[fpc-devel] generate assembler with no clear purpose MOV

[Marģers .]

 p.s. tested execution speed and there is no measurable difference.


> asm code
> # [109] bit:= longint(1) shl k;
>     movslq    %ecx,%rdx
>     # Register r8d allocated
>     movl    $1,%r8d
>     # Register edx,edx allocated
>     shlx    %edx,%r8d,%edx
>     # Register r8d released
>     # Register edx allocated
>     movl    %edx,%esi
> # Peephole Optimization: %esi = %edx; changed to minimise pipeline stall (MovXXX2MovXXX)
> # Peephole Optimization: Mov2Nop 4 done


> what purpose serve: movslq    %ecx,%rdx   ?

> movl    %edx,%esi seems unnecessary,
> when just enough would be
> movl    $1,%esi
> shlx    %ecx,%esi,%esi

> _______________________________________________
> fpc-devel maillist - fpc-devel at lists.freepascal.org
https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel