[PATCH] Better __ashlDI3, __ashrDI3 and __lshrDI3 functions, plus fixed __bswapsi2 function

[Jeff Law]

On 11/10/20 1:14 PM, Jakub Jelinek via Gcc-patches wrote:
> On Tue, Nov 10, 2020 at 08:44:32PM +0100, Stefan Kanthak wrote:
>> Eric Botcazou <botcazou@adacore.com> wrote:
>>
>>>> The implementation of the __ashlDI3(), __ashrDI3() and __lshrDI3() functions
>>>> is rather bad, it yields bad machine code at least on i386 and AMD64. Since
>>>> GCC knows how to shift integers twice the register size these functions can
>>>> be written as one-liners.
>>> These functions are precisely meant to be used when GCC cannot do that.
>> On which processor(s) is GCC unable to generate code for DWtype shifts?
> E.g. avr-none, msp430-elf, pdp11-aout.
> And I see recursive __cmpdi2 calls on avr-none too.

ACK.  I'll pull those [u]cmpdi changes.  They were iffy at best, this
confirms the concerns we both had.

jeff