[IRA, regresssion] code size regression with IRA

[Hariharan <hariharans at picochip dot com>]

Hi Vlad,
I am attaching a test function which has just a huge switch statement 
with multiple cases doing different things. This function register 
allocates on GCC 4.3.2 with no spills at all (at -Os). The function has 
lots of live ranges that span function calls, but the old allocator 
seemed to handle it quite well. With IRA, i get lots of spills and a 
huge frame usage (160 bytes). Can you have a look and see if this is 
some heuristic going wrong in IRA or just a degenerate case?

I tried this testcase with all the IRA options, but nothing helped much 
in reducing code size/frame size.

Picochip's assembly is RISC and the instructions should be obvious, but 
if you need anything, please refer 
http://www.picochip.com/downloads/picoGcc_reference_manual.pdf or ask 
me! You can ofcourse build picochip target (picochip-unknown-none) on 
mainline if you need to.

Attachments:
ira_regression.tgz - Contains source and assembly from GCC 4.3.2, 4.4.0 
and mainline.

Your help is greatly appreciated. Let me know if you need any more 
information.

Thanks and regards
Hari

Attachment: ira_regression.tgz
Description: application/compressed-tar