-/* Switch Conversion converts variable initializations based on switch
- statements to initializations from a static array.
- Copyright (C) 2006, 2008 Free Software Foundation, Inc.
- Contributed by Martin Jambor <jamborm@suse.cz>
+/* Lower GIMPLE_SWITCH expressions to something more efficient than
+ a jump table.
+ Copyright (C) 2006-2015 Free Software Foundation, Inc.
This file is part of GCC.
Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301, USA. */
+/* This file handles the lowering of GIMPLE_SWITCH to an indexed
+ load, or a series of bit-test-and-branch expressions. */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "params.h"
+#include "flags.h"
+#include "alias.h"
+#include "symtab.h"
+#include "tree.h"
+#include "fold-const.h"
+#include "varasm.h"
+#include "stor-layout.h"
+#include "predict.h"
+#include "hard-reg-set.h"
+#include "function.h"
+#include "dominance.h"
+#include "cfg.h"
+#include "cfganal.h"
+#include "basic-block.h"
+#include "tree-ssa-alias.h"
+#include "internal-fn.h"
+#include "gimple-expr.h"
+#include "gimple.h"
+#include "gimplify.h"
+#include "gimple-iterator.h"
+#include "gimplify-me.h"
+#include "gimple-ssa.h"
+#include "cgraph.h"
+#include "tree-cfg.h"
+#include "tree-phinodes.h"
+#include "stringpool.h"
+#include "tree-ssanames.h"
+#include "tree-pass.h"
+#include "gimple-pretty-print.h"
+#include "cfgloop.h"
+
+/* ??? For lang_hooks.types.type_for_mode, but is there a word_mode
+ type in the GIMPLE type system that is language-independent? */
+#include "langhooks.h"
+
+/* Need to include expr.h and optabs.h for lshift_cheap_p. */
+#include "rtl.h"
+#include "insn-config.h"
+#include "expmed.h"
+#include "dojump.h"
+#include "explow.h"
+#include "calls.h"
+#include "emit-rtl.h"
+#include "stmt.h"
+#include "expr.h"
+#include "insn-codes.h"
+#include "optabs.h"
+\f
+/* Maximum number of case bit tests.
+ FIXME: This should be derived from PARAM_CASE_VALUES_THRESHOLD and
+ targetm.case_values_threshold(), or be its own param. */
+#define MAX_CASE_BIT_TESTS 3
+
+/* Split the basic block at the statement pointed to by GSIP, and insert
+ a branch to the target basic block of E_TRUE conditional on tree
+ expression COND.
+
+ It is assumed that there is already an edge from the to-be-split
+ basic block to E_TRUE->dest block. This edge is removed, and the
+ profile information on the edge is re-used for the new conditional
+ jump.
+
+ The CFG is updated. The dominator tree will not be valid after
+ this transformation, but the immediate dominators are updated if
+ UPDATE_DOMINATORS is true.
+
+ Returns the newly created basic block. */
+
+static basic_block
+hoist_edge_and_branch_if_true (gimple_stmt_iterator *gsip,
+ tree cond, edge e_true,
+ bool update_dominators)
+{
+ tree tmp;
+ gcond *cond_stmt;
+ edge e_false;
+ basic_block new_bb, split_bb = gsi_bb (*gsip);
+ bool dominated_e_true = false;
+
+ gcc_assert (e_true->src == split_bb);
+
+ if (update_dominators
+ && get_immediate_dominator (CDI_DOMINATORS, e_true->dest) == split_bb)
+ dominated_e_true = true;
+
+ tmp = force_gimple_operand_gsi (gsip, cond, /*simple=*/true, NULL,
+ /*before=*/true, GSI_SAME_STMT);
+ cond_stmt = gimple_build_cond_from_tree (tmp, NULL_TREE, NULL_TREE);
+ gsi_insert_before (gsip, cond_stmt, GSI_SAME_STMT);
+
+ e_false = split_block (split_bb, cond_stmt);
+ new_bb = e_false->dest;
+ redirect_edge_pred (e_true, split_bb);
+
+ e_true->flags &= ~EDGE_FALLTHRU;
+ e_true->flags |= EDGE_TRUE_VALUE;
+
+ e_false->flags &= ~EDGE_FALLTHRU;
+ e_false->flags |= EDGE_FALSE_VALUE;
+ e_false->probability = REG_BR_PROB_BASE - e_true->probability;
+ e_false->count = split_bb->count - e_true->count;
+ new_bb->count = e_false->count;
+
+ if (update_dominators)
+ {
+ if (dominated_e_true)
+ set_immediate_dominator (CDI_DOMINATORS, e_true->dest, split_bb);
+ set_immediate_dominator (CDI_DOMINATORS, e_false->dest, split_bb);
+ }
+
+ return new_bb;
+}
+
+
+/* Return true if a switch should be expanded as a bit test.
+ RANGE is the difference between highest and lowest case.
+ UNIQ is number of unique case node targets, not counting the default case.
+ COUNT is the number of comparisons needed, not counting the default case. */
+
+static bool
+expand_switch_using_bit_tests_p (tree range,
+ unsigned int uniq,
+ unsigned int count, bool speed_p)
+{
+ return (((uniq == 1 && count >= 3)
+ || (uniq == 2 && count >= 5)
+ || (uniq == 3 && count >= 6))
+ && lshift_cheap_p (speed_p)
+ && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0
+ && compare_tree_int (range, 0) > 0);
+}
+\f
+/* Implement switch statements with bit tests
+
+A GIMPLE switch statement can be expanded to a short sequence of bit-wise
+comparisons. "switch(x)" is converted into "if ((1 << (x-MINVAL)) & CST)"
+where CST and MINVAL are integer constants. This is better than a series
+of compare-and-banch insns in some cases, e.g. we can implement:
+
+ if ((x==4) || (x==6) || (x==9) || (x==11))
+
+as a single bit test:
+
+ if ((1<<x) & ((1<<4)|(1<<6)|(1<<9)|(1<<11)))
+
+This transformation is only applied if the number of case targets is small,
+if CST constains at least 3 bits, and "1 << x" is cheap. The bit tests are
+performed in "word_mode".
+
+The following example shows the code the transformation generates:
+
+ int bar(int x)
+ {
+ switch (x)
+ {
+ case '0': case '1': case '2': case '3': case '4':
+ case '5': case '6': case '7': case '8': case '9':
+ case 'A': case 'B': case 'C': case 'D': case 'E':
+ case 'F':
+ return 1;
+ }
+ return 0;
+ }
+
+==>
+
+ bar (int x)
+ {
+ tmp1 = x - 48;
+ if (tmp1 > (70 - 48)) goto L2;
+ tmp2 = 1 << tmp1;
+ tmp3 = 0b11111100000001111111111;
+ if ((tmp2 & tmp3) != 0) goto L1 ; else goto L2;
+ L1:
+ return 1;
+ L2:
+ return 0;
+ }
+
+TODO: There are still some improvements to this transformation that could
+be implemented:
+
+* A narrower mode than word_mode could be used if that is cheaper, e.g.
+ for x86_64 where a narrower-mode shift may result in smaller code.
+
+* The compounded constant could be shifted rather than the one. The
+ test would be either on the sign bit or on the least significant bit,
+ depending on the direction of the shift. On some machines, the test
+ for the branch would be free if the bit to test is already set by the
+ shift operation.
+
+This transformation was contributed by Roger Sayle, see this e-mail:
+ http://gcc.gnu.org/ml/gcc-patches/2003-01/msg01950.html
+*/
+
+/* A case_bit_test represents a set of case nodes that may be
+ selected from using a bit-wise comparison. HI and LO hold
+ the integer to be tested against, TARGET_EDGE contains the
+ edge to the basic block to jump to upon success and BITS
+ counts the number of case nodes handled by this test,
+ typically the number of bits set in HI:LO. The LABEL field
+ is used to quickly identify all cases in this set without
+ looking at label_to_block for every case label. */
+
+struct case_bit_test
+{
+ wide_int mask;
+ edge target_edge;
+ tree label;
+ int bits;
+};
+
+/* Comparison function for qsort to order bit tests by decreasing
+ probability of execution. Our best guess comes from a measured
+ profile. If the profile counts are equal, break even on the
+ number of case nodes, i.e. the node with the most cases gets
+ tested first.
