[Bug c++/33293] New: inlining std::inner_product()

["simon dot marshall at misys dot com" <gcc-bugzilla at gcc dot gnu dot org>]

I use std::inner_product() to do the vector multiplication when performing
matrix multiplication.  This involves calling std::inner_product() within 2
nested loops (one across all rows, one across all columns).  Unfortunately,
g++-4.1.2 will not, it seems, inline the call even at -O5.  If I provide my own
version with an inline hint, it improves the speed of my matrix multiplication
by ~15%, which is not to be sniffed at.

I suppose my questions would be:

(a) erm, do you need proof?

(b) should the compiler do the inlining regardless (ie, it's a compiler issue),
or should the declaration of std::inner_product give a hint with the inline
keyword (and perhaps also other functions)?

Simon.


-- 
           Summary: inlining std::inner_product()
           Product: gcc
           Version: 4.2.1
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: simon dot marshall at misys dot com
  GCC host triplet: sparc-sun-solaris2.8


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33293