From 36b85e432865a312aa8edc8978e38266e8a0f14c Mon Sep 17 00:00:00 2001 From: Bernd Schmidt Date: Fri, 3 Jun 2016 14:20:53 +0000 Subject: re PR tree-optimization/52171 (memcmp/strcmp/strncmp can be optimized when the result is tested for [in]equality with 0) PR tree-optimization/52171 * builtins.c (expand_cmpstrn_or_cmpmem): Delete, moved elsewhere. (expand_builtin_memcmp): New arg RESULT_EQ. All callers changed. Look for constant strings. Move some code to emit_block_cmp_hints and use it. * builtins.def (BUILT_IN_MEMCMP_EQ): New. * defaults.h (COMPARE_MAX_PIECES): New macro. * expr.c (move_by_pieces_d, store_by_pieces_d): Remove old structs. (move_by_pieces_1, store_by_pieces_1, store_by_pieces_2): Remvoe. (clear_by_pieces_1): Don't declare. Move definition before use. (can_do_by_pieces): New static function. (can_move_by_pieces): Use it. Return bool. (by_pieces_ninsns): Renamed from move_by_pieces_ninsns. New arg OP. All callers changed. Handle COMPARE_BY_PIECES. (class pieces_addr); New. (pieces_addr::pieces_addr, pieces_addr::decide_autoinc, pieces_addr::adjust, pieces_addr::increment_address, pieces_addr::maybe_predec, pieces_addr::maybe_postinc): New member functions for it. (class op_by_pieces_d): New. (op_by_pieces_d::op_by_pieces_d, op_by_pieces_d::run): New member functions for it. (class move_by_pieces_d, class compare_by_pieces_d, class store_by_pieces_d): New subclasses of op_by_pieces_d. (move_by_pieces_d::prepare_mode, move_by_pieces_d::generate, move_by_pieces_d::finish_endp, store_by_pieces_d::prepare_mode, store_by_pieces_d::generate, store_by_pieces_d::finish_endp, compare_by_pieces_d::generate, compare_by_pieces_d::prepare_mode, compare_by_pieces_d::finish_mode): New member functions. (compare_by_pieces, emit_block_cmp_via_cmpmem): New static functions. (expand_cmpstrn_or_cmpmem): Moved here from builtins.c. (emit_block_cmp_hints): New function. (move_by_pieces, store_by_pieces, clear_by_pieces): Rewrite to just use the newly defined classes. * expr.h (by_pieces_constfn): New typedef. (can_store_by_pieces, store_by_pieces): Use it in arg declarations. (emit_block_cmp_hints, expand_cmpstrn_or_cmpmem): Declare. (move_by_pieces_ninsns): Don't declare. (can_move_by_pieces): Change return value to bool. * target.def (TARGET_USE_BY_PIECES_INFRASTRUCTURE_P): Update docs. (compare_by_pieces_branch_ratio): New hook. * target.h (enum by_pieces_operation): Add COMPARE_BY_PIECES. (by_pieces_ninsns): Declare. * targethooks.c (default_use_by_pieces_infrastructure_p): Handle COMPARE_BY_PIECES. (default_compare_by_pieces_branch_ratio): New function. * targhooks.h (default_compare_by_pieces_branch_ratio): Declare. * doc/tm.texi.in (STORE_MAX_PIECES, COMPARE_MAX_PIECES): Document. * doc/tm.texi: Regenerate. * tree-ssa-strlen.c: Include "builtins.h". (handle_builtin_memcmp): New static function. (strlen_optimize_stmt): Call it for BUILT_IN_MEMCMP. * tree.c (build_common_builtin_nodes): Create __builtin_memcmp_eq. testsuite/ PR tree-optimization/52171 * gcc.dg/pr52171.c: New test. * gcc.target/i386/pr52171.c: New test. From-SVN: r237069 --- gcc/target.def | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) (limited to 'gcc/target.def') diff --git a/gcc/target.def b/gcc/target.def index 5285e57..a4df363 100644 --- a/gcc/target.def +++ b/gcc/target.def @@ -3397,8 +3397,9 @@ Both @var{size} and @var{alignment} are measured in terms of storage\n\ units.\n\ \n\ The parameter @var{op} is one of: @code{CLEAR_BY_PIECES},\n\ -@code{MOVE_BY_PIECES}, @code{SET_BY_PIECES}, @code{STORE_BY_PIECES}.\n\ -These describe the type of memory operation under consideration.\n\ +@code{MOVE_BY_PIECES}, @code{SET_BY_PIECES}, @code{STORE_BY_PIECES} or\n\ +@code{COMPARE_BY_PIECES}. These describe the type of memory operation\n\ +under consideration.\n\ \n\ The parameter @var{speed_p} is true if the code is currently being\n\ optimized for speed rather than size.\n\ @@ -3418,6 +3419,18 @@ move would be greater than that of a library call.", default_use_by_pieces_infrastructure_p) DEFHOOK +(compare_by_pieces_branch_ratio, + "When expanding a block comparison in MODE, gcc can try to reduce the\n\ +number of branches at the expense of more memory operations. This hook\n\ +allows the target to override the default choice. It should return the\n\ +factor by which branches should be reduced over the plain expansion with\n\ +one comparison per @var{mode}-sized piece. A port can also prevent a\n\ +particular mode from being used for block comparisons by returning a\n\ +negative number from this hook.", + int, (machine_mode mode), + default_compare_by_pieces_branch_ratio) + +DEFHOOK (optab_supported_p, "Return true if the optimizers should use optab @var{op} with\n\ modes @var{mode1} and @var{mode2} for optimization type @var{opt_type}.\n\ -- cgit v1.1