Re: [PATCH][gdb/testsuite] Fix gdb.ada/float-bits.exp with -m32

[Luis Machado via Gdb-patches <gdb-patches@sourceware.org>]

On 4/14/22 14:14, Tom de Vries via Gdb-patches wrote:
> Hi,
> 
> With test-case gdb.ada/float-bits.exp and native we get:
> ...
> (gdb) print 16llf#7FFFF7FF4054A56FA5B99019A5C8#^M
> $9 = 5.0e+25^M
> (gdb) PASS: gdb.ada/float-bits.exp: print 16llf#7FFFF7FF4054A56FA5B99019A5C8#
> ...
> but with target board unix/-m32 we have instead:
> ...
> (gdb) print 16llf#7FFFF7FF4054A56FA5B99019A5C8#^M
> Cannot export value 2596145952482202326224873165792712 as 96-bits \
>    unsigned integer (must be between 0 and 79228162514264337593543950335)^M
> (gdb) FAIL: gdb.ada/float-bits.exp: print 16llf#7FFFF7FF4054A56FA5B99019A5C8#
> ...
> 
> Fix this by testing whether 16llf is supported by doing ptype long_long_float
> which gets us either:
> ...
> type = <16-byte float>^M
> ...
> or:
> ...
> type = <12-byte float>^M
> ...
> 
> Tested on x86_64-linux with native and unix/-m32.

Unfortunately not all targets support 128-bit long doubles. For arm and 
aarch64 the compiler won't generate a 128-bit float, but a 64-bit float, 
so the 16ll tests won't be meaningful.

FAIL: gdb.ada/float-bits.exp: print val_long_double
FAIL: gdb.ada/float-bits.exp: print val_long_double after assignment

I wonder if it would be best to bail out as soon as we find out the 
target has no support for 128-bit floats. I can write a patch for that.

I'm guessing some 16ll tests still work for 12-byte floats, right?

What do you think?