This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: Whats wrong with this pattern?
- To: hubicka at atrey dot karlin dot mff dot cuni dot cz (Jan Hubicka)
- Subject: Re: Whats wrong with this pattern?
- From: Joern Rennecke <amylaar at cygnus dot co dot uk>
- Date: Fri, 23 Jul 1999 14:43:32 +0100 (BST)
- Cc: egcs at egcs dot cygnus dot com
> Is converted into mulhi with subregs.
> I've attempted to avoid this by adding new pattern for subreg case and then
> split it ino mulqi or mulsi. For some purpose this don't work. The patterns
> are still matched with mulhi3 even when it is after my attern.
> Interestingly enought when I disable the pattern code works. Can someone
> please describe me whats wrong?
combine only cares about the instruction count, not about the cost of
the instructions involved.
When it forms a combined pattern, it tries to recognize it. Thus, when
it has generated an HImode mult, it can only match an HImode mult.