+
+ TODO: Actually this currently runs before a profile is available.
+ Therefore the case-as-bit-tests transformation should be done
+ later in the pass pipeline, or something along the lines of
+ "Efficient and effective branch reordering using profile data"
+ (Yang et. al., 2002) should be implemented (although, how good
+ is a paper is called "Efficient and effective ..." when the
+ latter is implied by the former, but oh well...). */
+
+static int
+case_bit_test_cmp (const void *p1, const void *p2)
+{
+ const struct case_bit_test *const d1 = (const struct case_bit_test *) p1;
+ const struct case_bit_test *const d2 = (const struct case_bit_test *) p2;
+
+ if (d2->target_edge->count != d1->target_edge->count)
+ return d2->target_edge->count - d1->target_edge->count;
+ if (d2->bits != d1->bits)
+ return d2->bits - d1->bits;
+
+ /* Stabilize the sort. */
+ return LABEL_DECL_UID (d2->label) - LABEL_DECL_UID (d1->label);
+}
+
+/* Expand a switch statement by a short sequence of bit-wise
+ comparisons. "switch(x)" is effectively converted into
+ "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are
+ integer constants.
+
+ INDEX_EXPR is the value being switched on.
+
+ MINVAL is the lowest case value of in the case nodes,
+ and RANGE is highest value minus MINVAL. MINVAL and RANGE
+ are not guaranteed to be of the same type as INDEX_EXPR
+ (the gimplifier doesn't change the type of case label values,
+ and MINVAL and RANGE are derived from those values).
+ MAXVAL is MINVAL + RANGE.
+
+ There *MUST* be MAX_CASE_BIT_TESTS or less unique case
+ node targets. */
+
+static void
+emit_case_bit_tests (gswitch *swtch, tree index_expr,
+ tree minval, tree range, tree maxval)
+{
+ struct case_bit_test test[MAX_CASE_BIT_TESTS];
+ unsigned int i, j, k;
+ unsigned int count;
+
+ basic_block switch_bb = gimple_bb (swtch);
+ basic_block default_bb, new_default_bb, new_bb;
+ edge default_edge;
+ bool update_dom = dom_info_available_p (CDI_DOMINATORS);
+
+ vec<basic_block> bbs_to_fix_dom = vNULL;
+
+ tree index_type = TREE_TYPE (index_expr);
+ tree unsigned_index_type = unsigned_type_for (index_type);
+ unsigned int branch_num = gimple_switch_num_labels (swtch);
+
+ gimple_stmt_iterator gsi;
+ gassign *shift_stmt;
+
+ tree idx, tmp, csui;
+ tree word_type_node = lang_hooks.types.type_for_mode (word_mode, 1);
+ tree word_mode_zero = fold_convert (word_type_node, integer_zero_node);
+ tree word_mode_one = fold_convert (word_type_node, integer_one_node);
+ int prec = TYPE_PRECISION (word_type_node);
+ wide_int wone = wi::one (prec);
+
+ memset (&test, 0, sizeof (test));
+
+ /* Get the edge for the default case. */
+ tmp = gimple_switch_default_label (swtch);
+ default_bb = label_to_block (CASE_LABEL (tmp));
+ default_edge = find_edge (switch_bb, default_bb);
+
+ /* Go through all case labels, and collect the case labels, profile
+ counts, and other information we need to build the branch tests. */
+ count = 0;
+ for (i = 1; i < branch_num; i++)
+ {
+ unsigned int lo, hi;
+ tree cs = gimple_switch_label (swtch, i);
+ tree label = CASE_LABEL (cs);
+ edge e = find_edge (switch_bb, label_to_block (label));
+ for (k = 0; k < count; k++)
+ if (e == test[k].target_edge)
+ break;
+
+ if (k == count)
+ {
+ gcc_checking_assert (count < MAX_CASE_BIT_TESTS);
+ test[k].mask = wi::zero (prec);
+ test[k].target_edge = e;
+ test[k].label = label;
+ test[k].bits = 1;
+ count++;
+ }
+ else
+ test[k].bits++;
+
+ lo = tree_to_uhwi (int_const_binop (MINUS_EXPR,
+ CASE_LOW (cs), minval));
+ if (CASE_HIGH (cs) == NULL_TREE)
+ hi = lo;
+ else
+ hi = tree_to_uhwi (int_const_binop (MINUS_EXPR,
+ CASE_HIGH (cs), minval));
+
+ for (j = lo; j <= hi; j++)
+ test[k].mask |= wi::lshift (wone, j);
+ }
+
+ qsort (test, count, sizeof (*test), case_bit_test_cmp);
+
+ /* If all values are in the 0 .. BITS_PER_WORD-1 range, we can get rid of
+ the minval subtractions, but it might make the mask constants more
+ expensive. So, compare the costs. */
+ if (compare_tree_int (minval, 0) > 0
+ && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0)
+ {
+ int cost_diff;
+ HOST_WIDE_INT m = tree_to_uhwi (minval);
+ rtx reg = gen_raw_REG (word_mode, 10000);
+ bool speed_p = optimize_bb_for_speed_p (gimple_bb (swtch));
+ cost_diff = set_rtx_cost (gen_rtx_PLUS (word_mode, reg,
+ GEN_INT (-m)), speed_p);
+ for (i = 0; i < count; i++)
+ {
+ rtx r = immed_wide_int_const (test[i].mask, word_mode);
+ cost_diff += set_src_cost (gen_rtx_AND (word_mode, reg, r), speed_p);
+ r = immed_wide_int_const (wi::lshift (test[i].mask, m), word_mode);
+ cost_diff -= set_src_cost (gen_rtx_AND (word_mode, reg, r), speed_p);
+ }
+ if (cost_diff > 0)
+ {
+ for (i = 0; i < count; i++)
+ test[i].mask = wi::lshift (test[i].mask, m);
+ minval = build_zero_cst (TREE_TYPE (minval));
+ range = maxval;
+ }
+ }
+
+ /* We generate two jumps to the default case label.
