Comments on: What exactly does GCC optimize? http://kometbomb.net/2007/11/07/what-exactly-does-gcc-optimize/ Journal of my adventures in Programming, the Internet and Life. Sun, 28 Feb 2010 22:18:35 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: kometbomb http://kometbomb.net/2007/11/07/what-exactly-does-gcc-optimize/comment-page-1/#comment-106 kometbomb Sun, 11 Nov 2007 15:44:42 +0000 http://kometbomb.net/2007/11/07/what-exactly-does-gcc-optimize/#comment-106 Yes, I know that but I have never seen any of the optimizations that have "unsafe" in front of the flag to break code. However, the motivation between the "-O2 vs. -O3" aspect was that often you see -O2 as the recommended flag (well, it could be because of old documents), while it seems there's no point using that at least on my setup. Your mileage may vary. I'd probably advocate using -O2 in projects that have portable code (you can never know what the Amiga GCC has eaten), though. Also, maybe -O3 leads into worse performance if you have to run the same code on a wide variety of architectures. Yes, I know that but I have never seen any of the optimizations that have “unsafe” in front of the flag to break code. However, the motivation between the “-O2 vs. -O3″ aspect was that often you see -O2 as the recommended flag (well, it could be because of old documents), while it seems there’s no point using that at least on my setup. Your mileage may vary.

I’d probably advocate using -O2 in projects that have portable code (you can never know what the Amiga GCC has eaten), though. Also, maybe -O3 leads into worse performance if you have to run the same code on a wide variety of architectures.

]]> By: Deadfool http://kometbomb.net/2007/11/07/what-exactly-does-gcc-optimize/comment-page-1/#comment-104 Deadfool Sat, 10 Nov 2007 23:05:01 +0000 http://kometbomb.net/2007/11/07/what-exactly-does-gcc-optimize/#comment-104 Have you ever thought that -O2 doesnt have the optimizations that -O3 does? -O2 is supposed to be stable and many time -O3 breaks code. Personally i like -Os Have you ever thought that -O2 doesnt have the optimizations that -O3 does? -O2 is supposed to be stable and many time -O3 breaks code. Personally i like -Os

]]>