Re: C compile time

[Steven Bosscher <s dot bosscher at student dot tudelft dot nl>]

Dara Hazeghi wrote:

> Okay, here's the updated table. Checking is disabled
> on all compilers.
>
> gcc version     -O0     -O1     -O2     -O3
> 2.7.2.3         128.04  131.02  163.51  176.01
> 2.8.1           128.86  140.79  182.35  194.63
> 2.90.29         130.60  140.57  186.29  199.32
> 2.91.66         132.44  148.48  203.71  219.21
> 2.95.3          143.38  180.97  250.94  276.85
> 3.0.4           169.79  210.73  320.24  365.15
> 3.2.3           193.48  269.43  424.74  519.85
> 3.3             184.15  282.57  442.64  529.93
> 3.3-branch      184.15  283.89  443.66  535.10
> 3.4-mainline    195.34  302.02  483.84  704.59
> 3.4-mainline*   175.84  269.78  426.77  627.13
> 3.5-tree-ssa    223.33  327.91  503.58  702.11 

So with Andrew P's patch, mainline C is faster than 3.3, hurray!

The slowdown at -O3 is of course due to unit-at-a-time, which can be a 
big memory sucker if there are lots of opportunities to inline static 
functions (there is a PR for that IIRC).  What would that number look 
like with -fno-unit-at-a-time?

Do you also have numbers for binary sizes and runtime performance?  :-)

> *this includes Andrew Pinki's patch for PR10962
That patch looks like a very nice improvement.

Gr.
Steven