+ Split the default edge, so that we don't have to do any PHI node
+ updating. */
+ new_default_bb = split_edge (default_edge);
+
+ if (update_dom)
+ {
+ bbs_to_fix_dom.create (10);
+ bbs_to_fix_dom.quick_push (switch_bb);
+ bbs_to_fix_dom.quick_push (default_bb);
+ bbs_to_fix_dom.quick_push (new_default_bb);
+ }
+
+ /* Now build the test-and-branch code. */
+
+ gsi = gsi_last_bb (switch_bb);
+
+ /* idx = (unsigned)x - minval. */
+ idx = fold_convert (unsigned_index_type, index_expr);
+ idx = fold_build2 (MINUS_EXPR, unsigned_index_type, idx,
+ fold_convert (unsigned_index_type, minval));
+ idx = force_gimple_operand_gsi (&gsi, idx,
+ /*simple=*/true, NULL_TREE,
+ /*before=*/true, GSI_SAME_STMT);
+
+ /* if (idx > range) goto default */
+ range = force_gimple_operand_gsi (&gsi,
+ fold_convert (unsigned_index_type, range),
+ /*simple=*/true, NULL_TREE,
+ /*before=*/true, GSI_SAME_STMT);
+ tmp = fold_build2 (GT_EXPR, boolean_type_node, idx, range);
+ new_bb = hoist_edge_and_branch_if_true (&gsi, tmp, default_edge, update_dom);
+ if (update_dom)
+ bbs_to_fix_dom.quick_push (new_bb);
+ gcc_assert (gimple_bb (swtch) == new_bb);
+ gsi = gsi_last_bb (new_bb);
+
+ /* Any blocks dominated by the GIMPLE_SWITCH, but that are not successors
+ of NEW_BB, are still immediately dominated by SWITCH_BB. Make it so. */
+ if (update_dom)
+ {
+ vec<basic_block> dom_bbs;
+ basic_block dom_son;
+
+ dom_bbs = get_dominated_by (CDI_DOMINATORS, new_bb);
+ FOR_EACH_VEC_ELT (dom_bbs, i, dom_son)
+ {
+ edge e = find_edge (new_bb, dom_son);
+ if (e && single_pred_p (e->dest))
+ continue;
+ set_immediate_dominator (CDI_DOMINATORS, dom_son, switch_bb);
+ bbs_to_fix_dom.safe_push (dom_son);
+ }
+ dom_bbs.release ();
+ }
+
+ /* csui = (1 << (word_mode) idx) */
+ csui = make_ssa_name (word_type_node);
+ tmp = fold_build2 (LSHIFT_EXPR, word_type_node, word_mode_one,
+ fold_convert (word_type_node, idx));
+ tmp = force_gimple_operand_gsi (&gsi, tmp,
+ /*simple=*/false, NULL_TREE,
+ /*before=*/true, GSI_SAME_STMT);
+ shift_stmt = gimple_build_assign (csui, tmp);
+ gsi_insert_before (&gsi, shift_stmt, GSI_SAME_STMT);
+ update_stmt (shift_stmt);
+
+ /* for each unique set of cases:
+ if (const & csui) goto target */
+ for (k = 0; k < count; k++)
+ {
+ tmp = wide_int_to_tree (word_type_node, test[k].mask);
+ tmp = fold_build2 (BIT_AND_EXPR, word_type_node, csui, tmp);
+ tmp = force_gimple_operand_gsi (&gsi, tmp,
+ /*simple=*/true, NULL_TREE,
+ /*before=*/true, GSI_SAME_STMT);
+ tmp = fold_build2 (NE_EXPR, boolean_type_node, tmp, word_mode_zero);
+ new_bb = hoist_edge_and_branch_if_true (&gsi, tmp, test[k].target_edge,
+ update_dom);
+ if (update_dom)
+ bbs_to_fix_dom.safe_push (new_bb);
+ gcc_assert (gimple_bb (swtch) == new_bb);
+ gsi = gsi_last_bb (new_bb);
+ }
+
+ /* We should have removed all edges now. */
+ gcc_assert (EDGE_COUNT (gsi_bb (gsi)->succs) == 0);
+
+ /* If nothing matched, go to the default label. */
+ make_edge (gsi_bb (gsi), new_default_bb, EDGE_FALLTHRU);
+
+ /* The GIMPLE_SWITCH is now redundant. */
+ gsi_remove (&gsi, true);
+
+ if (update_dom)
+ {
+ /* Fix up the dominator tree. */
+ iterate_fix_dominators (CDI_DOMINATORS, bbs_to_fix_dom, true);
+ bbs_to_fix_dom.release ();
+ }
+}
+\f
/*
Switch initialization conversion
The following pass changes simple initializations of scalars in a switch
-statement into initializations from a static array. Obviously, the values must
-be constant and known at compile time and a default branch must be
+statement into initializations from a static array. Obviously, the values
+must be constant and known at compile time and a default branch must be
provided. For example, the following code:
int a,b;
default:
a_4 = 16;
b_4 = 1;
+ break;
}
a_5 = PHI <a_1, a_2, a_3, a_4>
b_5 = PHI <b_1, b_2, b_3, b_4>
a_7 = 16;
b_7 = 1;
}
- b_b = PHI <b_6, b_7>
+ a_5 = PHI <a_6, a_7>
+ b_b = PHI <b_6, b_7>
There are further constraints. Specifically, the range of values across all
case labels must not be bigger than SWITCH_CONVERSION_BRANCH_RATIO (default
-eight) times the number of the actual switch branches. */
-
-#include "config.h"
-#include "system.h"
-#include "coretypes.h"
-#include "tm.h"
-#include <signal.h>
+eight) times the number of the actual switch branches.
-#include "line-map.h"
-#include "params.h"
-#include "flags.h"
-#include "tree.h"
-#include "basic-block.h"
-#include "tree-flow.h"
-#include "tree-flow-inline.h"
-#include "tree-ssa-operands.h"
-#include "output.h"
-#include "input.h"
-#include "tree-pass.h"
-#include "diagnostic.h"
-#include "tree-dump.h"
-#include "timevar.h"
+This transformation was contributed by Martin Jambor, see this e-mail:
+ http://gcc.gnu.org/ml/gcc-patches/2008-07/msg00011.html */
/* The main structure of the pass. */
struct switch_conv_info
{
- /* The expression used to decide the switch branch. (It is subsequently used
- as the index to the created array.) */
+ /* The expression used to decide the switch branch. */
tree index_expr;
- /* The following integer constants store the minimum value covered by the
- cases. */
+ /* The following integer constants store the minimum and maximum value
+ covered by the case labels. */
tree range_min;
+ tree range_max;
- /* The difference between the above two numbers, i.e. The size of the array
- that would have to be created by the transformation. */
+ /* The difference between the above two numbers. Stored here because it
+ is used in all the conversion heuristics, as well as for some of the
+ transformation, and it is expensive to re-compute it all the time. */
tree range_size;
- /* Basic block that contains the actual SWITCH_EXPR. */
+ /* Basic block that contains the actual GIMPLE_SWITCH. */
basic_block switch_bb;
- /* All branches of the switch statement must have a single successor stored in
- the following variable. */
+ /* Basic block that is the target of the default case. */
+ basic_block default_bb;
+
+ /* The single successor block of all branches out of the GIMPLE_SWITCH,
+ if such a block exists. Otherwise NULL. */
basic_block final_bb;
+ /* The probability of the default edge in the replaced switch. */
+ int default_prob;
+
+ /* The count of the default edge in the replaced switch. */
+ gcov_type default_count;
+
+ /* Combined count of all other (non-default) edges in the replaced switch. */
+ gcov_type other_count;
+
/* Number of phi nodes in the final bb (that we'll be replacing). */
int phi_count;
tree *default_values;
/* Constructors of new static arrays. */
- VEC (constructor_elt, gc) **constructors;
+ vec<constructor_elt, va_gc> **constructors;
/* Array of ssa names that are initialized with a value from a new static
array. */
switch expression is out of range. */
tree *target_outbound_names;
- /* The probability of the default edge in the replaced switch. */
- int default_prob;
-
- /* The count of the default edge in the replaced switch. */
- gcov_type default_count;
-
- /* Combined count of all other (non-default) edges in the replaced switch. */
- gcov_type other_count;
-
/* The first load statement that loads a temporary from a new static array.
*/
gimple arr_ref_first;
/* String reason why the case wasn't a good candidate that is written to the
dump file, if there is one. */
const char *reason;
-};
-
-/* Global pass info. */
-static struct switch_conv_info info;
+ /* Parameters for expand_switch_using_bit_tests. Should be computed
+ the same way as in expand_case. */
+ unsigned int uniq;
+ unsigned int count;
+};
-/* Checks whether the range given by individual case statements of the SWTCH
- switch statement isn't too big and whether the number of branches actually
- satisfies the size of the new array. */
+/* Collect information about GIMPLE_SWITCH statement SWTCH into INFO. */
-static bool
-check_range (gimple swtch)
+static void
+collect_switch_conv_info (gswitch *swtch, struct switch_conv_info *info)
{
- tree min_case, max_case;
unsigned int branch_num = gimple_switch_num_labels (swtch);
- tree range_max;
+ tree min_case, max_case;
+ unsigned int count, i;
+ edge e, e_default;
+ edge_iterator ei;
+
+ memset (info, 0, sizeof (*info));
/* The gimplifier has already sorted the cases by CASE_LOW and ensured there
- is a default label which is the last in the vector. */
+ is a default label which is the first in the vector.
+ Collect the bits we can deduce from the CFG. */
+ info->index_expr = gimple_switch_index (swtch);
+ info->switch_bb = gimple_bb (swtch);
+ info->default_bb =
+ label_to_block (CASE_LABEL (gimple_switch_default_label (swtch)));
+ e_default = find_edge (info->switch_bb, info->default_bb);
+ info->default_prob = e_default->probability;
+ info->default_count = e_default->count;
+ FOR_EACH_EDGE (e, ei, info->switch_bb->succs)
+ if (e != e_default)
+ info->other_count += e->count;
+
+ /* See if there is one common successor block for all branch
+ targets. If it exists, record it in FINAL_BB.
