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* [Bug tree-optimization/94930] New: Failure to optimize out subvsi in expansion of __builtin_memcmp with 1 as the operand with -ftrapv @ 2020-05-03 0:22 gabravier at gmail dot com 2020-05-03 14:45 ` [Bug tree-optimization/94930] " glisse at gcc dot gnu.org ` (2 more replies) 0 siblings, 3 replies; 4+ messages in thread From: gabravier at gmail dot com @ 2020-05-03 0:22 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94930 Bug ID: 94930 Summary: Failure to optimize out subvsi in expansion of __builtin_memcmp with 1 as the operand with -ftrapv Product: gcc Version: 11.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: gabravier at gmail dot com Target Milestone: --- int memcmp1(const void *s, const void *c) { return __builtin_memcmp(s, c, 1); } With -O3 -ftrapv, LLVM outputs this : memcmp1(void const*, void const*): # @memcmp1(void const*, void const*) movzx eax, byte ptr [rdi] movzx ecx, byte ptr [rsi] sub eax, ecx ret GCC outputs this : memcmp1(void const*, void const*): sub rsp, 8 movzx edi, BYTE PTR [rdi] movzx esi, BYTE PTR [rsi] call __subvsi3 add rsp, 8 ret ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/94930] Failure to optimize out subvsi in expansion of __builtin_memcmp with 1 as the operand with -ftrapv 2020-05-03 0:22 [Bug tree-optimization/94930] New: Failure to optimize out subvsi in expansion of __builtin_memcmp with 1 as the operand with -ftrapv gabravier at gmail dot com @ 2020-05-03 14:45 ` glisse at gcc dot gnu.org 2021-04-26 1:18 ` pinskia at gcc dot gnu.org 2021-12-23 5:14 ` pinskia at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: glisse at gcc dot gnu.org @ 2020-05-03 14:45 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94930 --- Comment #1 from Marc Glisse <glisse at gcc dot gnu.org> --- AFAIK -ftrapv doesn't work very well and is kind of abandoned, in favor of -fsanitize=signed-integer-overflow (possibly with -fsanitize-undefined-trap-on-error), which does generate the code you expect. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/94930] Failure to optimize out subvsi in expansion of __builtin_memcmp with 1 as the operand with -ftrapv 2020-05-03 0:22 [Bug tree-optimization/94930] New: Failure to optimize out subvsi in expansion of __builtin_memcmp with 1 as the operand with -ftrapv gabravier at gmail dot com 2020-05-03 14:45 ` [Bug tree-optimization/94930] " glisse at gcc dot gnu.org @ 2021-04-26 1:18 ` pinskia at gcc dot gnu.org 2021-12-23 5:14 ` pinskia at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-04-26 1:18 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94930 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Severity|normal |enhancement ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/94930] Failure to optimize out subvsi in expansion of __builtin_memcmp with 1 as the operand with -ftrapv 2020-05-03 0:22 [Bug tree-optimization/94930] New: Failure to optimize out subvsi in expansion of __builtin_memcmp with 1 as the operand with -ftrapv gabravier at gmail dot com 2020-05-03 14:45 ` [Bug tree-optimization/94930] " glisse at gcc dot gnu.org 2021-04-26 1:18 ` pinskia at gcc dot gnu.org @ 2021-12-23 5:14 ` pinskia at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-12-23 5:14 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94930 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Ever confirmed|0 |1 Last reconfirmed| |2021-12-23 Status|UNCONFIRMED |NEW --- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Confirmed. ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-12-23 5:14 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-05-03 0:22 [Bug tree-optimization/94930] New: Failure to optimize out subvsi in expansion of __builtin_memcmp with 1 as the operand with -ftrapv gabravier at gmail dot com 2020-05-03 14:45 ` [Bug tree-optimization/94930] " glisse at gcc dot gnu.org 2021-04-26 1:18 ` pinskia at gcc dot gnu.org 2021-12-23 5:14 ` pinskia at gcc dot gnu.org
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