[llvm] r204912 - InstCombine: merge constants in both operands of icmp.

[Tobias Grosser]

On 03/28/2014 03:58 PM, Erik Verbruggen wrote:
> I reverted the patch, together with Reid's follow-up patch.
>
> I'm very interested in suggestions on how to fix this "properly" :-)

Hi Erik,

just to follow up. The regression I have seen was a miscompilation of

telecomm-gsm.execution_time
toast.execution_time

in http://lab.llvm.org:8011/builders/polly-perf-O3/builds/2208.

Later the bots reported that Reid's commit r204948 fixes these miscompiles:

http://lab.llvm.org:8011/builders/polly-perf-O3/builds/2214

For some reason I misinterpreted the buildbots (or did not have the 
results yet) at the point when writing my previous email. So at least 
from a correctness point of view, the fix seemed to have worked for my 
LNT bots and the revert was not necessary to restore correctness. If 
there are no other reasons that motivated the backing out of these 
changes, you could possibly give it another shot.

Cheers,
Tobias