> 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.
GCC32A-1043.patch
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