2016-10-26 Thomas Preud'homme <thomas.preudhomme@arm.com>
gcc/
* config/arm/arm.c (arm_expand_compare_and_swap): Add new bdst local
variable. Add the new parameter to the insn generator. Set that
parameter to be CC flag for 32-bit targets, bval otherwise. Set the
return value from the negation of that parameter for Thumb-1, keeping
the logic unchanged otherwise except for using bdst as the destination
register of the compare_and_swap insn.
(arm_split_compare_and_swap): Add explanation about how is the value
returned to the function comment. Rename scratch variable to
neg_bval. Adapt initialization of variables holding operands to the
new operand numbers. Use return register to hold result of store
exclusive for Thumb-1, scratch register otherwise. Construct the
appropriate cbranch for Thumb-1 targets, keeping the logic unchanged
for 32-bit targets. Guard Z flag setting to restrict to 32bit targets.
Use gen_cbranchsi4 rather than hand-written conditional branch to loop
for strongly ordered compare_and_swap.
* config/arm/predicates.md (cc_register_operand): New predicate.
* config/arm/sync.md (atomic_compare_and_swap<mode>_1): Use a
match_operand with the new predicate to accept either the CC flag or a
destination register for the boolean return value, restricting it to
CC flag only via constraint. Adapt operand numbers accordingly.
From-SVN: r241577
