Procedure local variables and arguments are internaly allocated as global variables. Atalan analyzes procedure call chain and if possible, reuses global variable space to several procedures.

• unused procedure removal
• procedure inlining (procedure, that is called only once is automatically inlined)
• procedure arguments and local variables are implemented using 'global' variables (no stack)
• processor registers are used to pass arguments in & out of procedure
• tail call optimization (call X, return => goto X)

Instruction level optimizations

• multiplication, division and modulus is performed using shift or and when applicable
• when comparing variable that has only two possible value and one of them is 0, always compare to zero
• operation merging (a = a + 10, a = a + 20 => a = a + 30)
• constant variables send to print are converted to strings (a = 30 "[a]" => "30")

Local optimizations

• constant folding
• constant propagation
• common subexpression elimination
• live variable analysis
• optimal operation is chosen according to variable range
• variable merging (X = A, A = 30 => X = 30)

Array optimizations

• 2d array is implemented using index (array of pointers to rows)
• byte array up to 256 bytes is accessed using index register

Control flow optimizations

• goto elimination (eliminate goto to goto)
• dead code elimination
• conditional jump around jump simplification (X if a=b, goto Y, X@, ..., Y@ => Y if a<>b, ..., Y@)

Loop optimizations

• most common variables in loop are replaced by registers (if possible)
• loops counting to byte boundaries ($100, $10000, ...) are implemented using C overflow (and are therefore correct without special tricks!)

Macro expansion

• it is possible to write macros that are expanded in place

Data-flow analysis

• live variable analysis