[Bug inline-asm/82677] Many projects (linux, coreutils, GMP, gcrypt, openSSL, etc) are misusing asm(divq/divl) etc, potentially resulting in faulty/unintended optimisations

2017-10-23 Thread glisse at gcc dot gnu.org 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82677

--- Comment #3 from Marc Glisse  ---
On x86, by default, the compiler already assumes that flags are clobbered.
That's explained in a comment in GMP's longlong.h at least.

[Bug inline-asm/82677] Many projects (linux, coreutils, GMP, gcrypt, openSSL, etc) are misusing asm(divq/divl) etc, potentially resulting in faulty/unintended optimisations

2017-10-23 Thread infinity0 at pwned dot gg 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82677

--- Comment #2 from infinity0 at pwned dot gg ---
More immutable version of [5]:

[5] https://gmplib.org/repo/gmp/annotate/046bc83644a3/longlong.h#l1574

[Bug inline-asm/82677] Many projects (linux, coreutils, GMP, gcrypt, openSSL, etc) are misusing asm(divq/divl) etc, potentially resulting in faulty/unintended optimisations

2017-10-23 Thread infinity0 at pwned dot gg 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82677

--- Comment #1 from infinity0 at pwned dot gg ---
Created attachment 42440
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42440=edit
Similar test case using macros from GMP et. al.