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Re: g++ Long compile times
- From: Andrew Haley <aph at redhat dot com>
- To: gcc-help at gcc dot gnu dot org
- Date: Mon, 16 Aug 2010 12:38:35 +0100
- Subject: Re: g++ Long compile times
- References: <4C66D953.6080101@seanet.com>
On 08/14/2010 06:58 PM, Brad Bell wrote:
> The program below is not very smart and repeats a pattern over and over
> (it is a simplification of a program that is automatically generated by
> a modeling language). It seems that the compiler is also not very smart
> and is repeating some calculations over and over.
>
> When I use g++ to compile the program with
> EXTRA_CLASS_OBJECTS=0
> the compile time is about 3 seconds. When
> EXTRA_CLASS_OBJECTS=1
> the compile time is about 12 seconds.
> (See the end of this message for the output of gcc -v on my system.)
>
> The attached file gcc_slow.sh is a bash script that can be used to test
> this
> on any system. If you execute
> ./gcc_slow.sh
> you will get a help message that describes how it works.
>
> Are there compile time options for gcc that can significantly reduce the
> g++
> compile for EXTRA_CLASS_OBJECTS=1 case in the example program below ?
I don't think so. You're asking the C++ front-end to do a lot more work,
so it takes a lot more time.
Andrew.