([]string, error) {
 
 	return asm, nil
 }
+
+func (c *AndCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *AndCommand) GetName() string             { return "AND" }

internal/commands/break.go

@@ -49,3 +49,6 @@ func (c *BreakCommand) Generate(_ *compiler.CompilerContext) ([]string, error) {
 		fmt.Sprintf("\tjmp %s", c.skipLabel),
 	}, nil
 }
+
+func (c *BreakCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *BreakCommand) GetName() string              { return "BREAK" }

internal/commands/byte.go

@@ -149,3 +149,6 @@ func (c *ByteCommand) Generate(_ *compiler.CompilerContext) ([]string, error) {
 	// Variables are rendered by assembleOutput, not by individual commands
 	return nil, nil
 }
+
+func (c *ByteCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *ByteCommand) GetName() string              { return "BYTE" }

internal/commands/call.go

@@ -75,3 +75,6 @@ func (c *CallCommand) Interpret(line preproc.Line, ctx *compiler.CompilerContext
 func (c *CallCommand) Generate(_ *compiler.CompilerContext) ([]string, error) {
 	return c.asmOutput, nil
 }
+
+func (c *CallCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *CallCommand) GetName() string             { return "CALL" }

internal/commands/case.go

@@ -148,3 +148,6 @@ func (c *CaseCommand) Generate(ctx *compiler.CompilerContext) ([]string, error)
 
 	return asm, nil
 }
+
+func (c *CaseCommand) GetClass() compiler.CmdClass { return compiler.CmdFlowCtrl }
+func (c *CaseCommand) GetName() string              { return "CASE" }

internal/commands/decr.go

@@ -139,3 +139,6 @@ func (c *DecrCommand) Generate(ctx *compiler.CompilerContext) ([]string, error)
 
 	return asm, nil
 }
+
+func (c *DecrCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *DecrCommand) GetName() string             { return "DEC" }

internal/commands/default.go

@@ -76,3 +76,6 @@ func (c *DefaultCommand) Generate(ctx *compiler.CompilerContext) ([]string, erro
 
 	return asm, nil
 }
+
+func (c *DefaultCommand) GetClass() compiler.CmdClass { return compiler.CmdFlowCtrl }
+func (c *DefaultCommand) GetName() string              { return "DEFAULT" }

internal/commands/else.go

@@ -54,3 +54,6 @@ func (c *ElseCommand) Generate(_ *compiler.CompilerContext) ([]string, error) {
 		c.skipLabel,
 	}, nil
 }
+
+func (c *ElseCommand) GetClass() compiler.CmdClass { return compiler.CmdFlowCtrl }
+func (c *ElseCommand) GetName() string              { return "ELSE" }

internal/commands/endif.go

@@ -47,3 +47,6 @@ func (c *EndIfCommand) Interpret(line preproc.Line, ctx *compiler.CompilerContex
 func (c *EndIfCommand) Generate(_ *compiler.CompilerContext) ([]string, error) {
 	return []string{c.endLabel}, nil
 }
+
+func (c *EndIfCommand) GetClass() compiler.CmdClass { return compiler.CmdFlowCtrl }
+func (c *EndIfCommand) GetName() string              { return "ENDIF" }

internal/commands/endswitch.go

@@ -58,3 +58,6 @@ func (c *EndSwitchCommand) Generate(ctx *compiler.CompilerContext) ([]string, er
 
 	return asm, nil
 }
+
+func (c *EndSwitchCommand) GetClass() compiler.CmdClass { return compiler.CmdFlowCtrl }
+func (c *EndSwitchCommand) GetName() string              { return "ENDSWITCH" }

internal/commands/fend.go

@@ -47,3 +47,6 @@ func (c *FendCommand) Generate(ctx *compiler.CompilerContext) ([]string, error)
 	}
 	return lines, nil
 }
+
+func (c *FendCommand) GetClass() compiler.CmdClass { return compiler.CmdBoundary }
+func (c *FendCommand) GetName() string              { return "FEND" }

internal/commands/for.go

@@ -243,3 +243,6 @@ func (c *ForCommand) generateAssignment() []string {
 
 	return asm
 }
+
+func (c *ForCommand) GetClass() compiler.CmdClass { return compiler.CmdFlowCtrl }
+func (c *ForCommand) GetName() string              { return "FOR" }

internal/commands/func.go

@@ -48,3 +48,6 @@ func (c *FuncCommand) Generate(_ *compiler.CompilerContext) ([]string, error) {
 	marker := fmt.Sprintf("; @@FUNC_BEGIN %s", c.funcName)
 	return []string{marker, c.funcName}, nil
 }
+
+func (c *FuncCommand) GetClass() compiler.CmdClass { return compiler.CmdBoundary }
+func (c *FuncCommand) GetName() string              { return "FUNC" }

internal/commands/gosub.go

@@ -222,6 +222,9 @@ func (c *GosubCommand) Generate(ctx *compiler.CompilerContext) ([]string, error)
 	return asm, nil
 }
 
