CODEWITHSUNDEEP
c++gccclang
jonr
jonr

Reputation: 1163

what flags will improve gcc/clang compile times?

What flags for either gcc or clang will improve compile times? I require debugging to be enabled but any other features are free to be disabled if they will result in faster compiles.

I know there are numerous other ways to improve compile times but I am interested soley in this area.

Upvotes: 6

Views: 7214

Answers (5)

FreeNickname
FreeNickname

Reputation: 7814

As for GCC, you can try multithreaded compilation (-jX flag, where X is a number of cores you have +1, according to Reducing compile times article in the Qt Centre).

UPDATE: It seems that I made a mistake: -jX is a 'make' flag, not GCC. So it will improve linking times if you use make-based build system.

Upvotes: 2

Tomas Andrle
Tomas Andrle

Reputation: 13354

You can also try using precompiled headers.

Upvotes: 3

thecoshman
thecoshman

Reputation: 8650

If we start with our base line as 'compiling with no flags' there are no flags you can set that will increase the compilation time.

Upvotes: -4

NoSenseEtAl
NoSenseEtAl

Reputation: 30128

Try -O1, despite it being counter intuitive afaik it can speed up compilation compared to -O0. Also check out ccache

Upvotes: 3

Greg Hewgill
Greg Hewgill

Reputation: 994301

The largest gain in compile time is found by eliminating the most work done by the compiler - usually optimisation. So, don't enable optimisation (-O) flags.

Upvotes: 7

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