From 504279ae0a0ce28ad37f820dcdb7f6557aabef7c Mon Sep 17 00:00:00 2001 From: Richard Sandiford Date: Mon, 9 Sep 2019 17:58:36 +0000 Subject: Simplify the implementation of HARD_REG_SET We have two styles of HARD_REG_SET: a single integer based on HOST_WIDEST_FAST_INT (used when FIRST_PSEUDO_REGISTER is small enough) or an array of integers. One of the nice properties of this arrangement is that: void foo (const HARD_REG_SET); is passed by value as an integer when the set is small enough and by reference otherwise. (This is in constrast to "const HARD_REG_SET &", which would always be passed by reference, and in contrast to passing a structure wrapper like "struct s { T elts[1]; }" by value, where the structure might be passed like a T or by reference, depending on the ABI.) However, one of the disadvantages of using an array is that simple assignment doesn't work. We need to use COPY_HARD_REG_SET instead. This patch uses a structure wrapper around the array, and preserves the above "nice property" using a new const_hard_reg_set typedef. The patch also removes the manual unrolling for small array sizes; I think these days we can rely on the compiler to do that for us. This meant fixing two port-specific quirks: - epiphany passed NULL as a HARD_REG_SET whose value doesn't matter. The patch passes the NO_REGS set instead. - ia64 reused TEST_HARD_REG_BIT and SET_HARD_REG_BIT for arrays that are bigger than HARD_REG_SET. The patch just open-codes them. The patch is probably being too conservative. Very few places actually take advantage of the "nice property" above, and we could have a cleaner interface if we used a structure wrapper for all cases. 2019-09-09 Richard Sandiford gcc/ * hard-reg-set.h (HARD_REG_SET): Define using a typedef rather than a #define. Use a structure rather than an array as the fallback definition. Remove special cases for low array sizes. (const_hard_reg_set): New typedef. (hard_reg_set_subset_p): Use it instead of "const HARD_REG_SET". (hard_reg_set_equal_p, hard_reg_set_intersect_p): Likewise. (hard_reg_set_empty_p): Likewise. (SET_HARD_REG_BIT): Use a function rather than a macro to handle the case in which HARD_REG_SET is a structure. (CLEAR_HARD_REG_BIT, TEST_HARD_REG_BIT, CLEAR_HARD_REG_SET) (SET_HARD_REG_SET, COPY_HARD_REG_SET, COMPL_HARD_REG_SET) (AND_HARD_REG_SET, AND_COMPL_HARD_REG_SET, IOR_HARD_REG_SET) (IOR_COMPL_HARD_REG_SET): Likewise. (hard_reg_set_iterator::pset): Constify the pointer target. (hard_reg_set_iter_init): Take a const_hard_reg_set instead of a "const HARD_REG_SET". Update the handling of non-integer HARD_REG_SETs. * recog.h: Test HARD_CONST instead of CLEAR_HARD_REG_SET. * reload.h: Likewise. * rtl.h (choose_hard_reg_mode): Remove unnecessary line break. * regs.h (in_hard_reg_set_p): Take a const_hard_reg_set instead of a "const HARD_REG_SET". (overlaps_hard_reg_set_p, range_overlaps_hard_reg_set_p): Likewise. (range_in_hard_reg_set_p): Likewise. * ira-costs.c (restrict_cost_classes): Likewise. * shrink-wrap.c (move_insn_for_shrink_wrap): Likewise. * config/epiphany/resolve-sw-modes.c (pass_resolve_sw_modes::execute): Pass a NO_REGS HARD_REG_SET rather than NULL to emit_set_fp_mode. * config/ia64/ia64.c (rws_insn): In the CHECKING_P version, use unsigned HOST_WIDEST_FAST_INT rather than HARD_REG_ELT_TYPE. (rws_insn_set, rws_insn_test): In the CHECKING_P version, take an unsigned int and open-code the HARD_REG_SET operations. From-SVN: r275526 --- gcc/reload.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'gcc/reload.h') diff --git a/gcc/reload.h b/gcc/reload.h index eb49771..86f0fff 100644 --- a/gcc/reload.h +++ b/gcc/reload.h @@ -274,7 +274,7 @@ extern int reload_first_uid; extern int num_not_at_initial_offset; -#if defined SET_HARD_REG_BIT && defined CLEAR_REG_SET +#if defined HARD_CONST && defined CLEAR_REG_SET /* This structure describes instructions which are relevant for reload. Apart from all regular insns, this also includes CODE_LABELs, since they must be examined for register elimination. */ @@ -326,7 +326,7 @@ extern class insn_chain *reload_insn_chain; extern class insn_chain *new_insn_chain (void); #endif -#if defined SET_HARD_REG_BIT +#if defined HARD_CONST extern void compute_use_by_pseudos (HARD_REG_SET *, bitmap); #endif -- cgit v1.1