+func (c *GosubCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *GosubCommand) GetName() string             { return "GOSUB" }
+
 func (c *GosubCommand) generatePrePassing() []string {
 	var asm []string
 

internal/commands/goto.go

@@ -98,3 +98,6 @@ func (c *GotoCommand) Generate(_ *compiler.CompilerContext) ([]string, error) {
 	// Jump to computed address
 	return []string{fmt.Sprintf("\tjmp $%04x", c.address)}, nil
 }
+
+func (c *GotoCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *GotoCommand) GetName() string             { return "GOTO" }

internal/commands/if.go

@@ -119,3 +119,6 @@ func (c *IfCommand) Generate(ctx *compiler.CompilerContext) ([]string, error) {
 
 	return cmpAsm, nil
 }
+
+func (c *IfCommand) GetClass() compiler.CmdClass { return compiler.CmdFlowCtrl }
+func (c *IfCommand) GetName() string              { return "IF" }

internal/commands/incr.go

@@ -138,3 +138,6 @@ func (c *IncrCommand) Generate(ctx *compiler.CompilerContext) ([]string, error)
 
 	return asm, nil
 }
+
+func (c *IncrCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *IncrCommand) GetName() string             { return "INC" }

internal/commands/label.go

@@ -46,3 +46,6 @@ func (c *LabelCommand) Interpret(line preproc.Line, _ *compiler.CompilerContext)
 func (c *LabelCommand) Generate(_ *compiler.CompilerContext) ([]string, error) {
 	return []string{c.labelName}, nil
 }
+
+func (c *LabelCommand) GetClass() compiler.CmdClass { return compiler.CmdBoundary }
+func (c *LabelCommand) GetName() string              { return "LABEL" }

internal/commands/let.go

@@ -182,3 +182,6 @@ func (c *LetCommand) Generate(_ *compiler.CompilerContext) ([]string, error) {
 
 	return asm, nil
 }
+
+func (c *LetCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *LetCommand) GetName() string             { return "LET" }

internal/commands/macro.go

@@ -44,3 +44,6 @@ func (c *MacroCommand) Generate(ctx *compiler.CompilerContext) ([]string, error)
 	result = append(result, fmt.Sprintf("; end @%s", c.macroName))
 	return result, nil
 }
+
+func (c *MacroCommand) GetClass() compiler.CmdClass { return compiler.CmdBoundary }
+func (c *MacroCommand) GetName() string              { return "MACRO" }

internal/commands/next.go

@@ -74,6 +74,9 @@ func (c *NextCommand) Generate(ctx *compiler.CompilerContext) ([]string, error)
 	return asm, nil
 }
 
+func (c *NextCommand) GetClass() compiler.CmdClass { return compiler.CmdFlowCtrl }
+func (c *NextCommand) GetName() string              { return "NEXT" }
+
 // generateEndCheck generates code to exit if var == end.
 func (c *NextCommand) generateEndCheck(ctx *compiler.CompilerContext) []string {
 	var asm []string

internal/commands/or.go

@@ -229,3 +229,6 @@ func (c *OrCommand) Generate(_ *compiler.CompilerContext) ([]string, error) {
 
 	return asm, nil
 }
+
+func (c *OrCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *OrCommand) GetName() string             { return "OR" }

internal/commands/origin.go

@@ -54,3 +54,6 @@ func (c *OriginCommand) Interpret(line preproc.Line, ctx *compiler.CompilerConte
 func (c *OriginCommand) Generate(_ *compiler.CompilerContext) ([]string, error) {
 	return []string{fmt.Sprintf("*= $%04x", c.address)}, nil
 }
+
+func (c *OriginCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *OriginCommand) GetName() string              { return "ORIGIN" }

internal/commands/peek.go

@@ -280,6 +280,17 @@ func (c *PeekCommand) Generate(ctx *compiler.CompilerContext) ([]string, error)
 	return asm, nil
 }
 
+func (c *PeekCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *PeekCommand) GetName() string {
+	if c.isZPPointer {
+		return "PEEK:ZP"
+	}
+	if c.isAddrVar {
+		return "PEEK:SM"
+	}
+	return "PEEK"
+}
+
 // parseOffset extracts offset from syntax like "var[offset]"
 // Returns (base, offset) where offset is empty if no brackets found
 func parseOffset(param string) (base string, offset string) {

internal/commands/peekw.go

@@ -281,6 +281,17 @@ func (c *PeekWCommand) Generate(ctx *compiler.CompilerContext) ([]string, error)
 	return asm, nil
 }
 
+func (c *PeekWCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *PeekWCommand) GetName() string {
+	if c.isZPPointer {
+		return "PEEKW:ZP"
+	}
+	if c.isAddrVar {
+		return "PEEKW:SM"
+	}
+	return "PEEKW"
+}
+
 // parseOffsetW extracts offset from syntax like "var[offset]"
 // Returns (base, offset) where offset is empty if no brackets found
 func parseOffsetW(param string) (base string, offset string) {

internal/commands/point.go

@@ -132,3 +132,6 @@ func (c *PointerCommand) Generate(ctx *compiler.CompilerContext) ([]string, erro
 
 	return asm, nil
 }
+
+func (c *PointerCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *PointerCommand) GetName() string             { return "POINT" }

internal/commands/poke.go

@@ -258,6 +258,17 @@ func (c *PokeCommand) Generate(ctx *compiler.CompilerContext) ([]string, error)
 	return asm, nil
 }
 
