------- Comment #29 from whaley at cs dot utsa dot edu 2006-07-04 13:15 ------- Guys,
The integer and fp differences do not appear to be strongly related. In particular, on my P4e, gcc 4's integer code is actually faster than gcc 3's. Further, if you look at the assemblies of the integer code, it does not have the extra dependencies that gcc 4's x87 code has. In integer, both gcc 3 and 4 explicitly do all loads to registers. I haven't scoped it in detail, but the main difference appears to be in scheduling, with gcc 3 performing a bunch of loads, then a bunch of computations, and gcc 4 intermixing them more. So, we'd need a new series of runs to see which integer schedule is better, but the integer code should not be studied to solve the x87 problem. Thanks, Clint -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27827