+ Start with the destination of the default case as guess
+ or its destination in case it is a forwarder block. */
+ if (! single_pred_p (e_default->dest))
+ info->final_bb = e_default->dest;
+ else if (single_succ_p (e_default->dest)
+ && ! single_pred_p (single_succ (e_default->dest)))
+ info->final_bb = single_succ (e_default->dest);
+ /* Require that all switch destinations are either that common
+ FINAL_BB or a forwarder to it. */
+ if (info->final_bb)
+ FOR_EACH_EDGE (e, ei, info->switch_bb->succs)
+ {
+ if (e->dest == info->final_bb)
+ continue;
- min_case = gimple_switch_label (swtch, 1);
- info.range_min = CASE_LOW (min_case);
+ if (single_pred_p (e->dest)
+ && single_succ_p (e->dest)
+ && single_succ (e->dest) == info->final_bb)
+ continue;
- gcc_assert (branch_num > 1);
- gcc_assert (CASE_LOW (gimple_switch_label (swtch, 0)) == NULL_TREE);
+ info->final_bb = NULL;
+ break;
+ }
+
+ /* Get upper and lower bounds of case values, and the covered range. */
+ min_case = gimple_switch_label (swtch, 1);
max_case = gimple_switch_label (swtch, branch_num - 1);
+
+ info->range_min = CASE_LOW (min_case);
if (CASE_HIGH (max_case) != NULL_TREE)
- range_max = CASE_HIGH (max_case);
+ info->range_max = CASE_HIGH (max_case);
else
- range_max = CASE_LOW (max_case);
+ info->range_max = CASE_LOW (max_case);
- gcc_assert (info.range_min);
- gcc_assert (range_max);
+ info->range_size =
+ int_const_binop (MINUS_EXPR, info->range_max, info->range_min);
- info.range_size = int_const_binop (MINUS_EXPR, range_max, info.range_min, 0);
+ /* Get a count of the number of case labels. Single-valued case labels
+ simply count as one, but a case range counts double, since it may
+ require two compares if it gets lowered as a branching tree. */
+ count = 0;
+ for (i = 1; i < branch_num; i++)
+ {
+ tree elt = gimple_switch_label (swtch, i);
+ count++;
+ if (CASE_HIGH (elt)
+ && ! tree_int_cst_equal (CASE_LOW (elt), CASE_HIGH (elt)))
+ count++;
+ }
+ info->count = count;
+
+ /* Get the number of unique non-default targets out of the GIMPLE_SWITCH
+ block. Assume a CFG cleanup would have already removed degenerate
+ switch statements, this allows us to just use EDGE_COUNT. */
+ info->uniq = EDGE_COUNT (gimple_bb (swtch)->succs) - 1;
+}
- gcc_assert (info.range_size);
- if (!host_integerp (info.range_size, 1))
+/* Checks whether the range given by individual case statements of the SWTCH
+ switch statement isn't too big and whether the number of branches actually
+ satisfies the size of the new array. */
+
+static bool
+check_range (struct switch_conv_info *info)
+{
+ gcc_assert (info->range_size);
+ if (!tree_fits_uhwi_p (info->range_size))
{
- info.reason = "index range way too large or otherwise unusable.\n";
+ info->reason = "index range way too large or otherwise unusable";
return false;
}
- if ((unsigned HOST_WIDE_INT) tree_low_cst (info.range_size, 1)
- > ((unsigned) branch_num * SWITCH_CONVERSION_BRANCH_RATIO))
+ if (tree_to_uhwi (info->range_size)
+ > ((unsigned) info->count * SWITCH_CONVERSION_BRANCH_RATIO))
{
- info.reason = "the maximum range-branch ratio exceeded.\n";
+ info->reason = "the maximum range-branch ratio exceeded";
return false;
}
return true;
}
-/* Checks the given CS switch case whether it is suitable for conversion
- (whether all but the default basic blocks are empty and so on). If it is,
- adds the case to the branch list along with values for the defined variables
- and returns true. Otherwise returns false. */
+/* Checks whether all but the FINAL_BB basic blocks are empty. */
static bool
-check_process_case (tree cs)
+check_all_empty_except_final (struct switch_conv_info *info)
{
- tree ldecl;
- basic_block label_bb, following_bb;
edge e;
+ edge_iterator ei;
- ldecl = CASE_LABEL (cs);
- label_bb = label_to_block (ldecl);
-
- e = find_edge (info.switch_bb, label_bb);
- gcc_assert (e);
-
- if (CASE_LOW (cs) == NULL_TREE)
- {
- /* Default branch. */
- info.default_prob = e->probability;
- info.default_count = e->count;
- }
- else
- info.other_count += e->count;
-
- if (!label_bb)
- {
- info.reason = " Bad case - cs BB label is NULL\n";
- return false;
- }
-
- if (!single_pred_p (label_bb))
+ FOR_EACH_EDGE (e, ei, info->switch_bb->succs)
{
- if (info.final_bb && info.final_bb != label_bb)
- {
- info.reason = " Bad case - a non-final BB has two predecessors\n";
- return false; /* sth complex going on in this branch */
- }
+ if (e->dest == info->final_bb)
+ continue;
- following_bb = label_bb;
- }
- else
- {
- if (!empty_block_p (label_bb))
+ if (!empty_block_p (e->dest))
{
- info.reason = " Bad case - a non-final BB not empty\n";
+ info->reason = "bad case - a non-final BB not empty";
return false;
}
-
- e = single_succ_edge (label_bb);
- following_bb = single_succ (label_bb);
- }
-
- if (!info.final_bb)
- info.final_bb = following_bb;
- else if (info.final_bb != following_bb)
- {
- info.reason = " Bad case - different final BB\n";
- return false; /* the only successor is not common for all the branches */
}
return true;
phi nodes are OK, otherwise false. */
static bool
-check_final_bb (void)
+check_final_bb (struct switch_conv_info *info)
{
- gimple_stmt_iterator gsi;
+ gphi_iterator gsi;
- info.phi_count = 0;
- for (gsi = gsi_start_phis (info.final_bb); !gsi_end_p (gsi); gsi_next (&gsi))
+ info->phi_count = 0;
+ for (gsi = gsi_start_phis (info->final_bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
- gimple phi = gsi_stmt (gsi);
+ gphi *phi = gsi.phi ();
unsigned int i;
- info.phi_count++;
+ info->phi_count++;
for (i = 0; i < gimple_phi_num_args (phi); i++)
{
basic_block bb = gimple_phi_arg_edge (phi, i)->src;
- if (bb == info.switch_bb
- || (single_pred_p (bb) && single_pred (bb) == info.switch_bb))
+ if (bb == info->switch_bb
+ || (single_pred_p (bb) && single_pred (bb) == info->switch_bb))
{
tree reloc, val;
val = gimple_phi_arg_def (phi, i);
if (!is_gimple_ip_invariant (val))
{
- info.reason = " Non-invariant value from a case\n";
+ info->reason = "non-invariant value from a case";
return false; /* Non-invariant argument. */
}
reloc = initializer_constant_valid_p (val, TREE_TYPE (val));
|| (!flag_pic && reloc == NULL_TREE))
{
if (reloc)
- info.reason
- = " Value from a case would need runtime relocations\n";
+ info->reason
+ = "value from a case would need runtime relocations";
else
- info.reason
- = " Value from a case is not a valid initializer\n";
+ info->reason
+ = "value from a case is not a valid initializer";
return false;
}
}
vectors that will become constructors of new arrays. */
static void
-create_temp_arrays (void)
+create_temp_arrays (struct switch_conv_info *info)
{
int i;
- info.default_values = (tree *) xcalloc (info.phi_count, sizeof (tree));
- info.constructors = (VEC (constructor_elt, gc) **) xcalloc (info.phi_count,
- sizeof (tree));
- info.target_inbound_names = (tree *) xcalloc (info.phi_count, sizeof (tree));
- info.target_outbound_names = (tree *) xcalloc (info.phi_count,
- sizeof (tree));
-
- for (i = 0; i < info.phi_count; i++)
- info.constructors[i]
- = VEC_alloc (constructor_elt, gc, tree_low_cst (info.range_size, 1) + 1);
+ info->default_values = XCNEWVEC (tree, info->phi_count * 3);
+ /* ??? Macros do not support multi argument templates in their
+ argument list. We create a typedef to work around that problem. */
+ typedef vec<constructor_elt, va_gc> *vec_constructor_elt_gc;
+ info->constructors = XCNEWVEC (vec_constructor_elt_gc, info->phi_count);
+ info->target_inbound_names = info->default_values + info->phi_count;
+ info->target_outbound_names = info->target_inbound_names + info->phi_count;
+ for (i = 0; i < info->phi_count; i++)
+ vec_alloc (info->constructors[i], tree_to_uhwi (info->range_size) + 1);
}
/* Free the arrays created by create_temp_arrays(). The vectors that are
already become constructors and must be preserved. */
static void
-free_temp_arrays (void)
+free_temp_arrays (struct switch_conv_info *info)
{
- free (info.constructors);
- free (info.default_values);
- free (info.target_inbound_names);
- free (info.target_outbound_names);
+ XDELETEVEC (info->constructors);
+ XDELETEVEC (info->default_values);
}
/* Populate the array of default values in the order of phi nodes.