+func (c *PokeCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *PokeCommand) GetName() string {
+	if c.isZPPointer {
+		return "POKE:ZP"
+	}
+	if c.isAddrVar {
+		return "POKE:SM"
+	}
+	return "POKE"
+}
+
 // parsePOKEOffset extracts offset from syntax like "var[offset]"
 // Returns (base, offset) where offset is empty if no brackets found
 func parsePOKEOffset(param string) (base string, offset string) {

internal/commands/pokew.go

@@ -294,6 +294,17 @@ func (c *PokeWCommand) Generate(ctx *compiler.CompilerContext) ([]string, error)
 	return asm, nil
 }
 
+func (c *PokeWCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *PokeWCommand) GetName() string {
+	if c.isZPPointer {
+		return "POKEW:ZP"
+	}
+	if c.isAddrVar {
+		return "POKEW:SM"
+	}
+	return "POKEW"
+}
+
 // parsePOKEWOffset extracts offset from syntax like "var[offset]"
 // Returns (base, offset) where offset is empty if no brackets found
 func parsePOKEWOffset(param string) (base string, offset string) {

internal/commands/shiftl.go

@@ -510,3 +510,6 @@ func (c *ShiftLCommand) generateWordShiftVar(ctx *compiler.CompilerContext) ([]s
 	return asm, nil
 }
 
+func (c *ShiftLCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *ShiftLCommand) GetName() string              { return "SHL" }
+

internal/commands/shiftr.go

@@ -653,3 +653,5 @@ func (c *ShiftRCommand) generateWordShiftVar(ctx *compiler.CompilerContext) ([]s
 	return asm, nil
 }
 
+func (c *ShiftRCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *ShiftRCommand) GetName() string              { return "SHR" }

internal/commands/subend.go

@@ -42,3 +42,6 @@ func (c *SubEndCommand) Interpret(line preproc.Line, _ *compiler.CompilerContext
 func (c *SubEndCommand) Generate(_ *compiler.CompilerContext) ([]string, error) {
 	return []string{"\trts"}, nil
 }
+
+func (c *SubEndCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *SubEndCommand) GetName() string              { return "SUBEND" }

internal/commands/subtr.go

@@ -251,3 +251,6 @@ func (c *SubtractCommand) Generate(_ *compiler.CompilerContext) ([]string, error
 
 	return asm, nil
 }
+
+func (c *SubtractCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *SubtractCommand) GetName() string              { return "SUB" }

internal/commands/switch.go

@@ -74,3 +74,6 @@ func (c *SwitchCommand) Generate(ctx *compiler.CompilerContext) ([]string, error
 	// The variable will be loaded and compared by each CASE
 	return []string{}, nil
 }
+
+func (c *SwitchCommand) GetClass() compiler.CmdClass { return compiler.CmdFlowCtrl }
+func (c *SwitchCommand) GetName() string              { return "SWITCH" }

internal/commands/wend.go

@@ -57,3 +57,6 @@ func (c *WendCommand) Generate(_ *compiler.CompilerContext) ([]string, error) {
 		c.skipLabel,
 	}, nil
 }
+
+func (c *WendCommand) GetClass() compiler.CmdClass { return compiler.CmdFlowCtrl }
+func (c *WendCommand) GetName() string              { return "WEND" }

internal/commands/while.go

@@ -125,3 +125,6 @@ func (c *WhileCommand) Generate(ctx *compiler.CompilerContext) ([]string, error)
 	asm = append(asm, cmpAsm...)
 	return asm, nil
 }
+
+func (c *WhileCommand) GetClass() compiler.CmdClass { return compiler.CmdFlowCtrl }
+func (c *WhileCommand) GetName() string             { return "WHILE" }

internal/commands/word.go

@@ -204,3 +204,6 @@ func (c *WordCommand) Generate(_ *compiler.CompilerContext) ([]string, error) {
 	// Variables are rendered by assembleOutput, not by individual commands
 	return nil, nil
 }
+
+func (c *WordCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *WordCommand) GetName() string              { return "WORD" }

internal/commands/xor.go

@@ -267,3 +267,6 @@ func (c *XorCommand) Generate(_ *compiler.CompilerContext) ([]string, error) {
 
 	return asm, nil
 }
+
+func (c *XorCommand) GetClass() compiler.CmdClass { return compiler.CmdLinear }
+func (c *XorCommand) GetName() string             { return "XOR" }

internal/compiler/command.go

@@ -7,6 +7,15 @@ import (
 	"c65gm/internal/preproc"
 )
 
