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From: "gjl at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/90706] [10/11/12/13 Regression] Useless code generated for stack / register operations on AVR Date: Sun, 21 May 2023 15:25:57 +0000 [thread overview] Message-ID: <bug-90706-4-IzPtqVjaaw@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-90706-4@http.gcc.gnu.org/bugzilla/> 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
next prev parent reply other threads:[~2023-05-21 15:25 UTC|newest] Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <bug-90706-4@http.gcc.gnu.org/bugzilla/> 2020-03-12 11:59 ` [Bug rtl-optimization/90706] [9/10 " jakub at gcc dot gnu.org 2020-03-13 23:25 ` bseifert at gmx dot at 2020-04-29 16:50 ` gjl at gcc dot gnu.org 2021-06-01 8:14 ` [Bug rtl-optimization/90706] [9/10/11/12 " rguenth at gcc dot gnu.org 2022-05-27 9:40 ` [Bug rtl-optimization/90706] [10/11/12/13 " rguenth at gcc dot gnu.org 2022-06-28 10:37 ` jakub at gcc dot gnu.org 2022-11-01 15:55 ` gjl at gcc dot gnu.org 2022-12-13 14:10 ` vmakarov at gcc dot gnu.org 2022-12-15 19:20 ` cvs-commit at gcc dot gnu.org 2022-12-16 13:59 ` gjl at gcc dot gnu.org 2022-12-16 18:33 ` vmakarov at gcc dot gnu.org 2023-03-02 22:22 ` cvs-commit at gcc dot gnu.org 2023-03-04 13:45 ` gjl at gcc dot gnu.org 2023-03-31 12:42 ` cvs-commit at gcc dot gnu.org 2023-03-31 12:45 ` vmakarov at gcc dot gnu.org 2023-03-31 14:38 ` gjl at gcc dot gnu.org 2023-05-21 15:25 ` gjl at gcc dot gnu.org [this message] 2024-03-05 19:28 ` gjl at gcc dot gnu.org 2024-05-18 8:15 ` gjl at gcc dot gnu.org
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