DEFAULT_CASE is the CASE_LABEL_EXPR for the default switch branch. */
static void
-gather_default_values (tree default_case)
+gather_default_values (tree default_case, struct switch_conv_info *info)
{
- gimple_stmt_iterator gsi;
+ gphi_iterator gsi;
basic_block bb = label_to_block (CASE_LABEL (default_case));
edge e;
int i = 0;
gcc_assert (CASE_LOW (default_case) == NULL_TREE);
- if (bb == info.final_bb)
- e = find_edge (info.switch_bb, bb);
+ if (bb == info->final_bb)
+ e = find_edge (info->switch_bb, bb);
else
e = single_succ_edge (bb);
- for (gsi = gsi_start_phis (info.final_bb); !gsi_end_p (gsi); gsi_next (&gsi))
+ for (gsi = gsi_start_phis (info->final_bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
- gimple phi = gsi_stmt (gsi);
+ gphi *phi = gsi.phi ();
tree val = PHI_ARG_DEF_FROM_EDGE (phi, e);
gcc_assert (val);
- info.default_values[i++] = val;
+ info->default_values[i++] = val;
}
}
order of phi nodes. SWTCH is the switch statement being converted. */
static void
-build_constructors (gimple swtch)
+build_constructors (gswitch *swtch, struct switch_conv_info *info)
{
unsigned i, branch_num = gimple_switch_num_labels (swtch);
- tree pos = info.range_min;
+ tree pos = info->range_min;
for (i = 1; i < branch_num; i++)
{
basic_block bb = label_to_block (CASE_LABEL (cs));
edge e;
tree high;
- gimple_stmt_iterator gsi;
+ gphi_iterator gsi;
int j;
- if (bb == info.final_bb)
- e = find_edge (info.switch_bb, bb);
+ if (bb == info->final_bb)
+ e = find_edge (info->switch_bb, bb);
else
e = single_succ_edge (bb);
gcc_assert (e);
while (tree_int_cst_lt (pos, CASE_LOW (cs)))
{
int k;
- for (k = 0; k < info.phi_count; k++)
+ for (k = 0; k < info->phi_count; k++)
{
- constructor_elt *elt;
+ constructor_elt elt;
- elt = VEC_quick_push (constructor_elt,
- info.constructors[k], NULL);
- elt->index = int_const_binop (MINUS_EXPR, pos,
- info.range_min, 0);
- elt->value = info.default_values[k];
+ elt.index = int_const_binop (MINUS_EXPR, pos, info->range_min);
+ elt.value
+ = unshare_expr_without_location (info->default_values[k]);
+ info->constructors[k]->quick_push (elt);
}
- pos = int_const_binop (PLUS_EXPR, pos, integer_one_node, 0);
+ pos = int_const_binop (PLUS_EXPR, pos,
+ build_int_cst (TREE_TYPE (pos), 1));
}
gcc_assert (tree_int_cst_equal (pos, CASE_LOW (cs)));
high = CASE_HIGH (cs);
else
high = CASE_LOW (cs);
- for (gsi = gsi_start_phis (info.final_bb);
+ for (gsi = gsi_start_phis (info->final_bb);
!gsi_end_p (gsi); gsi_next (&gsi))
{
- gimple phi = gsi_stmt (gsi);
+ gphi *phi = gsi.phi ();
tree val = PHI_ARG_DEF_FROM_EDGE (phi, e);
tree low = CASE_LOW (cs);
pos = CASE_LOW (cs);
- do
+ do
{
- constructor_elt *elt;
+ constructor_elt elt;
- elt = VEC_quick_push (constructor_elt,
- info.constructors[j], NULL);
- elt->index = int_const_binop (MINUS_EXPR, pos, info.range_min, 0);
- elt->value = val;
+ elt.index = int_const_binop (MINUS_EXPR, pos, info->range_min);
+ elt.value = unshare_expr_without_location (val);
+ info->constructors[j]->quick_push (elt);
- pos = int_const_binop (PLUS_EXPR, pos, integer_one_node, 0);
- } while (!tree_int_cst_lt (high, pos) && tree_int_cst_lt (low, pos));
+ pos = int_const_binop (PLUS_EXPR, pos,
+ build_int_cst (TREE_TYPE (pos), 1));
+ } while (!tree_int_cst_lt (high, pos)
+ && tree_int_cst_lt (low, pos));
j++;
}
}
}
+/* If all values in the constructor vector are the same, return the value.
+ Otherwise return NULL_TREE. Not supposed to be called for empty
+ vectors. */
+
+static tree
+constructor_contains_same_values_p (vec<constructor_elt, va_gc> *vec)
+{
+ unsigned int i;
+ tree prev = NULL_TREE;
+ constructor_elt *elt;
+
+ FOR_EACH_VEC_SAFE_ELT (vec, i, elt)
+ {
+ if (!prev)
+ prev = elt->value;
+ else if (!operand_equal_p (elt->value, prev, OEP_ONLY_CONST))
+ return NULL_TREE;
+ }
+ return prev;
+}
+
+/* Return type which should be used for array elements, either TYPE,
+ or for integral type some smaller integral type that can still hold
+ all the constants. */
+
+static tree
+array_value_type (gswitch *swtch, tree type, int num,
+ struct switch_conv_info *info)
+{
+ unsigned int i, len = vec_safe_length (info->constructors[num]);
+ constructor_elt *elt;
+ machine_mode mode;
+ int sign = 0;
+ tree smaller_type;
+
+ if (!INTEGRAL_TYPE_P (type))
+ return type;
+
+ mode = GET_CLASS_NARROWEST_MODE (GET_MODE_CLASS (TYPE_MODE (type)));
+ if (GET_MODE_SIZE (TYPE_MODE (type)) <= GET_MODE_SIZE (mode))
+ return type;
+
+ if (len < (optimize_bb_for_size_p (gimple_bb (swtch)) ? 2 : 32))
+ return type;
+
+ FOR_EACH_VEC_SAFE_ELT (info->constructors[num], i, elt)
+ {
+ wide_int cst;
+
+ if (TREE_CODE (elt->value) != INTEGER_CST)
+ return type;
+
+ cst = elt->value;
+ while (1)
+ {
+ unsigned int prec = GET_MODE_BITSIZE (mode);
+ if (prec > HOST_BITS_PER_WIDE_INT)
+ return type;
+
+ if (sign >= 0 && cst == wi::zext (cst, prec))
+ {
+ if (sign == 0 && cst == wi::sext (cst, prec))
+ break;
+ sign = 1;
+ break;
+ }
+ if (sign <= 0 && cst == wi::sext (cst, prec))
+ {
+ sign = -1;
+ break;
+ }
+
+ if (sign == 1)
+ sign = 0;
+
+ mode = GET_MODE_WIDER_MODE (mode);
+ if (mode == VOIDmode
+ || GET_MODE_SIZE (mode) >= GET_MODE_SIZE (TYPE_MODE (type)))
+ return type;
+ }
+ }
+
+ if (sign == 0)
+ sign = TYPE_UNSIGNED (type) ? 1 : -1;
+ smaller_type = lang_hooks.types.type_for_mode (mode, sign >= 0);
+ if (GET_MODE_SIZE (TYPE_MODE (type))
+ <= GET_MODE_SIZE (TYPE_MODE (smaller_type)))
+ return type;
+
+ return smaller_type;
+}
+
/* Create an appropriate array type and declaration and assemble a static array
variable. Also create a load statement that initializes the variable in
question with a value from the static array. SWTCH is the switch statement
and target SSA names for this particular array. ARR_INDEX_TYPE is the type
of the index of the new array, PHI is the phi node of the final BB that
corresponds to the value that will be loaded from the created array. TIDX
- is a temporary variable holding the index for loads from the new array. */
+ is an ssa name of a temporary variable holding the index for loads from the
+ new array. */
static void
-build_one_array (gimple swtch, int num, tree arr_index_type, gimple phi,
