[Bug rtl-optimization/78041] Wrong code on ARMv7 with -mthumb -mfpu=neon-fp16 -O0

[wdijkstr at arm dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78041

Wilco <wdijkstr at arm dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |wdijkstr at arm dot com

--- Comment #2 from Wilco <wdijkstr at arm dot com> ---
(In reply to Bernd Edlinger from comment #1)
> some background about this bug can be found here:
> 
> https://gcc.gnu.org/ml/gcc-patches/2016-10/msg01561.html

The <shift>di3_neon pattern does not constrain the input not to overlap with
the output for immediate shifts, and the arm_emit_coreregs_64bit_shift code
does not handle partial overlaps. However it is feasible to fix that by
swapping the order for the various cases.