cost += 20;
break;
+ case LSHIFT_EXPR:
+ case RSHIFT_EXPR:
+ cost += 20;
+ break;
+
default:
break;
}
free (data);
}
+/* Rewrite a/b to a*(1/b). Return the invariant stmt to process. */
+
+static tree
+rewrite_reciprocal (block_stmt_iterator *bsi)
+{
+ tree stmt, lhs, rhs, stmt1, stmt2, var, name, tmp;
+
+ stmt = bsi_stmt (*bsi);
+ lhs = GENERIC_TREE_OPERAND (stmt, 0);
+ rhs = GENERIC_TREE_OPERAND (stmt, 1);
+
+ /* stmt must be GIMPLE_MODIFY_STMT. */
+ var = create_tmp_var (TREE_TYPE (rhs), "reciptmp");
+ add_referenced_var (var);
+
+ tmp = build2 (RDIV_EXPR, TREE_TYPE (rhs),
+ build_real (TREE_TYPE (rhs), dconst1),
+ TREE_OPERAND (rhs, 1));
+ stmt1 = build_gimple_modify_stmt (var, tmp);
+ name = make_ssa_name (var, stmt1);
+ GIMPLE_STMT_OPERAND (stmt1, 0) = name;
+ tmp = build2 (MULT_EXPR, TREE_TYPE (rhs),
+ name, TREE_OPERAND (rhs, 0));
+ stmt2 = build_gimple_modify_stmt (lhs, tmp);
+
+ /* Replace division stmt with reciprocal and multiply stmts.
+ The multiply stmt is not invariant, so update iterator
+ and avoid rescanning. */
+ bsi_replace (bsi, stmt1, true);
+ bsi_insert_after (bsi, stmt2, BSI_NEW_STMT);
+ SSA_NAME_DEF_STMT (lhs) = stmt2;
+
+ /* Continue processing with invariant reciprocal statement. */
+ return stmt1;
+}
+
+/* Check if the pattern at *BSI is a bittest of the form
+ (A >> B) & 1 != 0 and in this case rewrite it to A & (1 << B) != 0. */
+
+static tree
+rewrite_bittest (block_stmt_iterator *bsi)
+{
+ tree stmt, lhs, rhs, var, name, stmt1, stmt2, t;
+ use_operand_p use;
+
+ stmt = bsi_stmt (*bsi);
+ lhs = GENERIC_TREE_OPERAND (stmt, 0);
+ rhs = GENERIC_TREE_OPERAND (stmt, 1);
+
+ /* Verify that the single use of lhs is a comparison against zero. */
+ if (TREE_CODE (lhs) != SSA_NAME
+ || !single_imm_use (lhs, &use, &stmt1)
+ || TREE_CODE (stmt1) != COND_EXPR)
+ return stmt;
+ t = COND_EXPR_COND (stmt1);
+ if (TREE_OPERAND (t, 0) != lhs
+ || (TREE_CODE (t) != NE_EXPR
+ && TREE_CODE (t) != EQ_EXPR)
+ || !integer_zerop (TREE_OPERAND (t, 1)))
+ return stmt;
+
+ /* Get at the operands of the shift. The rhs is TMP1 & 1. */
+ stmt1 = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 0));
+ if (TREE_CODE (stmt1) != GIMPLE_MODIFY_STMT)
+ return stmt;
+
+ /* There is a conversion inbetween possibly inserted by fold. */
+ t = GIMPLE_STMT_OPERAND (stmt1, 1);
+ if (TREE_CODE (t) == NOP_EXPR
+ || TREE_CODE (t) == CONVERT_EXPR)
+ {
+ t = TREE_OPERAND (t, 0);
+ if (TREE_CODE (t) != SSA_NAME
+ || !has_single_use (t))
+ return stmt;
+ stmt1 = SSA_NAME_DEF_STMT (t);
+ if (TREE_CODE (stmt1) != GIMPLE_MODIFY_STMT)
+ return stmt;
+ t = GIMPLE_STMT_OPERAND (stmt1, 1);
+ }
+
+ /* Verify that B is loop invariant but A is not. Verify that with
+ all the stmt walking we are still in the same loop. */
+ if (TREE_CODE (t) == RSHIFT_EXPR
+ && loop_containing_stmt (stmt1) == loop_containing_stmt (stmt)
+ && outermost_invariant_loop_expr (TREE_OPERAND (t, 1),
+ loop_containing_stmt (stmt1)) != NULL
