clang memory usage vs. gcc (and OS X 10.8, 10.9, ...)

[René J.V. Bertin]

On Sunday March 16 2014 14:34:00 Christopher Jones wrote:

> What OSX version are you running ? 3.4 and 3.5 install just fine for me on OSX 10.9… No idea if clang 3.4 or 3.5 are supposed to work on older OSX releases (I know the converse has problems, clang versions older than 3.3 do not install on OSX 10.9).

10.6.8 .


> There will be little point filing a bug report against clang 3.3. The first thing they will ask is if the issue is still there with a newer release. Hence my point above….

As I said, the issue exists with clang 3.4 on Linux too. I've had a chance to time compilation of the same file with gcc 4.8: 18.5 minutes with near 100% CPU. In other words, 3-4 times faster (clang didn't even reach 50%CPU on the same rig).

The file is huge as I said, nearly 13000 lines with heavy use of templates. It's an adapted version of the file at http://gmic.sourceforge.net/ from what I understand. I haven't tried, but that project is small enough to make a good testcase.

> The solution I have used so for is for the file in question, when compiling with clang to disable compiler optimisations, which seem to be the issue. i.e. use -O0 instead of -O2…

I tried -O instead of -O2, didn't help. And not very surprising if indeed it's the use of templates that's the cause of it all...

R.