[Bug tree-optimization/94269] widening_mul should consider block frequency

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94269

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2020-03-23
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Or even simpler like FMA detection which restricts ops to be defined in the
same basic-block:

      /* For now restrict this operations to single basic blocks.  In theory
         we would want to support sinking the multiplication in
         m = a*b;
         if ()
           ma = m + c;
         else
           d = m;
         to form a fma in the then block and sink the multiplication to the
         else block.  */
      if (gimple_bb (use_stmt) != gimple_bb (mul_stmt))
        return false;