[Bug tree-optimization/57512] Vectorizer: cannot handle accumulation loop of signed char type

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57512

Richard Biener  changed:

   What|Removed |Added

 Resolution|--- |FIXED
 Status|UNCONFIRMED |RESOLVED
  Known to work||10.1.0

--- Comment #3 from Richard Biener  ---
This has been fixed, for GCC 10+ I think.

[Bug tree-optimization/57512] Vectorizer: cannot handle accumulation loop of signed char type

[congh at google dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57512

Cong Hou congh at google dot com changed:

   What|Removed |Added

 CC||congh at google dot com

--- Comment #2 from Cong Hou congh at google dot com ---
Together with the phi function, consider the following gimple code:


loop:
  # sum_phi = phi (sum_signed, sum_init_signed);
  sum_temp = (short unsigned int) sum_phi;
  sum_unsigned = a + sum_temp;
  sum_signed = (short int) sum_unsigned;


Can we transform the above code to the following one?


sum_init_unsigned = (unsigned short int) sum_init_signed;
loop:
  # sum_phi = phi (sum_unsigned, sum_init_unsigned);
  sum_unsigned = a + sum_phi;

sum_signed = (short int) sum_unsigned;


This transformation should let the vectorizer detect the reduction pattern.

[Bug tree-optimization/57512] Vectorizer: cannot handle accumulation loop of signed char type

[bmei at broadcom dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57512

--- Comment #1 from Bingfeng Mei bmei at broadcom dot com ---
Created attachment 30250
  -- http://gcc.gnu.org/bugzilla/attachment.cgi?id=30250action=edit
Vectorized assembly code with unsigned char type