Re: Making GNU GCC choose_multiplier in expmed.c significantly faster

2018-07-19 Thread colinb2 .
On 7/19/18, Jeff Law wrote: > On 07/10/2018 05:09 AM, colinb2 . wrote: > Improvements to compile time behavior are always worth considering. The points you make below about wide_int might address this, albeit in a somewhat different way from the way I am proposing. > So a key issue wi

Making GNU GCC choose_multiplier in expmed.c significantly faster

2018-07-11 Thread colinb2 .
Clarification: this and my first post assume familiarity with choose_multiplier. lgup=ceiling(log2(divisor)) Currently choose_multiplier initializes mlow, mhigh at post_shift=lgup; initially 2^n<=mlow=mhigh then we need post_shift=lgup and we need to use an extra bit for the multiplier, signified

Making GNU GCC choose_multiplier in expmed.c significantly faster

2018-07-10 Thread colinb2 .
Feel free to copy this email and attachment to anyone who might be interested. I'm very happy to answer any questions anyone has. The program can be compiled and run like this on Linux with GNU GCC: gcc -O2 -o expmed2.exe expmed2.c ./expmed2.exe This email deals with making part of the GNU GCC com