#include "alloc-pool.h"
#include "basic-block.h"
#include "target.h"
-
+#include "diagnostic.h"
+#include "rtl.h"
+#include "expr.h"
+#include "optabs.h"
/* This structure represents one basic block that either computes a
division, or is a common dominator for basic block that compute a
| TODO_verify_stmts /* todo_flags_finish */
}
};
+
+/* A symbolic number is used to detect byte permutation and selection
+ patterns. Therefore the field N contains an artificial number
+ consisting of byte size markers:
+
+ 0 - byte has the value 0
+ 1..size - byte contains the content of the byte
+ number indexed with that value minus one */
+
+struct symbolic_number {
+ unsigned HOST_WIDEST_INT n;
+ int size;
+};
+
+/* Perform a SHIFT or ROTATE operation by COUNT bits on symbolic
+ number N. Return false if the requested operation is not permitted
+ on a symbolic number. */
+
+static inline bool
+do_shift_rotate (enum tree_code code,
+ struct symbolic_number *n,
+ int count)
+{
+ if (count % 8 != 0)
+ return false;
+
+ /* Zero out the extra bits of N in order to avoid them being shifted
+ into the significant bits. */
+ if (n->size < (int)sizeof (HOST_WIDEST_INT))
+ n->n &= ((unsigned HOST_WIDEST_INT)1 << (n->size * BITS_PER_UNIT)) - 1;
+
+ switch (code)
+ {
+ case LSHIFT_EXPR:
+ n->n <<= count;
+ break;
+ case RSHIFT_EXPR:
+ n->n >>= count;
+ break;
+ case LROTATE_EXPR:
+ n->n = (n->n << count) | (n->n >> ((n->size * BITS_PER_UNIT) - count));
+ break;
+ case RROTATE_EXPR:
+ n->n = (n->n >> count) | (n->n << ((n->size * BITS_PER_UNIT) - count));
+ break;
+ default:
+ return false;
+ }
+ return true;
+}
+
+/* Perform sanity checking for the symbolic number N and the gimple
+ statement STMT. */
+
+static inline bool
+verify_symbolic_number_p (struct symbolic_number *n, gimple stmt)
+{
+ tree lhs_type;
+
+ lhs_type = gimple_expr_type (stmt);
+
+ if (TREE_CODE (lhs_type) != INTEGER_TYPE)
+ return false;
+
+ if (TYPE_PRECISION (lhs_type) != n->size * BITS_PER_UNIT)
+ return false;
+
+ return true;
+}
+
+/* find_bswap_1 invokes itself recursively with N and tries to perform
+ the operation given by the rhs of STMT on the result. If the
+ operation could successfully be executed the function returns the
+ tree expression of the source operand and NULL otherwise. */
+
+static tree
+find_bswap_1 (gimple stmt, struct symbolic_number *n, int limit)
+{
+ enum tree_code code;
+ tree rhs1, rhs2 = NULL;
+ gimple rhs1_stmt, rhs2_stmt;
+ tree source_expr1;
+ enum gimple_rhs_class rhs_class;
+
+ if (!limit || !is_gimple_assign (stmt))
+ return NULL_TREE;
+
+ rhs1 = gimple_assign_rhs1 (stmt);
+
+ if (TREE_CODE (rhs1) != SSA_NAME)
+ return NULL_TREE;
+
+ code = gimple_assign_rhs_code (stmt);
+ rhs_class = gimple_assign_rhs_class (stmt);
+ rhs1_stmt = SSA_NAME_DEF_STMT (rhs1);
+
+ if (rhs_class == GIMPLE_BINARY_RHS)
+ rhs2 = gimple_assign_rhs2 (stmt);
+
+ /* Handle unary rhs and binary rhs with integer constants as second
+ operand. */
+
+ if (rhs_class == GIMPLE_UNARY_RHS
+ || (rhs_class == GIMPLE_BINARY_RHS
+ && TREE_CODE (rhs2) == INTEGER_CST))
+ {
+ if (code != BIT_AND_EXPR
