Re: [PATCH] Fortran: ICE in simplification of array expression involving power [PR107680]

[Harald Anlauf <anlauf@gmx.de>]

Am 16.11.22 um 12:39 schrieb Mikael Morin:
> Le 15/11/2022 à 21:45, Harald Anlauf via Fortran a écrit :
>> Dear all,
>>
>> when constant expressions involve parentheses, array constructors,
>> typespecs, and the power operator (**), we could fail with an ICE
>> during simplification in arith_power.
>>
>> Debugging of the testcase showed we call the proper type conversions
>> needed for the arithmetic operation, but under certain circumstances
>> we seem to lose the typespec on the way to the invocation of the
>> simplification.  We then run into unhandled combinations of operand
>> types.
>>
>> The attached patch is likely a sort of a band-aid to the problem:
>> we check the operand types in arith_power, and if we see that a
>> conversion is (still) needed, we punt and defer the simplification.
>>
>> AFAICT this is safe.  It does not address a possibly deeply
>> covered issue in gfortran, which was suspected when analyzing
>> pr107000.  But as this is elusive, that may be hard to locate
>> and fix.
>>
>> Regtested on x86_64-pc-linux-gnu.  OK for mainline?
>>
> Yes, let's go with this.
> Thanks for investigating.
>

Thanks, pushed.

I've opened a PR for the elusive loss of the typespec so that it
won't be forgotten:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107721

Really a weird thing...