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re PR tree-optimization/57521 (wrong code for expressions in loop at -O3)
2013-08-27 Richard Biener <rguenther@suse.de> PR tree-optimization/57521 * tree-if-conv.c (if_convertible_bb_p): Verify that at least one edge is non-critical. (find_phi_replacement_condition): Make sure to use a non-critical edge. Cleanup and remove old bug workarounds. (bb_postdominates_preds): Remove. (if_convertible_loop_p_1): Do not compute post-dominators. (combine_blocks): Do not free post-dominators. (main_tree_if_conversion): Likewise. (pass_data_if_conversion): Add TODO_verify_ssa. * gcc.dg/torture/pr57521.c: New testcase. From-SVN: r202019
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Richard Biener
Richard Biener
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@ -1,3 +1,16 @@
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2013-08-27 Richard Biener <rguenther@suse.de>
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PR tree-optimization/57521
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* tree-if-conv.c (if_convertible_bb_p): Verify that at least
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one edge is non-critical.
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(find_phi_replacement_condition): Make sure to use a non-critical
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edge. Cleanup and remove old bug workarounds.
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(bb_postdominates_preds): Remove.
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(if_convertible_loop_p_1): Do not compute post-dominators.
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(combine_blocks): Do not free post-dominators.
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(main_tree_if_conversion): Likewise.
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(pass_data_if_conversion): Add TODO_verify_ssa.
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2013-08-27 DJ Delorie <dj@redhat.com>
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* config/i386/djgpp.h (ASM_DECLARE_FUNCTION_NAME): New.
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@ -1,3 +1,8 @@
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2013-08-27 Richard Biener <rguenther@suse.de>
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PR tree-optimization/57521
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* gcc.dg/torture/pr57521.c: New testcase.
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2013-08-27 Jakub Jelinek <jakub@redhat.com>
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PR rtl-optimization/57860
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51
gcc/testsuite/gcc.dg/torture/pr57521.c
Normal file
51
gcc/testsuite/gcc.dg/torture/pr57521.c
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@ -0,0 +1,51 @@
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/* { dg-do run } */
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/* { dg-options "-ftree-loop-if-convert" } */
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void abort (void);
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int a, b, c, d, o = 1, p;
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short e;
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int
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fn1 (int * p1)
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{
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int f, g, h, j = 0, k = 0, l = 0;
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unsigned int i;
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int *m[1] = { &l };
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for (; b >= 0; b--)
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{
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if (*p1)
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if (j >= 0)
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{
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int n = 1;
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e = 1;
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h = a ? a : 1 % n;
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g = h > 0 ? 0 : h + 1;
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k = c + g;
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}
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else
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continue;
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else
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{
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f = d > 0 ? 0 : d + 1;
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i = f;
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j = 1 + i;
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}
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l++;
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}
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return k;
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}
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int
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main ()
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{
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for (;; p++)
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{
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fn1 (&o);
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break;
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}
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if (e != 1)
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abort ();
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return 0;
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}
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@ -797,20 +797,6 @@ if_convertible_stmt_p (gimple stmt, vec<data_reference_p> refs)
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return true;
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}
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/* Return true when BB post-dominates all its predecessors. */
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static bool
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bb_postdominates_preds (basic_block bb)
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{
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unsigned i;
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for (i = 0; i < EDGE_COUNT (bb->preds); i++)
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if (!dominated_by_p (CDI_POST_DOMINATORS, EDGE_PRED (bb, i)->src, bb))
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return false;
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return true;
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}
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/* Return true when BB is if-convertible. This routine does not check
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basic block's statements and phis.