- tree tidx)
+build_one_array (gswitch *swtch, int num, tree arr_index_type,
+ gphi *phi, tree tidx, struct switch_conv_info *info)
{
- tree array_type, ctor, decl, value_type, name, fetch;
+ tree name, cst;
gimple load;
- gimple_stmt_iterator gsi;
-
- gcc_assert (info.default_values[num]);
- value_type = TREE_TYPE (info.default_values[num]);
- array_type = build_array_type (value_type, arr_index_type);
+ gimple_stmt_iterator gsi = gsi_for_stmt (swtch);
+ location_t loc = gimple_location (swtch);
- ctor = build_constructor (array_type, info.constructors[num]);
- TREE_CONSTANT (ctor) = true;
+ gcc_assert (info->default_values[num]);
- decl = build_decl (VAR_DECL, NULL_TREE, array_type);
- TREE_STATIC (decl) = 1;
- DECL_INITIAL (decl) = ctor;
+ name = copy_ssa_name (PHI_RESULT (phi));
+ info->target_inbound_names[num] = name;
- DECL_NAME (decl) = create_tmp_var_name ("CSWTCH");
- DECL_ARTIFICIAL (decl) = 1;
- TREE_CONSTANT (decl) = 1;
- add_referenced_var (decl);
- varpool_mark_needed_node (varpool_node (decl));
- varpool_finalize_decl (decl);
- mark_sym_for_renaming (decl);
+ cst = constructor_contains_same_values_p (info->constructors[num]);
+ if (cst)
+ load = gimple_build_assign (name, cst);
+ else
+ {
+ tree array_type, ctor, decl, value_type, fetch, default_type;
- name = make_ssa_name (SSA_NAME_VAR (PHI_RESULT (phi)), NULL);
- info.target_inbound_names[num] = name;
+ default_type = TREE_TYPE (info->default_values[num]);
+ value_type = array_value_type (swtch, default_type, num, info);
+ array_type = build_array_type (value_type, arr_index_type);
+ if (default_type != value_type)
+ {
+ unsigned int i;
+ constructor_elt *elt;
- fetch = build4 (ARRAY_REF, value_type, decl, tidx, NULL_TREE,
- NULL_TREE);
- load = gimple_build_assign (name, fetch);
- SSA_NAME_DEF_STMT (name) = load;
+ FOR_EACH_VEC_SAFE_ELT (info->constructors[num], i, elt)
+ elt->value = fold_convert (value_type, elt->value);
+ }
+ ctor = build_constructor (array_type, info->constructors[num]);
+ TREE_CONSTANT (ctor) = true;
+ TREE_STATIC (ctor) = true;
+
+ decl = build_decl (loc, VAR_DECL, NULL_TREE, array_type);
+ TREE_STATIC (decl) = 1;
+ DECL_INITIAL (decl) = ctor;
+
+ DECL_NAME (decl) = create_tmp_var_name ("CSWTCH");
+ DECL_ARTIFICIAL (decl) = 1;
+ DECL_IGNORED_P (decl) = 1;
+ TREE_CONSTANT (decl) = 1;
+ TREE_READONLY (decl) = 1;
+ DECL_IGNORED_P (decl) = 1;
+ varpool_node::finalize_decl (decl);
+
+ fetch = build4 (ARRAY_REF, value_type, decl, tidx, NULL_TREE,
+ NULL_TREE);
+ if (default_type != value_type)
+ {
+ fetch = fold_convert (default_type, fetch);
+ fetch = force_gimple_operand_gsi (&gsi, fetch, true, NULL_TREE,
+ true, GSI_SAME_STMT);
+ }
+ load = gimple_build_assign (name, fetch);
+ }
- gsi = gsi_for_stmt (swtch);
gsi_insert_before (&gsi, load, GSI_SAME_STMT);
- mark_symbols_for_renaming (load);
-
- info.arr_ref_last = load;
+ update_stmt (load);
+ info->arr_ref_last = load;
}
/* Builds and initializes static arrays initialized with values gathered from
them. */
static void
-build_arrays (gimple swtch)
+build_arrays (gswitch *swtch, struct switch_conv_info *info)
{
tree arr_index_type;
- tree tidx, sub;
+ tree tidx, sub, utype;
gimple stmt;
gimple_stmt_iterator gsi;
+ gphi_iterator gpi;
int i;
+ location_t loc = gimple_location (swtch);
gsi = gsi_for_stmt (swtch);
- arr_index_type = build_index_type (info.range_size);
- tidx = make_rename_temp (arr_index_type, "csti");
- sub = fold_build2 (MINUS_EXPR, TREE_TYPE (info.index_expr), info.index_expr,
- fold_convert (TREE_TYPE (info.index_expr),
- info.range_min));
- sub = force_gimple_operand_gsi (&gsi, fold_convert (arr_index_type, sub),
+ /* Make sure we do not generate arithmetics in a subrange. */
+ utype = TREE_TYPE (info->index_expr);
+ if (TREE_TYPE (utype))
+ utype = lang_hooks.types.type_for_mode (TYPE_MODE (TREE_TYPE (utype)), 1);
+ else
+ utype = lang_hooks.types.type_for_mode (TYPE_MODE (utype), 1);
+
+ arr_index_type = build_index_type (info->range_size);
+ tidx = make_ssa_name (utype);
+ sub = fold_build2_loc (loc, MINUS_EXPR, utype,
+ fold_convert_loc (loc, utype, info->index_expr),
+ fold_convert_loc (loc, utype, info->range_min));
+ sub = force_gimple_operand_gsi (&gsi, sub,
false, NULL, true, GSI_SAME_STMT);
stmt = gimple_build_assign (tidx, sub);
gsi_insert_before (&gsi, stmt, GSI_SAME_STMT);
- mark_symbols_for_renaming (stmt);
- info.arr_ref_first = stmt;
+ update_stmt (stmt);
+ info->arr_ref_first = stmt;
- for (gsi = gsi_start_phis (info.final_bb), i = 0;
- !gsi_end_p (gsi); gsi_next (&gsi), i++)
- build_one_array (swtch, i, arr_index_type, gsi_stmt (gsi), tidx);
+ for (gpi = gsi_start_phis (info->final_bb), i = 0;
+ !gsi_end_p (gpi); gsi_next (&gpi), i++)
+ build_one_array (swtch, i, arr_index_type, gpi.phi (), tidx, info);
}
/* Generates and appropriately inserts loads of default values at the position
given by BSI. Returns the last inserted statement. */
-static gimple
-gen_def_assigns (gimple_stmt_iterator *gsi)
+static gassign *
+gen_def_assigns (gimple_stmt_iterator *gsi, struct switch_conv_info *info)
{
int i;
- gimple assign = NULL;
+ gassign *assign = NULL;
- for (i = 0; i < info.phi_count; i++)
+ for (i = 0; i < info->phi_count; i++)
{
- tree name
- = make_ssa_name (SSA_NAME_VAR (info.target_inbound_names[i]), NULL);
-
- info.target_outbound_names[i] = name;
- assign = gimple_build_assign (name, info.default_values[i]);
- SSA_NAME_DEF_STMT (name) = assign;
+ tree name = copy_ssa_name (info->target_inbound_names[i]);
+ info->target_outbound_names[i] = name;
+ assign = gimple_build_assign (name, info->default_values[i]);
gsi_insert_before (gsi, assign, GSI_SAME_STMT);
- find_new_referenced_vars (assign);
- mark_symbols_for_renaming (assign);
+ update_stmt (assign);
}
return assign;
}
bbf description in the comment below). */
static void
-fix_phi_nodes (edge e1f, edge e2f, basic_block bbf)
+fix_phi_nodes (edge e1f, edge e2f, basic_block bbf,
+ struct switch_conv_info *info)
{
- gimple_stmt_iterator gsi;
+ gphi_iterator gsi;
int i;
for (gsi = gsi_start_phis (bbf), i = 0;
!gsi_end_p (gsi); gsi_next (&gsi), i++)