+ && code != LSHIFT_EXPR
+ && code != RSHIFT_EXPR
+ && code != LROTATE_EXPR
+ && code != RROTATE_EXPR
+ && code != NOP_EXPR
+ && code != CONVERT_EXPR)
+ return NULL_TREE;
+
+ source_expr1 = find_bswap_1 (rhs1_stmt, n, limit - 1);
+
+ /* If find_bswap_1 returned NULL STMT is a leaf node and we have
+ to initialize the symbolic number. */
+ if (!source_expr1)
+ {
+ /* Set up the symbolic number N by setting each byte to a
+ value between 1 and the byte size of rhs1. The highest
+ order byte is set to 1 and the lowest order byte to
+ n.size. */
+ n->size = TYPE_PRECISION (TREE_TYPE (rhs1));
+ if (n->size % BITS_PER_UNIT != 0)
+ return NULL_TREE;
+ n->size /= BITS_PER_UNIT;
+ n->n = (sizeof (HOST_WIDEST_INT) < 8 ? 0 :
+ (unsigned HOST_WIDEST_INT)0x01020304 << 32 | 0x05060708);
+ n->n >>= (sizeof (HOST_WIDEST_INT) - n->size) * BITS_PER_UNIT;
+
+ source_expr1 = rhs1;
+ }
+
+ switch (code)
+ {
+ case BIT_AND_EXPR:
+ {
+ int i;
+ unsigned HOST_WIDEST_INT val = widest_int_cst_value (rhs2);
+ unsigned HOST_WIDEST_INT tmp = val;
+
+ /* Only constants masking full bytes are allowed. */
+ for (i = 0; i < n->size; i++, tmp >>= BITS_PER_UNIT)
+ if ((tmp & 0xff) != 0 && (tmp & 0xff) != 0xff)
+ return NULL_TREE;
+
+ n->n &= val;
+ }
+ break;
+ case LSHIFT_EXPR:
+ case RSHIFT_EXPR:
+ case LROTATE_EXPR:
+ case RROTATE_EXPR:
+ if (!do_shift_rotate (code, n, (int)TREE_INT_CST_LOW (rhs2)))
+ return NULL_TREE;
+ break;
+ CASE_CONVERT:
+ {
+ int type_size;
+
+ type_size = TYPE_PRECISION (gimple_expr_type (stmt));
+ if (type_size % BITS_PER_UNIT != 0)
+ return NULL_TREE;
+
+ type_size /= BITS_PER_UNIT;
+
+ if (type_size / BITS_PER_UNIT < (int)(sizeof (HOST_WIDEST_INT)))
+ {
+ /* If STMT casts to a smaller type mask out the bits not
+ belonging to the target type. */
+ n->size = type_size / BITS_PER_UNIT;
+ n->n &= ((unsigned HOST_WIDEST_INT)1 << type_size) - 1;
+ }
+ }
+ break;
+ default:
+ return NULL_TREE;
+ };
+ return verify_symbolic_number_p (n, stmt) ? source_expr1 : NULL;
+ }
+
+ /* Handle binary rhs. */
+
+ if (rhs_class == GIMPLE_BINARY_RHS)
+ {
+ struct symbolic_number n1, n2;
+ tree source_expr2;
+
+ if (code != BIT_IOR_EXPR)
+ return NULL_TREE;
+
+ if (TREE_CODE (rhs2) != SSA_NAME)
+ return NULL_TREE;
+
+ rhs2_stmt = SSA_NAME_DEF_STMT (rhs2);
+
+ switch (code)
+ {
+ case BIT_IOR_EXPR:
+ source_expr1 = find_bswap_1 (rhs1_stmt, &n1, limit - 1);
+
+ if (!source_expr1)
+ return NULL_TREE;
+
+ source_expr2 = find_bswap_1 (rhs2_stmt, &n2, limit - 1);
+
+ if (source_expr1 != source_expr2
+ || n1.size != n2.size)
+ return NULL_TREE;
+
+ n->size = n1.size;
+ n->n = n1.n | n2.n;
+
+ if (!verify_symbolic_number_p (n, stmt))
+ return NULL_TREE;
+
+ break;
+ default:
+ return NULL_TREE;
+ }
+ return source_expr1;
+ }
+ return NULL_TREE;
+}
+
+/* Check if STMT completes a bswap implementation consisting of ORs,
+ SHIFTs and ANDs. Return the source tree expression on which the
+ byte swap is performed and NULL if no bswap was found. */
+
+static tree
+find_bswap (gimple stmt)
+{
+/* The number which the find_bswap result should match in order to