+ && outermost_invariant_loop_expr (TREE_OPERAND (t, 0),
+ loop_containing_stmt (stmt1)) == NULL)
+ {
+ tree a = TREE_OPERAND (t, 0);
+ tree b = TREE_OPERAND (t, 1);
+
+ /* 1 << B */
+ var = create_tmp_var (TREE_TYPE (a), "shifttmp");
+ add_referenced_var (var);
+ t = fold_build2 (LSHIFT_EXPR, TREE_TYPE (a),
+ build_int_cst (TREE_TYPE (a), 1), b);
+ stmt1 = build_gimple_modify_stmt (var, t);
+ name = make_ssa_name (var, stmt1);
+ GIMPLE_STMT_OPERAND (stmt1, 0) = name;
+
+ /* A & (1 << B) */
+ t = fold_build2 (BIT_AND_EXPR, TREE_TYPE (a), a, name);
+ stmt2 = build_gimple_modify_stmt (lhs, t);
+
+ bsi_insert_before (bsi, stmt1, BSI_SAME_STMT);
+ bsi_replace (bsi, stmt2, true);
+ SSA_NAME_DEF_STMT (lhs) = stmt2;
+
+ return stmt1;
+ }
+
+ return stmt;
+}
+
+
/* Determine the outermost loops in that statements in basic block BB are
invariant, and record them to the LIM_DATA associated with the statements.
Callback for walk_dominator_tree. */
continue;
}
+ rhs = GENERIC_TREE_OPERAND (stmt, 1);
+
/* If divisor is invariant, convert a/b to a*(1/b), allowing reciprocal
to be hoisted out of loop, saving expensive divide. */
if (pos == MOVE_POSSIBLE
- && (rhs = GENERIC_TREE_OPERAND (stmt, 1)) != NULL
&& TREE_CODE (rhs) == RDIV_EXPR
&& flag_unsafe_math_optimizations
&& !flag_trapping_math
loop_containing_stmt (stmt)) != NULL
&& outermost_invariant_loop_expr (rhs,
loop_containing_stmt (stmt)) == NULL)
- {
- tree lhs, stmt1, stmt2, var, name, tmp;
-
- lhs = GENERIC_TREE_OPERAND (stmt, 0);
-
- /* stmt must be GIMPLE_MODIFY_STMT. */
- var = create_tmp_var (TREE_TYPE (rhs), "reciptmp");
- add_referenced_var (var);
-
- tmp = build2 (RDIV_EXPR, TREE_TYPE (rhs),
- build_real (TREE_TYPE (rhs), dconst1),
- TREE_OPERAND (rhs, 1));
- stmt1 = build_gimple_modify_stmt (var, tmp);
- name = make_ssa_name (var, stmt1);
- GIMPLE_STMT_OPERAND (stmt1, 0) = name;
- tmp = build2 (MULT_EXPR, TREE_TYPE (rhs),
- name, TREE_OPERAND (rhs, 0));
- stmt2 = build_gimple_modify_stmt (lhs, tmp);
-
- /* Replace division stmt with reciprocal and multiply stmts.
- The multiply stmt is not invariant, so update iterator
- and avoid rescanning. */
- bsi_replace (&bsi, stmt1, true);
- bsi_insert_after (&bsi, stmt2, BSI_NEW_STMT);
- SSA_NAME_DEF_STMT (lhs) = stmt2;
-
- /* Continue processing with invariant reciprocal statement. */
- stmt = stmt1;
- }
+ stmt = rewrite_reciprocal (&bsi);
+
+ /* If the shift count is invariant, convert (A >> B) & 1 to
+ A & (1 << B) allowing the bit mask to be hoisted out of the loop
+ saving an expensive shift. */
+ if (pos == MOVE_POSSIBLE
+ && TREE_CODE (rhs) == BIT_AND_EXPR
+ && integer_onep (TREE_OPERAND (rhs, 1))
+ && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME
+ && has_single_use (TREE_OPERAND (rhs, 0)))
+ stmt = rewrite_bittest (&bsi);
stmt_ann (stmt)->common.aux = xcalloc (1, sizeof (struct lim_aux_data));
LIM_DATA (stmt)->always_executed_in = outermost;
OSDN Git Service