{
- gimple phi = gsi_stmt (gsi);
- add_phi_arg (phi, info.target_inbound_names[i], e1f);
- add_phi_arg (phi, info.target_outbound_names[i], e2f);
+ gphi *phi = gsi.phi ();
+ add_phi_arg (phi, info->target_inbound_names[i], e1f, UNKNOWN_LOCATION);
+ add_phi_arg (phi, info->target_outbound_names[i], e2f, UNKNOWN_LOCATION);
}
-
}
/* Creates a check whether the switch expression value actually falls into the
*/
static void
-gen_inbound_check (gimple swtch)
+gen_inbound_check (gswitch *swtch, struct switch_conv_info *info)
{
- tree label_decl1 = create_artificial_label ();
- tree label_decl2 = create_artificial_label ();
- tree label_decl3 = create_artificial_label ();
- gimple label1, label2, label3;
-
- tree utype;
- tree tmp_u;
- tree cast;
- gimple cast_assign, minus_assign;
- tree ulb, minus;
+ tree label_decl1 = create_artificial_label (UNKNOWN_LOCATION);
+ tree label_decl2 = create_artificial_label (UNKNOWN_LOCATION);
+ tree label_decl3 = create_artificial_label (UNKNOWN_LOCATION);
+ glabel *label1, *label2, *label3;
+ tree utype, tidx;
tree bound;
- gimple cond_stmt;
+ gcond *cond_stmt;
- gimple last_assign;
+ gassign *last_assign;
gimple_stmt_iterator gsi;
basic_block bb0, bb1, bb2, bbf, bbd;
edge e01, e02, e21, e1d, e1f, e2f;
+ location_t loc = gimple_location (swtch);
+
+ gcc_assert (info->default_values);
- gcc_assert (info.default_values);
bb0 = gimple_bb (swtch);
- /* Make sure we do not generate arithmetics in a subrange. */
- if (TREE_TYPE (TREE_TYPE (info.index_expr)))
- utype = unsigned_type_for (TREE_TYPE (TREE_TYPE (info.index_expr)));
- else
- utype = unsigned_type_for (TREE_TYPE (info.index_expr));
+ tidx = gimple_assign_lhs (info->arr_ref_first);
+ utype = TREE_TYPE (tidx);
/* (end of) block 0 */
- gsi = gsi_for_stmt (info.arr_ref_first);
- tmp_u = make_rename_temp (utype, "csui");
-
- cast = fold_convert (utype, info.index_expr);
- cast_assign = gimple_build_assign (tmp_u, cast);
- find_new_referenced_vars (cast_assign);
- gsi_insert_before (&gsi, cast_assign, GSI_SAME_STMT);
- mark_symbols_for_renaming (cast_assign);
-
- ulb = fold_convert (utype, info.range_min);
- minus = fold_build2 (MINUS_EXPR, utype, tmp_u, ulb);
- minus = force_gimple_operand_gsi (&gsi, minus, false, NULL, true,
- GSI_SAME_STMT);
- minus_assign = gimple_build_assign (tmp_u, minus);
- find_new_referenced_vars (minus_assign);
- gsi_insert_before (&gsi, minus_assign, GSI_SAME_STMT);
- mark_symbols_for_renaming (minus_assign);
-
- bound = fold_convert (utype, info.range_size);
+ gsi = gsi_for_stmt (info->arr_ref_first);
+ gsi_next (&gsi);
- cond_stmt = gimple_build_cond (LE_EXPR, tmp_u, bound, NULL_TREE, NULL_TREE);
-
- find_new_referenced_vars (cond_stmt);
+ bound = fold_convert_loc (loc, utype, info->range_size);
+ cond_stmt = gimple_build_cond (LE_EXPR, tidx, bound, NULL_TREE, NULL_TREE);
gsi_insert_before (&gsi, cond_stmt, GSI_SAME_STMT);
- mark_symbols_for_renaming (cond_stmt);
+ update_stmt (cond_stmt);
/* block 2 */
- gsi = gsi_for_stmt (info.arr_ref_first);
label2 = gimple_build_label (label_decl2);
gsi_insert_before (&gsi, label2, GSI_SAME_STMT);
- last_assign = gen_def_assigns (&gsi);
+ last_assign = gen_def_assigns (&gsi, info);
/* block 1 */
- gsi = gsi_for_stmt (info.arr_ref_first);
label1 = gimple_build_label (label_decl1);
gsi_insert_before (&gsi, label1, GSI_SAME_STMT);
/* block F */
- gsi = gsi_start_bb (info.final_bb);
+ gsi = gsi_start_bb (info->final_bb);
label3 = gimple_build_label (label_decl3);
gsi_insert_before (&gsi, label3, GSI_SAME_STMT);
bb1 = e21->dest;
remove_edge (e21);
- e1d = split_block (bb1, info.arr_ref_last);
+ e1d = split_block (bb1, info->arr_ref_last);
bbd = e1d->dest;
remove_edge (e1d);
/* flags and profiles of the edge for in-range values */
e01 = make_edge (bb0, bb1, EDGE_TRUE_VALUE);
- e01->probability = REG_BR_PROB_BASE - info.default_prob;
- e01->count = info.other_count;
+ e01->probability = REG_BR_PROB_BASE - info->default_prob;
+ e01->count = info->other_count;
/* flags and profiles of the edge taking care of out-of-range values */
e02->flags &= ~EDGE_FALLTHRU;
e02->flags |= EDGE_FALSE_VALUE;
- e02->probability = info.default_prob;
- e02->count = info.default_count;
+ e02->probability = info->default_prob;
+ e02->count = info->default_count;
- bbf = info.final_bb;
+ bbf = info->final_bb;
e1f = make_edge (bb1, bbf, EDGE_FALLTHRU);
e1f->probability = REG_BR_PROB_BASE;
- e1f->count = info.other_count;
+ e1f->count = info->other_count;
e2f = make_edge (bb2, bbf, EDGE_FALLTHRU);
e2f->probability = REG_BR_PROB_BASE;
- e2f->count = info.default_count;
+ e2f->count = info->default_count;
/* frequencies of the new BBs */
bb1->frequency = EDGE_FREQUENCY (e01);
bb2->frequency = EDGE_FREQUENCY (e02);
bbf->frequency = EDGE_FREQUENCY (e1f) + EDGE_FREQUENCY (e2f);
- prune_bbs (bbd, info.final_bb); /* To keep calc_dfs_tree() in dominance.c
- happy. */
+ /* Tidy blocks that have become unreachable. */
+ prune_bbs (bbd, info->final_bb);
- fix_phi_nodes (e1f, e2f, bbf);
+ /* Fixup the PHI nodes in bbF. */
+ fix_phi_nodes (e1f, e2f, bbf, info);
- free_dominance_info (CDI_DOMINATORS);
- free_dominance_info (CDI_POST_DOMINATORS);
+ /* Fix the dominator tree, if it is available. */
+ if (dom_info_available_p (CDI_DOMINATORS))
+ {
+ vec<basic_block> bbs_to_fix_dom;
+
+ set_immediate_dominator (CDI_DOMINATORS, bb1, bb0);
+ set_immediate_dominator (CDI_DOMINATORS, bb2, bb0);
+ if (! get_immediate_dominator (CDI_DOMINATORS, bbf))
+ /* If bbD was the immediate dominator ... */
+ set_immediate_dominator (CDI_DOMINATORS, bbf, bb0);
+
+ bbs_to_fix_dom.create (4);
+ bbs_to_fix_dom.quick_push (bb0);
+ bbs_to_fix_dom.quick_push (bb1);
+ bbs_to_fix_dom.quick_push (bb2);
+ bbs_to_fix_dom.quick_push (bbf);
+
+ iterate_fix_dominators (CDI_DOMINATORS, bbs_to_fix_dom, true);
+ bbs_to_fix_dom.release ();
+ }
}
/* The following function is invoked on every switch statement (the current one
is given in SWTCH) and runs the individual phases of switch conversion on it
- one after another until one fails or the conversion is completed. */
+ one after another until one fails or the conversion is completed.