+// CmdClass categorizes commands for the peephole optimizer
+type CmdClass int
+
+const (
+	CmdLinear   CmdClass = iota // straight-line code, no visible labels
+	CmdFlowCtrl                 // IF/WHILE/FOR/SWITCH: internal labels, bodies still optimizable
+	CmdBoundary                 // FUNC/FEND/LABEL/MACRO: reset all optimizer state
+)
+
 // Command represents a script command that can interpret source lines and generate assembly
 type Command interface {
 	// WillHandle checks if this command can handle the given line
@@ -20,6 +29,12 @@ type Command interface {
 	// Generate produces assembly output based on previously interpreted line
 	// Returns assembly lines and error if generation fails
 	Generate(ctx *CompilerContext) ([]string, error)
+
+	// GetClass returns the command's optimizer class
+	GetClass() CmdClass
+
+	// GetName returns a short command name for @@OPT annotations (e.g. "LET", "ADD", "POKE")
+	GetName() string
 }
 
 // CommandRegistry manages registered commands and dispatches lines to appropriate handlers

internal/compiler/compiler.go

@@ -6,6 +6,7 @@ import (
 	"path/filepath"
 	"strings"
 
+	"c65gm/internal/optimizer"
 	"c65gm/internal/preproc"
 )
 
@@ -233,6 +234,9 @@ func (c *Compiler) Compile(lines []preproc.Line) ([]string, error) {
 		}
 
 		codeOutput = append(codeOutput, fmt.Sprintf("; %s", line.Text))
+		if len(asmLines) > 0 && c.isOptimizing() {
+			codeOutput = append(codeOutput, fmt.Sprintf("; @@OPT:%s:%s", classString(cmd.GetClass()), cmd.GetName()))
+		}
 		codeOutput = append(codeOutput, asmLines...)
 	}
 
@@ -251,6 +255,11 @@ func (c *Compiler) Compile(lines []preproc.Line) ([]string, error) {
 		return nil, fmt.Errorf("Unclosed SCRIPT MACRO block.")
 	}
 
+	// Peephole optimization pass
+	if cfg := c.getOptimizerConfig(); cfg != nil {
+		codeOutput = optimizer.Optimize(codeOutput, cfg)
+	}
+
 	// Analyze for overlapping absolute addresses in function call chains
 	c.checkAbsoluteOverlaps()
 
@@ -276,6 +285,44 @@ func (c *Compiler) Compile(lines []preproc.Line) ([]string, error) {
 	return c.assembleOutput(codeOutput, removedFuncs), nil
 }
 
+// isOptimizing returns true if any peephole optimization pragma is active
+func (c *Compiler) isOptimizing() bool {
+	if c.ctx == nil || c.ctx.Pragma == nil {
+		return false
+	}
+	idx := c.ctx.Pragma.GetCurrentPragmaSetIndex()
+	ps := c.ctx.Pragma.GetPragmaSetByIndex(idx)
+	cfg := optimizer.NewConfig(ps)
+	return cfg.Any()
+}
+
+// getOptimizerConfig returns optimizer config if optimization is enabled, nil otherwise
+func (c *Compiler) getOptimizerConfig() *optimizer.Config {
+	if c.ctx == nil || c.ctx.Pragma == nil {
+		return nil
+	}
+	idx := c.ctx.Pragma.GetCurrentPragmaSetIndex()
+	ps := c.ctx.Pragma.GetPragmaSetByIndex(idx)
+	cfg := optimizer.NewConfig(ps)
+	if !cfg.Any() {
+		return nil
+	}
+	return cfg
+}
+
+func classString(cls CmdClass) string {
+	switch cls {
+	case CmdLinear:
+		return "LINEAR"
+	case CmdFlowCtrl:
+		return "FLOWCTRL"
+	case CmdBoundary:
+		return "BOUNDARY"
+	default:
+		return "UNKNOWN"
+	}
+}
+
 // printErrorWithContext prints an error with source code context to stderr
 func (c *Compiler) printErrorWithContext(lines []preproc.Line, lineIndex int, err error) {
 	if lineIndex < 0 || lineIndex >= len(lines) {

internal/compiler/compiler_test.go

@@ -49,6 +49,9 @@ func (c *TestBreakCommand) Generate(ctx *CompilerContext) ([]string, error) {
 	}, nil
 }
 
+func (c *TestBreakCommand) GetClass() CmdClass { return CmdLinear }
+func (c *TestBreakCommand) GetName() string     { return "BREAK" }
+
 func TestCompilerArchitecture(t *testing.T) {
 	// Create pragma
 	pragma := preproc.NewPragma()

internal/optimizer/config.go

@@ -0,0 +1,29 @@
+package optimizer
+
+import (
+	"c65gm/internal/preproc"
+)
+
+type Config struct {
+	EnableLoad bool
+	EnableImm  bool
+	EnableJmp  bool
+	EnableSelf bool
+	Debug      bool
+}
+
+func NewConfig(ps preproc.PragmaSet) *Config {
+	all := ps.GetPragma("_P_OPT_ALL") != "" && ps.GetPragma("_P_OPT_ALL") != "0"
+
+	return &Config{
+		EnableLoad: all || (ps.GetPragma("_P_OPT_LOAD") != "" && ps.GetPragma("_P_OPT_LOAD") != "0"),
+		EnableImm:  all || (ps.GetPragma("_P_OPT_IMM") != "" && ps.GetPragma("_P_OPT_IMM") != "0"),
+		EnableJmp:  all || (ps.GetPragma("_P_OPT_JMP") != "" && ps.GetPragma("_P_OPT_JMP") != "0"),
+		EnableSelf: all || (ps.GetPragma("_P_OPT_SELF") != "" && ps.GetPragma("_P_OPT_SELF") != "0"),
+		Debug:      (ps.GetPragma("_P_OPT_DEBUG") != "" && ps.GetPragma("_P_OPT_DEBUG") != "0"),
+	}
+}
+
+func (c *Config) Any() bool {
+	return c.EnableLoad || c.EnableImm || c.EnableJmp || c.EnableSelf
+}

