[Patch, Fortran] PR fortran/38137: Runtime check for stringlengths to MERGE

[Daniel Kraft]

Tobias Burnus wrote:
> Hi Daniel,
> 
> Daniel Kraft wrote:
>> this patch adds a runtime check (when -fbounds-check is enabled) that
>> the arguments to MERGE have the same string length; currently this is
>> only checked at compile-time when possible.  The patch should be
>> straight forward, if I didn't mess up some of the tree stuff.
>>
>> I'm not sure if other intrinsics are affected as well, but check.c
>> does compile-time checks for same string lengths only for MERGE.  But
>> feel free to suggest others and I can add both compile-time and
>> runtime checks for them :)
> I think MERGE is the only Fortran 2003 intrinsic where the length type
> parameter has to be the same. But the same-length check might be
> recycled for PR 31822, which is about pointer assignment rather than
> actual arguments. (Also there: compile-time check works, run-time check
> is missing.)
> 
> (Currently, I have the problem that I cannot find the "=>" constrain in
> the standard (95/2003) - as all compilers have the compile-time check I
> surely miss something.)

Tobias, thanks for looking at this and the pointer, I will work on PR 
31822 now.

>> Regression test running at the moment on GNU/Linux-x86-32.  Ok for
>> trunk if no regressions?  I believe this is can go in for 4.4 without
>> problems (but can hold on until 4.5 too if you want).
> Looks harmless and is only active with -fbounds-check. Thus: OK for the
> trunk.

Thanks for the quick review, no regressions, thus committed to trunk as 
revision 142791.

Yours,
Daniel

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