+ Returns NULL on success, or a pointer to a string with the reason why the
+ conversion failed. */
-static bool
-process_switch (gimple swtch)
+static const char *
+process_switch (gswitch *swtch)
{
- unsigned int i, branch_num = gimple_switch_num_labels (swtch);
- tree index_type;
+ struct switch_conv_info info;
- /* Operand 2 is either NULL_TREE or a vector of cases (stmt.c). */
- if (branch_num < 2)
- {
- info.reason = "switch has no labels\n";
- return false;
- }
+ /* Group case labels so that we get the right results from the heuristics
+ that decide on the code generation approach for this switch. */
+ group_case_labels_stmt (swtch);
+
+ /* If this switch is now a degenerate case with only a default label,
+ there is nothing left for us to do. */
+ if (gimple_switch_num_labels (swtch) < 2)
+ return "switch is a degenerate case";
+
+ collect_switch_conv_info (swtch, &info);
- info.final_bb = NULL;
- info.switch_bb = gimple_bb (swtch);
- info.index_expr = gimple_switch_index (swtch);
- index_type = TREE_TYPE (info.index_expr);
- info.arr_ref_first = NULL;
- info.arr_ref_last = NULL;
- info.default_prob = 0;
- info.default_count = 0;
- info.other_count = 0;
-
- /* An ERROR_MARK occurs for various reasons including invalid data type.
- (comment from stmt.c) */
- if (index_type == error_mark_node)
+ /* No error markers should reach here (they should be filtered out
+ during gimplification). */
+ gcc_checking_assert (TREE_TYPE (info.index_expr) != error_mark_node);
+
+ /* A switch on a constant should have been optimized in tree-cfg-cleanup. */
+ gcc_checking_assert (! TREE_CONSTANT (info.index_expr));
+
+ if (info.uniq <= MAX_CASE_BIT_TESTS)
{
- info.reason = "index error.\n";
- return false;
+ if (expand_switch_using_bit_tests_p (info.range_size,
+ info.uniq, info.count,
+ optimize_bb_for_speed_p
+ (gimple_bb (swtch))))
+ {
+ if (dump_file)
+ fputs (" expanding as bit test is preferable\n", dump_file);
+ emit_case_bit_tests (swtch, info.index_expr, info.range_min,
+ info.range_size, info.range_max);
+ loops_state_set (LOOPS_NEED_FIXUP);
+ return NULL;
+ }
+
+ if (info.uniq <= 2)
+ /* This will be expanded as a decision tree in stmt.c:expand_case. */
+ return " expanding as jumps is preferable";
}
+ /* If there is no common successor, we cannot do the transformation. */
+ if (! info.final_bb)
+ return "no common successor to all case label target blocks found";
+
/* Check the case label values are within reasonable range: */
- if (!check_range (swtch))
- return false;
+ if (!check_range (&info))
+ {
+ gcc_assert (info.reason);
+ return info.reason;
+ }
/* For all the cases, see whether they are empty, the assignments they
represent constant and so on... */
- for (i = 0; i < branch_num; i++)
- if (!check_process_case (gimple_switch_label (swtch, i)))
- {
- if (dump_file)
- fprintf (dump_file, "Processing of case %i failed\n", i);
- return false;
- }
-
- if (!check_final_bb ())
- return false;
+ if (! check_all_empty_except_final (&info))
+ {
+ gcc_assert (info.reason);
+ return info.reason;
+ }
+ if (!check_final_bb (&info))
+ {
+ gcc_assert (info.reason);
+ return info.reason;
+ }
/* At this point all checks have passed and we can proceed with the
transformation. */
- create_temp_arrays ();
- gather_default_values (gimple_switch_label (swtch, 0));
- build_constructors (swtch);
+ create_temp_arrays (&info);
+ gather_default_values (gimple_switch_default_label (swtch), &info);
+ build_constructors (swtch, &info);
- build_arrays (swtch); /* Build the static arrays and assignments. */
- gen_inbound_check (swtch); /* Build the bounds check. */
+ build_arrays (swtch, &info); /* Build the static arrays and assignments. */
+ gen_inbound_check (swtch, &info); /* Build the bounds check. */
/* Cleanup: */
- free_temp_arrays ();
- return true;
+ free_temp_arrays (&info);
+ return NULL;
}
/* The main function of the pass scans statements for switches and invokes
process_switch on them. */
-static unsigned int
-do_switchconv (void)
+namespace {
+
+const pass_data pass_data_convert_switch =
+{
+ GIMPLE_PASS, /* type */
+ "switchconv", /* name */
+ OPTGROUP_NONE, /* optinfo_flags */
+ TV_TREE_SWITCH_CONVERSION, /* tv_id */
+ ( PROP_cfg | PROP_ssa ), /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_update_ssa, /* todo_flags_finish */
+};
+
+class pass_convert_switch : public gimple_opt_pass
+{
+public:
+ pass_convert_switch (gcc::context *ctxt)
+ : gimple_opt_pass (pass_data_convert_switch, ctxt)
+ {}
+
+ /* opt_pass methods: */
+ virtual bool gate (function *) { return flag_tree_switch_conversion != 0; }
+ virtual unsigned int execute (function *);
+
+}; // class pass_convert_switch
+
+unsigned int
+pass_convert_switch::execute (function *fun)
{
basic_block bb;
- FOR_EACH_BB (bb)
+ FOR_EACH_BB_FN (bb, fun)
{
+ const char *failure_reason;
gimple stmt = last_stmt (bb);
if (stmt && gimple_code (stmt) == GIMPLE_SWITCH)
{
"SWITCH statement (%s:%d) : ------- \n",
loc.file, loc.line);
print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
- fprintf (dump_file, "\n");
+ putc ('\n', dump_file);
}
- info.reason = NULL;
- if (process_switch (stmt))
+ failure_reason = process_switch (as_a <gswitch *> (stmt));
+ if (! failure_reason)
{
if (dump_file)
{
- fprintf (dump_file, "Switch converted\n");
- fprintf (dump_file, "--------------------------------\n");
+ fputs ("Switch converted\n", dump_file);
+ fputs ("--------------------------------\n", dump_file);
}
+
+ /* Make no effort to update the post-dominator tree. It is actually not
+ that hard for the transformations we have performed, but it is not
+ supported by iterate_fix_dominators. */
+ free_dominance_info (CDI_POST_DOMINATORS);
}
else
{
if (dump_file)
{
- gcc_assert (info.reason);
- fprintf (dump_file, "Bailing out - ");
- fprintf (dump_file, info.reason);
- fprintf (dump_file, "--------------------------------\n");
+ fputs ("Bailing out - ", dump_file);
+ fputs (failure_reason, dump_file);
+ fputs ("\n--------------------------------\n", dump_file);
}
}
}
return 0;
}
-/* The pass gate. */
+} // anon namespace
-static bool
-switchconv_gate (void)
+gimple_opt_pass *
+make_pass_convert_switch (gcc::context *ctxt)
{
- return flag_tree_switch_conversion != 0;
+ return new pass_convert_switch (ctxt);
}
-
-struct gimple_opt_pass pass_convert_switch =
-{
- {
- GIMPLE_PASS,
- "switchconv", /* name */
- switchconv_gate, /* gate */
- do_switchconv, /* execute */
- NULL, /* sub */
- NULL, /* next */
- 0, /* static_pass_number */
- TV_TREE_SWITCH_CONVERSION, /* tv_id */
- PROP_cfg | PROP_ssa, /* properties_required */
- 0, /* properties_provided */
- 0, /* properties_destroyed */
- 0, /* todo_flags_start */
- TODO_update_ssa | TODO_dump_func
- | TODO_ggc_collect | TODO_verify_ssa /* todo_flags_finish */
- }
-};
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