+ have a full byte swap. The insignificant bytes are masked out
+ before using it. */
+ unsigned HOST_WIDEST_INT cmp =
+ sizeof (HOST_WIDEST_INT) < 8 ? 0 :
+ (unsigned HOST_WIDEST_INT)0x08070605 << 32 | 0x04030201;
+
+ struct symbolic_number n;
+ tree source_expr;
+
+ source_expr = find_bswap_1 (stmt, &n,
+ TREE_INT_CST_LOW (
+ TYPE_SIZE_UNIT (gimple_expr_type (stmt))));
+
+ if (!source_expr)
+ return NULL_TREE;
+
+ /* Zero out the extra bits of N and CMP. */
+ if (n.size < (int)sizeof (HOST_WIDEST_INT))
+ {
+ unsigned HOST_WIDEST_INT mask =
+ ((unsigned HOST_WIDEST_INT)1 << (n.size * BITS_PER_UNIT)) - 1;
+
+ n.n &= mask;
+ cmp &= mask;
+ }
+
+ /* A complete byte swap should make the symbolic number to start
+ with the largest digit in the highest order byte. */
+ if (cmp != n.n)
+ return NULL_TREE;
+
+ return source_expr;
+}
+
+/* Find manual byte swap implementations and turn them into a bswap
+ builtin invokation. */
+
+static unsigned int
+execute_optimize_bswap (void)
+{
+ basic_block bb;
+ bool bswap32_p, bswap64_p;
+ bool changed = false;
+
+ if (BITS_PER_UNIT != 8)
+ return 0;
+
+ if (sizeof (HOST_WIDEST_INT) < 8)
+ return 0;
+
+ bswap32_p = (built_in_decls[BUILT_IN_BSWAP32]
+ && optab_handler (bswap_optab, SImode)->insn_code !=
+ CODE_FOR_nothing);
+ bswap64_p = (built_in_decls[BUILT_IN_BSWAP64]
+ && optab_handler (bswap_optab, DImode)->insn_code !=
+ CODE_FOR_nothing);
+
+ if (!bswap32_p && !bswap64_p)
+ return 0;
+
+ FOR_EACH_BB (bb)
+ {
+ gimple_stmt_iterator gsi;
+
+ for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+ {
+ gimple stmt = gsi_stmt (gsi);
+ tree bswap_src;
+ tree fndecl = NULL_TREE;
+ int type_size;
+ gimple call;
+
+ if (!is_gimple_assign (stmt)
+ || gimple_assign_rhs_code (stmt) != BIT_IOR_EXPR)
+ continue;
+
+ type_size = TYPE_PRECISION (gimple_expr_type (stmt));
+
+ switch (type_size)
+ {
+ case 32:
+ if (bswap32_p)
+ fndecl = built_in_decls[BUILT_IN_BSWAP32];
+ break;
+ case 64:
+ if (bswap64_p)
+ fndecl = built_in_decls[BUILT_IN_BSWAP64];
+ break;
+ default:
+ continue;
+ }
+
+ if (!fndecl)
+ continue;
+
+ bswap_src = find_bswap (stmt);
+
+ if (!bswap_src)
+ continue;
+
+ changed = true;
+ call = gimple_build_call (fndecl, 1, bswap_src);
+ gimple_call_set_lhs (call, gimple_assign_lhs (stmt));
+
+ if (dump_file)
+ {
+ fprintf (dump_file, "%d bit bswap implementation found at: ",
+ (int)type_size);
+ print_gimple_stmt (dump_file, stmt, 0, 0);
+ }
+
+ gsi_insert_after (&gsi, call, GSI_SAME_STMT);
+ gsi_remove (&gsi, true);
+ }
+ }
+
+ return (changed ? TODO_dump_func | TODO_update_ssa | TODO_verify_ssa
+ | TODO_verify_stmts : 0);
+}
+
+static bool
+gate_optimize_bswap (void)
+{
+ return flag_expensive_optimizations && optimize;
+}
+
+struct gimple_opt_pass pass_optimize_bswap =
+{
+ {
+ GIMPLE_PASS,
+ "bswap", /* name */
+ gate_optimize_bswap, /* gate */
+ execute_optimize_bswap, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_NONE, /* tv_id */
+ PROP_ssa, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ 0 /* todo_flags_finish */
+ }
+};
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