On 20/04/15 12:03, Kyrill Tkachov wrote: > > On 18/04/15 15:18, Richard Earnshaw wrote: >> On 15/04/15 16:22, Kyrill Tkachov wrote: >>> Hi all, >>> >>> This patch goes through the arm backend and replaces expressions of the >>> form >>> a >= lo && a <= hi with IN_RANGE (a, lo, hi) which is that tiny bit >>> smaller >>> and easier to read in my opinion. I guess there's also a chance it might >>> make >>> things infinitesimally faster since IN_RANGE evaluates 'a' only once. >>> The patch also substitutes expressions like a > hi || a < lo with >>> !IN_RANGE (a, lo, hi) which, again, conveys the intended meaning more >>> clearly. >>> I tried to make sure not to introduce any off-by-one errors and testing >>> caught some that I had made while writing these. >>> >>> Bootstrapped and tested arm-none-linux-gnueabihf. Built and run SPEC2006 >>> succesfully. >>> >>> Ok for trunk once 5.1 is released? >>> >> I think this is pretty obvious for those cases where the type of the >> range is [unsigned] HOST_WIDE_INT, but much less obvious for those cases >> where the type is just int, or unsigned. Cases that I think need more >> careful examination include vfp3_const_double_index and >> aapcs_vfp_is_call_or_return_candidate, but I haven't gone through every >> instance to check whether there are more cases. > > The definition and comment on IN_RANGE in system.h is: > /* A macro to determine whether a VALUE lies inclusively within a > certain range without evaluating the VALUE more than once. This > macro won't warn if the VALUE is unsigned and the LOWER bound is > zero, as it would e.g. with "VALUE >= 0 && ...". Note the LOWER > bound *is* evaluated twice, and LOWER must not be greater than > UPPER. However the bounds themselves can be either positive or > negative. */ > #define IN_RANGE(VALUE, LOWER, UPPER) \ > ((unsigned HOST_WIDE_INT) (VALUE) - (unsigned HOST_WIDE_INT) (LOWER) \ > <= (unsigned HOST_WIDE_INT) (UPPER) - (unsigned HOST_WIDE_INT) (LOWER)) > > Since it works on positive or negative bounds, I'd think it would work on > signed numbers, wouldn't it? > >> >> I'd be particularly concerned about these if the widening of the result >> caused a code quality regression on a native 32-bit machine (since HWI >> is a 64-bit type). > > That being said, I see a 0.6% size increase on cc1 built on a native > arm-linux > system. This seems like a not trivial increase to me. If that is not > acceptable > then we can drop this patch. >
I suggest we just drop the bits that are not using HWI as the base type. R. > Thanks, > Kyrill > >> >> R. >> >>> Thanks, >>> Kyrill >>> >>> 2015-04-15 Kyrylo Tkachov <kyrylo.tkac...@arm.com> >>> >>> * config/arm/arm.md (*zeroextractsi_compare0_scratch): Use IN_RANGE >>> instead of two compares. >>> (*ne_zeroextractsi): Likewise. >>> (*ite_ne_zeroextractsi): Likewise. >>> (load_multiple): Likewise. >>> (store_multiple): Likewise. >>> * config/arm/arm.h (IS_IWMMXT_REGNUM): Likewise. >>> (IS_IWMMXT_GR_REGNUM): Likewise. >>> (IS_VFP_REGNUM): Likewise. >>> * config/arm/arm.c (arm_return_in_memory): Likewise. >>> (aapcs_vfp_is_call_or_return_candidate): Likewise. >>> (thumb_find_work_register): Likewise. >>> (thumb2_legitimate_address_p): Likewise. >>> (arm_legitimate_index_p): Likewise. >>> (thumb2_legitimate_index_p): Likewise. >>> (thumb1_legitimate_address_p): Likewise. >>> (thumb_legitimize_address): Likewise. >>> (vfp3_const_double_index): Likewise. >>> (neon_immediate_valid_for_logic): Likewise. >>> (bounds_check): Likewise. >>> (load_multiple_sequence): Likewise. >>> (store_multiple_sequence): Likewise. >>> (offset_ok_for_ldrd_strd): Likewise. >>> (callee_saved_reg_p): Likewise. >>> (thumb2_emit_strd_push): Likewise. >>> (arm_output_load_gr): Likewise. >>> (arm_vector_mode_supported_p): Likewise. >>> * config/arm/neon.md (ashldi3_neon_noclobber): Likewise. >>> (ashrdi3_neon_imm_noclobber): Likewise. >>> (lshrdi3_neon_imm_noclobber): Likewise. >>> * config/arm/thumb1.md (*thumb1_addsi3): Likewise. >>> * config/arm/thumb2.md (define_peephole2's after >>> orsi_not_shiftsi_si): >>> Likewise. >
