On 10/09/13 14:11, Kyrylo Tkachov wrote: >> On 09/09/13 17:32, Kyrylo Tkachov wrote: >>> Hi all, >>> >>> Shift operations with an immediate can generate a 16-bit encoding when >>> the immediate is 5-bit wide, i.e. in the range [0-31]. Therefore we >>> can use them in IT blocks even with the -mrestrict-it rules. >>> >>> I decided to reuse the "N" constraint with a slight modification by >>> removing the !TARGET_32BIT condition from it. The "N" constraint is >>> only used in a few patterns that are predicated by TARGET_THUMB1 >>> anyway, so there's no reason for the constraint to check for that as well. >>> >> >> Hmm, I see no reason why you can't use the M constraint as ARM does. > > Ok, it seems that the shift_operator predicate takes care of the validation. > It seems we can indeed reuse "M" and I notice it's also used in > thumb2_shiftsi3_short > to generate 16-bit shifts. > > How about this then? > > Tested arm-none-eabi on model with -march=armv8-a. > > Kyrill > > 2013-09-10 Kyrylo Tkachov <kyrylo.tkac...@arm.com> > > * config/arm/arm.md (arm_shiftsi3): New alternative l/l/M. > > 2013-09-10 Kyrylo Tkachov <kyrylo.tkac...@arm.com> > > * gcc.target/arm/thumb-ifcvt-2.c: New test. > >
OK. R.