internal/optimizer/debug.go

@@ -0,0 +1,11 @@
+package optimizer
+
+import "fmt"
+
+// debugWithOriginals wraps the current state with a debug comment header
+func debugWithOriginals(lines []asmLine, phase string) []asmLine {
+	header := fmt.Sprintf("; --- %s ---", phase)
+	result := []asmLine{{text: header, isComment: true}}
+	result = append(result, lines...)
+	return result
+}

internal/optimizer/optimizer.go

@@ -0,0 +1,36 @@
+package optimizer
+
+// Optimize applies all enabled peephole passes to the generated ASM lines.
+// Each pass runs sequentially on a parsed representation of the lines.
+// @@OPT markers are stripped from output.
+func Optimize(lines []string, cfg *Config) []string {
+	if cfg == nil || !cfg.Any() {
+		return lines
+	}
+
+	parsed := parseLines(lines)
+
+	if cfg.Debug {
+		parsed = debugWithOriginals(parsed, "before peephole")
+	}
+
+	if cfg.EnableLoad {
+		parsed = passLoadElimination(parsed)
+	}
+	if cfg.EnableImm {
+		parsed = passImmElimination(parsed)
+	}
+	if cfg.EnableJmp {
+		parsed = passJmpNext(parsed)
+	}
+	if cfg.EnableSelf {
+		parsed = passSelfAssignment(parsed)
+	}
+
+	if cfg.Debug {
+		parsed = debugWithOriginals(parsed, "after peephole")
+	}
+
+	parsed = stripOptMarkers(parsed)
+	return linesToString(parsed)
+}

