From mboxrd@z Thu Jan 1 00:00:00 1970 From: Toon Moene To: egcs@cygnus.com Subject: Re: [EGCS] Re: double alignment patch for x86 Date: Sun, 17 Aug 1997 21:48:08 -0000 Message-id: <9708172035.AA19136@moene.indiv.nluug.nl> In-reply-to: [EGCS] Re: double alignment patch for x86 X-SW-Source: 1997-08/0052.html Marc, > It takes 2 additional cycles per double access.. this > can sum up to 30% runtime penalty on important algorithms > like matrix multiply... This is on a Pentium ? My brother did some experiments on his PPro 180 for me with a code that had almost all DOUBLE PRECISION data in COMMON BLOCKS. Without -malign-double, the code took 18 seconds, with -malign-double 10 seconds, i.e. a factor of almost 2. > It was a actually physicist that actually pointed this > out to me (and H.J.Lu for the libc, I believe). We're both actual physicists :-) Cheers, Toon.