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

1 files changed, 12 insertions, 9 deletions

diff --git a/gcc/expr.h b/gcc/expr.h
index fea69a2..bd0da5e 100644
--- a/gcc/expr.h
+++ b/gcc/expr.h
@@ -103,12 +103,16 @@ enum block_op_methods
   BLOCK_OP_TAILCALL
 };
 
+typedef rtx (*by_pieces_constfn) (void *, HOST_WIDE_INT, machine_mode);
+
 extern rtx emit_block_move (rtx, rtx, rtx, enum block_op_methods);
 extern rtx emit_block_move_hints (rtx, rtx, rtx, enum block_op_methods,
 			          unsigned int, HOST_WIDE_INT,
 				  unsigned HOST_WIDE_INT,
 				  unsigned HOST_WIDE_INT,
 				  unsigned HOST_WIDE_INT);
+extern rtx emit_block_cmp_hints (rtx, rtx, rtx, tree, rtx, bool,
+				 by_pieces_constfn, void *);
 extern bool emit_storent_insn (rtx to, rtx from);
 
 /* Copy all or part of a value X into registers starting at REGNO.
@@ -173,6 +177,11 @@ extern void use_regs (rtx *, int, int);
 /* Mark a PARALLEL as holding a parameter for the next CALL_INSN.  */
 extern void use_group_regs (rtx *, rtx);
 
+#ifdef GCC_INSN_CODES_H
+extern rtx expand_cmpstrn_or_cmpmem (insn_code, rtx, rtx, rtx, tree, rtx,
+				     HOST_WIDE_INT);
+#endif
+
 /* Write zeros through the storage of OBJECT.
    If OBJECT has BLKmode, SIZE is its length in bytes.  */
 extern rtx clear_storage (rtx, rtx, enum block_op_methods);
@@ -191,10 +200,6 @@ extern bool set_storage_via_setmem (rtx, rtx, rtx, unsigned int,
 				    unsigned HOST_WIDE_INT,
 				    unsigned HOST_WIDE_INT);
 
-extern unsigned HOST_WIDE_INT move_by_pieces_ninsns (unsigned HOST_WIDE_INT,
-						     unsigned int,
-						     unsigned int);
-
 /* Return nonzero if it is desirable to store LEN bytes generated by
    CONSTFUN with several move instructions by store_by_pieces
    function.  CONSTFUNDATA is a pointer which will be passed as argument
@@ -203,8 +208,7 @@ extern unsigned HOST_WIDE_INT move_by_pieces_ninsns (unsigned HOST_WIDE_INT,
    MEMSETP is true if this is a real memset/bzero, not a copy
    of a const string.  */
 extern int can_store_by_pieces (unsigned HOST_WIDE_INT,
-				rtx (*) (void *, HOST_WIDE_INT,
-					 machine_mode),
+				by_pieces_constfn,
 				void *, unsigned int, bool);
 
 /* Generate several move instructions to store LEN bytes generated by
@@ -213,8 +217,7 @@ extern int can_store_by_pieces (unsigned HOST_WIDE_INT,
    ALIGN is maximum alignment we can assume.
    MEMSETP is true if this is a real memset/bzero, not a copy.
    Returns TO + LEN.  */
-extern rtx store_by_pieces (rtx, unsigned HOST_WIDE_INT,
-			    rtx (*) (void *, HOST_WIDE_INT, machine_mode),
+extern rtx store_by_pieces (rtx, unsigned HOST_WIDE_INT, by_pieces_constfn,
 			    void *, unsigned int, bool, int);
 
 /* Emit insns to set X from Y.  */
@@ -295,7 +298,7 @@ rtx get_personality_function (tree);
 /* Determine whether the LEN bytes can be moved by using several move
    instructions.  Return nonzero if a call to move_by_pieces should
    succeed.  */
-extern int can_move_by_pieces (unsigned HOST_WIDE_INT, unsigned int);
+extern bool can_move_by_pieces (unsigned HOST_WIDE_INT, unsigned int);
 
 extern unsigned HOST_WIDE_INT highest_pow2_factor (const_tree);