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* [Bug c/100432] New: gcc arm compilation binary output is bigger with -Os than -O2 @ 2021-05-05 12:18 xicojovor at dropjar dot com 2021-05-05 14:27 ` [Bug target/100432] " rearnsha at gcc dot gnu.org ` (2 more replies) 0 siblings, 3 replies; 4+ messages in thread From: xicojovor at dropjar dot com @ 2021-05-05 12:18 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100432 Bug ID: 100432 Summary: gcc arm compilation binary output is bigger with -Os than -O2 Product: gcc Version: 11.1.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c Assignee: unassigned at gcc dot gnu.org Reporter: xicojovor at dropjar dot com Target Milestone: --- example: https://godbolt.org/z/rYxTPdTcd while compiling for ARM, gcc versions after 4 (>= 5) generate a redundant stack frame as can be seen in the attached example, while gcc version 4 generates correct code that is also minimal in size as requested (-Os). The code generation in newer gcc versions is strange even without thinking about the -Os flag, since the generated stack frame is not even used, and the whole 3 instructions (sub sp, str, add sp) are totally not needed (the variable on the stack is not used). also reported in https://bugs.launchpad.net/gcc-arm-embedded/+bug/1927055 (not sure where this should be reported) ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/100432] gcc arm compilation binary output is bigger with -Os than -O2 2021-05-05 12:18 [Bug c/100432] New: gcc arm compilation binary output is bigger with -Os than -O2 xicojovor at dropjar dot com @ 2021-05-05 14:27 ` rearnsha at gcc dot gnu.org 2021-05-06 5:51 ` xicojovor at dropjar dot com 2022-01-05 10:37 ` pinskia at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: rearnsha at gcc dot gnu.org @ 2021-05-05 14:27 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100432 Richard Earnshaw <rearnsha at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |WAITING Ever confirmed|0 |1 Last reconfirmed| |2021-05-05 --- Comment #1 from Richard Earnshaw <rearnsha at gcc dot gnu.org> --- godbolt urls expire in time. Please attach your testcase here. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/100432] gcc arm compilation binary output is bigger with -Os than -O2 2021-05-05 12:18 [Bug c/100432] New: gcc arm compilation binary output is bigger with -Os than -O2 xicojovor at dropjar dot com 2021-05-05 14:27 ` [Bug target/100432] " rearnsha at gcc dot gnu.org @ 2021-05-06 5:51 ` xicojovor at dropjar dot com 2022-01-05 10:37 ` pinskia at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: xicojovor at dropjar dot com @ 2021-05-06 5:51 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100432 --- Comment #2 from xicojovor at dropjar dot com --- The minimal example is: int main(void) { return 0; } void* get_self_address(void) { return (void*)get_self_address; } compiled with -marm -Os -fPIC working good (maybe not the best) with gcc 4.5.4, and not ok with gcc version 5.4, 6.3.0, 10.2, 10.3. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/100432] gcc arm compilation binary output is bigger with -Os than -O2 2021-05-05 12:18 [Bug c/100432] New: gcc arm compilation binary output is bigger with -Os than -O2 xicojovor at dropjar dot com 2021-05-05 14:27 ` [Bug target/100432] " rearnsha at gcc dot gnu.org 2021-05-06 5:51 ` xicojovor at dropjar dot com @ 2022-01-05 10:37 ` pinskia at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu.org @ 2022-01-05 10:37 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100432 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Ever confirmed|1 |0 Status|WAITING |UNCONFIRMED ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-01-05 10:37 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-05-05 12:18 [Bug c/100432] New: gcc arm compilation binary output is bigger with -Os than -O2 xicojovor at dropjar dot com 2021-05-05 14:27 ` [Bug target/100432] " rearnsha at gcc dot gnu.org 2021-05-06 5:51 ` xicojovor at dropjar dot com 2022-01-05 10:37 ` pinskia at gcc dot gnu.org
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