internal/optimizer/optimizer_test.go

@@ -0,0 +1,209 @@
+package optimizer
+
+import (
+	"testing"
+)
+
+func lines(s ...string) []string { return s }
+
+func TestPassLoadElimination(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    []string
+		expected int // expected number of lines after optimization
+	}{
+		{
+			name:     "redundant same variable",
+			input:    lines("\tlda x", "\tsta y", "\tlda x"),
+			expected: 2, // third lda removed
+		},
+		{
+			name:     "not redundant - store to same variable",
+			input:    lines("\tlda x", "\tsta x", "\tlda x"),
+			expected: 3, // X was stored, so A is stale
+		},
+		{
+			name:     "not redundant - arithmetic in between",
+			input:    lines("\tlda x", "\tadc #1", "\tlda x"),
+			expected: 3, // A was modified
+		},
+		{
+			name:     "redundant - label resets state",
+			input:    lines("\tlda x", "label", "\tlda x"),
+			expected: 3, // label resets state, second lda not redundant
+		},
+		{
+			name:     "x register redundant",
+			input:    lines("\tldx counter", "\tldy counter", "\tldx counter"),
+			expected: 2, // third ldx is redundant (X still holds counter)
+		},
+		{
+			name:     "immediate loads not affected",
+			input:    lines("\tlda #5", "\tsta x", "\tlda #5"),
+			expected: 3, // handled by imm pass
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			parsed := parseLines(tt.input)
+			result := passLoadElimination(parsed)
+			cleaned := stripOptMarkers(result)
+			if got := len(cleaned); got != tt.expected {
+				t.Errorf("got %d lines, want %d\ninput: %v\noutput: %v", got, tt.expected, tt.input, linesToString(cleaned))
+			}
+		})
+	}
+}
+
+func TestPassImmElimination(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    []string
+		expected int
+	}{
+		{
+			name:     "redundant same immediate",
+			input:    lines("\tlda #$05", "\tsta y", "\tlda #$05"),
+			expected: 2, // third removed
+		},
+		{
+			name:     "different immediate values",
+			input:    lines("\tlda #5", "\tsta y", "\tlda #3"),
+			expected: 3, // different values
+		},
+		{
+			name:     "arithmetic invalidates",
+			input:    lines("\tlda #5", "\tadc #1", "\tlda #5"),
+			expected: 3, // adc modified A
+		},
+		{
+			name:     "x and y independent",
+			input:    lines("\tldx #$00", "\tldy #$00", "\tldx #$00"),
+			expected: 2, // first ldx removed? No, let me check: ldx #0 then ldy #0, X still 0, so third redundant
+			// Actually: ldx#0(X=0), ldy#0(Y=0,X=0), ldx#0(X=0,redundant)
+			// Result: ldx#0, ldy#0 → 2 lines
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			parsed := parseLines(tt.input)
+			result := passImmElimination(parsed)
+			cleaned := stripOptMarkers(result)
+			if got := len(cleaned); got != tt.expected {
+				t.Errorf("got %d lines, want %d\ninput: %v\noutput: %v", got, tt.expected, tt.input, linesToString(cleaned))
+			}
+		})
+	}
+}
+
+func TestPassJmpNext(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    []string
+		expected int
+	}{
+		{
+			name:     "jmp to next label",
+			input:    lines("\tjmp _L1", "_L1"),
+			expected: 1, // jmp removed
+		},
+		{
+			name:     "jmp not to next label",
+			input:    lines("\tjmp _L1", "\tlda x", "_L1"),
+			expected: 3, // not immediately followed by label
+		},
+		{
+			name:     "label different from jmp target",
+			input:    lines("\tjmp _L1", "_L2"),
+			expected: 2, // different labels
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			parsed := parseLines(tt.input)
+			result := passJmpNext(parsed)
+			cleaned := stripOptMarkers(result)
+			if got := len(cleaned); got != tt.expected {
+				t.Errorf("got %d lines, want %d\ninput: %v\noutput: %v", got, tt.expected, tt.input, linesToString(cleaned))
+			}
+		})
+	}
+}
+
+func TestPassSelfAssignment(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    []string
+		expected int
+	}{
+		{
+			name:     "self assignment",
+			input:    lines("\tlda x", "\tsta x"),
+			expected: 0, // both removed
+		},
+		{
+			name:     "not self - different variables",
+			input:    lines("\tlda x", "\tsta y"),
+			expected: 2, // different
+		},
+		{
+			name:     "not self - immediate load",
+			input:    lines("\tlda #$05", "\tsta #$05"),
+			expected: 2, // immediate + immediate doesn't match
+		},
+		{
+			name:     "not self - SM code pattern (+ offset)",
+			input:    lines("\tlda x", "\tsta _L1+1"),
+			expected: 2, // SM code pattern
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			parsed := parseLines(tt.input)
+			result := passSelfAssignment(parsed)
+			cleaned := stripOptMarkers(result)
+			if got := len(cleaned); got != tt.expected {
+				t.Errorf("got %d lines, want %d\ninput: %v\noutput: %v", got, tt.expected, tt.input, linesToString(cleaned))
+			}
+		})
+	}
+}
+
+func TestPassLoadNoCommentReset(t *testing.T) {
+	// Comments should NOT reset register state
+	parsed := parseLines(lines(
+		"\tlda b",
+		"\tsta a",
+		"; comment",
+		"\tlda b", // should be redundant
+	))
+	result := passLoadElimination(parsed)
+	if len(result) != 3 {
+		t.Errorf("expected 3 lines (comment kept, lda b removed), got %d:\n%v", len(result), linesToString(result))
+	}
+}
+
+func TestOptimizeIntegration(t *testing.T) {
+	input := lines(
+		"; a = b",
+		"; @@OPT:LINEAR:LET",
+		"\tlda b",
+		"\tsta a",
+		"; second use of b (redundant load)",
+		"; @@OPT:LINEAR:LET",
+		"\tlda b",
+		"\tsta c",
+	)
+
+	cfg := &Config{EnableLoad: true}
+	output := Optimize(input, cfg)
+
+	// 2 source comments + 3 asm lines (lda b removed) = 5
+	if len(output) != 5 {
+		t.Errorf("expected 5 lines, got %d:\n%v", len(output), output)
+	}
+}

internal/optimizer/pass_imm.go

@@ -0,0 +1,67 @@
+package optimizer
+
+// passImmElimination removes redundant immediate loads.
+// Pattern: lda #N; ... (no A modification) ...; lda #N → remove second
+// Applies to A, X, Y.
+func passImmElimination(lines []asmLine) []asmLine {
+	rs := newRegState()
+	var result []asmLine
+
+	for _, line := range lines {
+		if !line.isCode {
+			if line.optMarker {
+				continue
+			}
+			if line.isLabel {
+				rs.reset()
+			}
+			result = append(result, line)
+			continue
+		}
+
+		if isChainBreaker(line.opcode) {
+			rs.reset()
+			result = append(result, line)
+			continue
+		}
+
+		if isRedundantImm(line, rs) {
+			continue // remove line
+		}
+
+		updateRegState(line, rs)
+		result = append(result, line)
+	}
+
+	return result
+}
+
+func isRedundantImm(line asmLine, rs *regState) bool {
+	switch line.opcode {
+	case "lda":
+		if isImmediate(line.operand) {
+			val := parseHexOrDec(line.operand[1:])
+			if rs.a.val == val {
+				return true
+			}
+			rs.loadImm("a", val)
+		}
+	case "ldx":
+		if isImmediate(line.operand) {
+			val := parseHexOrDec(line.operand[1:])
+			if rs.x.val == val {
+				return true
+			}
+			rs.loadImm("x", val)
+		}
+	case "ldy":
+		if isImmediate(line.operand) {
+			val := parseHexOrDec(line.operand[1:])
+			if rs.y.val == val {
+				return true
+			}
+			rs.loadImm("y", val)
+		}
+	}
+	return false
+}

