[gfortran,patch] Fix constant exponentiation with integer exponent

[Jerry DeLisle]

Jerry DeLisle wrote:
> François-Xavier Coudert wrote:
>>> The patch comes with somewhat long testcases. Regtested on i686-
>>> linux, OK for mainline? Do you think it's OK for 4.2? (I'm not sure,
>>> it's rather invasive... and the cases where the compiler actually got
>>> it wrong were... rather rarely used)
>>
>> After some more thinking (and some testing of the trans-const.c patch
>> for very large integers with -fno-range-check), here's an updated
>> patch. The changes are small, they only make sure that we don't reject
>> i**j when all of the following conditions are fulfilled:
>>  (a) i and j are integers
>>  (b) i is larger than huge(0_4)
>>  (c) i**j overflows (that is, j>0 and i>1)
>>  (d) -fno-range-check is specified.
>> The integer_exponentiation_5.F90 testcase, which uses
>> -fno-range-check, was updated to test this code path.
>>
>> Regtested once more on i686-linux (it needs the patch for PR31262,
>> which can be found here:
>> http://gcc.gnu.org/ml/gcc-patches/2007-03/msg01332.html ; Jerry is
>> currently reviewing it, so it should be commited soon). OK for
>> mainline? Still same question as quoted above for 4.2.
>>
>> Thanks,
>> FX
> 
> I made the mistake of trying this patch without the patch for PR31262 
> and my system went to a very hard never never land when running the test 
> suite.  I am now testing again with the patch for PR31262 in place by 
> itself.  I will then try again with pr30834_4.diff applied secondly.
> 
> Can anyone remember the magic formula to set memory limits on 
> processes.  My system ended up using all 1.5 Gig of memory and then 
> thrashed until I had no choice but the ON - OFF - ON sequence.  Ouch.
> 
> Jerry
> 
Well I tried again and I get massive memory usage and runaway processes.  The 
culprit is f951 when trying to compile integer_exponentiation_3.F90.

The patch went in clean and built fine, but it no worky here.  I must be missing 
something.

X86-64-Gnu/Linux

Jerry