Re: [PATCH] simplify-rtx: Simplify sign_extend of lshiftrt to zero_extend (PR68330)

2015-11-16 Thread Eric Botcazou
> Since r230164, in PR68330 combine ends up with a sign_extend of an > lshiftrt by some constant, and it does not know to morph that into a > zero_extract (the extend will always extend with zeroes). I think > it is best to let simplify-rtx always replace such a sign_extend by > a zero_extend, aft

[PATCH] simplify-rtx: Simplify sign_extend of lshiftrt to zero_extend (PR68330)

2015-11-14 Thread Segher Boessenkool
Since r230164, in PR68330 combine ends up with a sign_extend of an lshiftrt by some constant, and it does not know to morph that into a zero_extract (the extend will always extend with zeroes). I think it is best to let simplify-rtx always replace such a sign_extend by a zero_extend, after which e