internal/optimizer/pass_jmp.go

@@ -0,0 +1,38 @@
+package optimizer
+
+import "strings"
+
+// passJmpNext removes unconditional jumps to the immediately following label.
+// Pattern: jmp L; L: → (remove jmp)
+func passJmpNext(lines []asmLine) []asmLine {
+	var result []asmLine
+	skipNext := false
+
+	for i := 0; i < len(lines); i++ {
+		if skipNext {
+			skipNext = false
+			continue
+		}
+
+		line := lines[i]
+
+		if skipJmpMarker(line) {
+			continue
+		}
+
+		// Check for jmp L followed by label L:
+		if line.isCode && line.opcode == "jmp" && i+1 < len(lines) {
+			next := lines[i+1]
+			if next.isLabel && strings.TrimSpace(next.text) == strings.TrimSpace(line.operand) {
+				// Remove the jmp, keep the label
+				result = append(result, next)
+				skipNext = true
+				continue
+			}
+		}
+
+		result = append(result, line)
+	}
+
+	return result
+}

internal/optimizer/pass_load.go

@@ -0,0 +1,56 @@
+package optimizer
+
+// passLoadElimination removes redundant memory-to-register loads.
+// Pattern: lda X; ... (X not modified) ...; lda X  → remove second
+// Applies to A, X, Y registers identically.
+func passLoadElimination(lines []asmLine) []asmLine {
+	rs := newRegState()
+	var result []asmLine
+
+	for _, line := range lines {
+		if !line.isCode {
+			if line.optMarker {
+				continue
+			}
+			if line.isLabel {
+				rs.reset()
+			}
+			result = append(result, line)
+			continue
+		}
+
+		if isChainBreaker(line.opcode) {
+			rs.reset()
+			result = append(result, line)
+			continue
+		}
+
+		// Check for redundant memory load
+		if line.opcode == "lda" && !isImmediate(line.operand) {
+			if rs.a.src == line.operand {
+				continue // redundant, remove
+			}
+			rs.a.src = line.operand
+		} else if line.opcode == "ldx" && !isImmediate(line.operand) {
+			if rs.x.src == line.operand {
+				continue
+			}
+			rs.x.src = line.operand
+		} else if line.opcode == "ldy" && !isImmediate(line.operand) {
+			if rs.y.src == line.operand {
+				continue
+			}
+			rs.y.src = line.operand
+		} else {
+			updateRegState(line, rs)
+		}
+
+		result = append(result, line)
+	}
+
+	return result
+}
+
+func isImmediate(operand string) bool {
+	return len(operand) > 0 && operand[0] == '#'
+}

internal/optimizer/pass_self.go

@@ -0,0 +1,38 @@
+package optimizer
+
+import "strings"
+
+// passSelfAssignment removes lda X; sta X pairs where the store immediately
+// follows the load and neither line is a branch target.
+func passSelfAssignment(lines []asmLine) []asmLine {
+	var result []asmLine
+	skipNext := false
+
+	for i := 0; i < len(lines); i++ {
+		if skipNext {
+			skipNext = false
+			continue
+		}
+
+		line := lines[i]
+
+		if skipJmpMarker(line) {
+			continue
+		}
+
+		// Check for lda X; sta X
+		if line.isCode && line.opcode == "lda" && !isImmediate(line.operand) && i+1 < len(lines) {
+			next := lines[i+1]
+			if next.isCode && next.opcode == "sta" && next.operand == line.operand {
+				if !strings.Contains(line.operand, "+") {
+					skipNext = true // skip sta on next iteration
+					continue        // skip lda
+				}
+			}
+		}
+
+		result = append(result, line)
+	}
+
+	return result
+}

internal/optimizer/regstate.go

@@ -0,0 +1,140 @@
+package optimizer
+
+import "strings"
+
+type regInfo struct {
+	val int    // -1 = unknown, else the immediate value known to be in reg
+	src string // variable name if loaded from memory (or "" for immediates)
+}
+
+type regState struct {
+	a regInfo
+	x regInfo
+	y regInfo
+}
+
+func newRegState() *regState {
+	return &regState{
+		a: regInfo{val: -1},
+		x: regInfo{val: -1},
+		y: regInfo{val: -1},
+	}
+}
+
+func (rs *regState) reset() {
+	rs.a = regInfo{val: -1}
+	rs.x = regInfo{val: -1}
+	rs.y = regInfo{val: -1}
+}
+
+func (rs *regState) resetA() { rs.a = regInfo{val: -1} }
+func (rs *regState) resetX() { rs.x = regInfo{val: -1} }
+func (rs *regState) resetY() { rs.y = regInfo{val: -1} }
+
+// loadImm records that a register was loaded with an immediate value
+func (rs *regState) loadImm(reg string, val int) {
+	r := regInfo{val: val}
+	switch reg {
+	case "a":
+		rs.a = r
+	case "x":
+		rs.x = r
+	case "y":
+		rs.y = r
+	}
+}
+
+// loadMem records that a register was loaded from a memory location
+func (rs *regState) loadMem(reg, varName string) {
+	r := regInfo{val: -1, src: varName}
+	switch reg {
+	case "a":
+		rs.a = r
+	case "x":
+		rs.x = r
+	case "y":
+		rs.y = r
+	}
+}
+
+// storeInvalidate marks that a memory location was written.
+// If any register's src matches, that register becomes "unknown" (value gone).
+func (rs *regState) storeInvalidate(varName string) {
+	if rs.a.src == varName {
+		rs.a.src = ""
+		rs.a.val = -1
+	}
+	if rs.x.src == varName {
+		rs.x.src = ""
+		rs.x.val = -1
+	}
+	if rs.y.src == varName {
+		rs.y.src = ""
+		rs.y.val = -1
+	}
+}
+
+// isChainBreaker returns true for instructions that reset all register tracking
+func isChainBreaker(opcode string) bool {
+	switch opcode {
+	case "jmp", "jsr", "rts", "rti", "brk":
+		return true
+	}
+	return false
+}
+
+// updateRegState updates the register state machine for a code line
+func updateRegState(line asmLine, rs *regState) {
+	if !line.isCode {
+		return
+	}
+
+	switch line.opcode {
+	case "lda":
+		if strings.HasPrefix(line.operand, "#") {
+			rs.loadImm("a", parseHexOrDec(line.operand[1:]))
+		} else {
+			rs.loadMem("a", line.operand)
+		}
+	case "ldx":
+		if strings.HasPrefix(line.operand, "#") {
+			rs.loadImm("x", parseHexOrDec(line.operand[1:]))
+		} else {
+			rs.loadMem("x", line.operand)
+		}
+	case "ldy":
+		if strings.HasPrefix(line.operand, "#") {
+			rs.loadImm("y", parseHexOrDec(line.operand[1:]))
+		} else {
+			rs.loadMem("y", line.operand)
+		}
+	case "sta":
+		rs.storeInvalidate(line.operand)
+	case "stx":
+		rs.storeInvalidate(line.operand)
+	case "sty":
+		rs.storeInvalidate(line.operand)
+	case "inc", "dec":
+		rs.storeInvalidate(line.operand)
+	case "tax":
+		rs.x = regInfo{val: -1, src: rs.a.src}
+	case "tay":
+		rs.y = regInfo{val: -1, src: rs.a.src}
+	case "txa":
+		rs.a = regInfo{val: -1, src: rs.x.src}
+	case "tya":
+		rs.a = regInfo{val: -1, src: rs.y.src}
+	case "inx", "dex":
+		rs.resetX()
+	case "iny", "dey":
+		rs.resetY()
+	case "asl", "lsr", "rol", "ror", "adc", "sbc", "and", "ora", "eor", "pla":
+		rs.resetA()
+	case "plp":
+		rs.reset()
+	case "tsx":
+		rs.resetX()
+	case "txs":
+		// SP doesn't affect register tracking
+	}
+}

internal/optimizer/scanner.go

@@ -0,0 +1,97 @@
+package optimizer
+
+import (
+	"strconv"
+	"strings"
+)
+
+// parseHexOrDec parses an ACME-style number: $ff or 255
+func parseHexOrDec(s string) int {
+	if strings.HasPrefix(s, "$") {
+		v, _ := strconv.ParseInt(s[1:], 16, 16)
+		return int(v)
+	}
+	// Strip trailing characters after the number (e.g., ",y" in "5,y")
+	if idx := strings.IndexAny(s, ",)"); idx >= 0 {
+		s = s[:idx]
+	}
+	v, _ := strconv.ParseInt(s, 10, 16)
+	return int(v)
+}
+
+type asmLine struct {
+	text      string
+	isLabel   bool
+	isCode    bool
+	isComment bool
+	optMarker bool
+	opcode    string
+	operand   string
+}
+
+func parseLines(lines []string) []asmLine {
+	var result []asmLine
+	for _, l := range lines {
+		al := asmLine{text: l}
+
+		if l == "" {
+			result = append(result, al)
+			continue
+		}
+
+		if strings.HasPrefix(l, "; @@OPT:") {
+			al.optMarker = true
+			al.isComment = true
+			result = append(result, al)
+			continue
+		}
+
+		if strings.HasPrefix(l, ";") {
+			al.isComment = true
+			result = append(result, al)
+			continue
+		}
+
+		if l[0] == '\t' {
+			al.isCode = true
+			parts := strings.Fields(l)
+			if len(parts) > 0 {
+				al.opcode = strings.ToLower(parts[0])
+			}
+			if len(parts) > 1 {
+				al.operand = parts[1]
+			}
+		} else {
+			al.isLabel = true
+		}
+
+		result = append(result, al)
+	}
+	return result
+}
+
+// stripOptMarkers removes @@OPT comment lines from the output
+func stripOptMarkers(lines []asmLine) []asmLine {
+	var result []asmLine
+	for _, l := range lines {
+		if l.optMarker {
+			continue
+		}
+		result = append(result, l)
+	}
+	return result
+}
+
+func linesToString(lines []asmLine) []string {
+	var result []string
+	for _, l := range lines {
+		result = append(result, l.text)
+	}
+	return result
+}
+
+// skipJmpMarker returns true if the line is an @@OPT comment (to be skipped in pass logic)
+func skipJmpMarker(line asmLine) bool {
+	return line.optMarker
+}
+