------- Comment #7 from purnnam1 at naver dot com 2008-03-07 00:05 ------- Although I knew GCC use 80-bit format internally, I thought the result should be same in 80-bit format. Due to the very kind explanation about my problem, I can understand that the result can be changed because the rounding operation occurs two times.
The cause of the problem was 'double rounding'. Ironically, the 80-bit internal format makes MORE BIG ERROR in 64-bit floating point calculation. For 64-bit output, 64-bit internal format will generate the best result becauce IEEE-754 intendeds a result to be nearest to the true value with infinite precision. If GCC adopts 80-bit internal format, the final result in the 64-bit floating point will not be the best because of the unavoidable double rounding operation. So, I think that it's very good decision to support 64-bit internal foramt in GCC 4.x version. If a user uses 64-bit floating point numbers, the user will get the more correct result by this option. Also, I really appreciate that Andrew Pinski lets me know my alais rule violation in C/C++. Due to Andrew's kind advice, I knew how much my violation affects the program performance. It was not just a problem about code portability issue. Thank you again. I reallly appreciate you all. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35488 ------- You are receiving this mail because: ------- You are on the CC list for the bug, or are watching someone who is. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]