https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90706
--- Comment #23 from Georg-Johann Lay <gjl at gcc dot gnu.org> --- Created attachment 55130 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=55130&action=edit Test case for -Os -mmcu=attiny40 As it appears, this bug is not fixed completely. For the -mmcu=avrtiny architecture, there is still bloat for even the smallest test cases like: $ avr-gcc bloat.c -mmcu=attiny40 -Os -S char func3 (char c) { return 1 + c; } "GCC: (GNU) 14.0.0 20230520 (experimental)" compiles this to: func3: push r28 ; 22 [c=4 l=1] pushqi1/0 push r29 ; 23 [c=4 l=1] pushqi1/0 push __tmp_reg__ ; 27 [c=4 l=1] *addhi3_sp in r28,__SP_L__ ; 38 [c=4 l=2] *movhi/7 in r29,__SP_H__ /* prologue: function */ /* frame size = 1 */ /* stack size = 3 */ mov r20,r24 ; 18 [c=4 l=1] movqi_insn/0 subi r20,lo8(-(1)) ; 19 [c=4 l=1] *addqi3/1 mov r24,r20 ; 21 [c=4 l=1] movqi_insn/0 /* epilogue start */ pop __tmp_reg__ ; 33 [c=4 l=1] *addhi3_sp pop r29 ; 34 [c=4 l=1] popqi pop r28 ; 35 [c=4 l=1] popqi ret ; 36 [c=0 l=1] return_from_epilogue For reference, avr-gcc v8 generates for this function: func3: /* prologue: function */ /* frame size = 0 */ /* stack size = 0 */ .L__stack_usage = 0 subi r24,lo8(-(1)) ; 6 [c=4 l=1] addqi3/1 /* epilogue start */ ret ; 17 [c=0 l=1] return