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@ -868,10 +854,23 @@ if_convertible_bb_p (struct loop *loop, basic_block bb, basic_block exit_bb)
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return false;
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}
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if (EDGE_COUNT (bb->preds) == 2
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&& bb != loop->header
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&& !bb_postdominates_preds (bb))
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return false;
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/* At least one incoming edge has to be non-critical as otherwise edge
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predicates are not equal to basic-block predicates of the edge
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source. */
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if (EDGE_COUNT (bb->preds) > 1
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&& bb != loop->header)
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{
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bool found = false;
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FOR_EACH_EDGE (e, ei, bb->preds)
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if (EDGE_COUNT (e->src->succs) == 1)
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found = true;
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if (!found)
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{
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if (dump_file && (dump_flags & TDF_DETAILS))
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fprintf (dump_file, "only critical predecessors\n");
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return false;
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}
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}
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return true;
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}
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@ -1084,7 +1083,6 @@ if_convertible_loop_p_1 (struct loop *loop,
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return false;
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calculate_dominance_info (CDI_DOMINATORS);
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calculate_dominance_info (CDI_POST_DOMINATORS);
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/* Allow statements that can be handled during if-conversion. */
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ifc_bbs = get_loop_body_in_if_conv_order (loop);
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@ -1220,8 +1218,7 @@ if_convertible_loop_p (struct loop *loop)
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if-conversion. */
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static basic_block
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find_phi_replacement_condition (struct loop *loop,
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basic_block bb, tree *cond,
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find_phi_replacement_condition (basic_block bb, tree *cond,
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gimple_stmt_iterator *gsi)
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{
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edge first_edge, second_edge;
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@ -1231,34 +1228,10 @@ find_phi_replacement_condition (struct loop *loop,
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first_edge = EDGE_PRED (bb, 0);
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second_edge = EDGE_PRED (bb, 1);
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/* Use condition based on following criteria:
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1)
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S1: x = !c ? a : b;
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S2: x = c ? b : a;
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S2 is preferred over S1. Make 'b' first_bb and use its condition.
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2) Do not make loop header first_bb.
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3)
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S1: x = !(c == d)? a : b;
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S21: t1 = c == d;
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S22: x = t1 ? b : a;
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S3: x = (c == d) ? b : a;
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S3 is preferred over S1 and S2*, Make 'b' first_bb and use
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its condition.
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4) If pred B is dominated by pred A then use pred B's condition.
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See PR23115. */
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/* Select condition that is not TRUTH_NOT_EXPR. */
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/* Prefer an edge with a not negated predicate.
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??? That's a very weak cost model. */
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tmp_cond = bb_predicate (first_edge->src);
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gcc_assert (tmp_cond);
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if (TREE_CODE (tmp_cond) == TRUTH_NOT_EXPR)
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{
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edge tmp_edge;
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@ -1268,11 +1241,9 @@ find_phi_replacement_condition (struct loop *loop,
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second_edge = tmp_edge;
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}
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/* Check if FIRST_BB is loop header or not and make sure that
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FIRST_BB does not dominate SECOND_BB. */
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if (first_edge->src == loop->header
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|| dominated_by_p (CDI_DOMINATORS,
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second_edge->src, first_edge->src))
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/* Check if the edge we take the condition from is not critical.
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We know that at least one non-critical edge exists. */
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if (EDGE_COUNT (first_edge->src->succs) > 1)
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{
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*cond = bb_predicate (second_edge->src);
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@ -1347,9 +1318,6 @@ predicate_scalar_phi (gimple phi, tree cond,
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arg_1 = gimple_phi_arg_def (phi, 1);
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}
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gcc_checking_assert (bb == bb->loop_father->header
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|| bb_postdominates_preds (bb));
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/* Build new RHS using selected condition and arguments. */
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rhs = fold_build_cond_expr (TREE_TYPE (res), unshare_expr (cond),
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arg_0, arg_1);
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@ -1395,7 +1363,7 @@ predicate_all_scalar_phis (struct loop *loop)
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/* BB has two predecessors. Using predecessor's aux field, set
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appropriate condition for the PHI node replacement. */
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gsi = gsi_after_labels (bb);
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true_bb = find_phi_replacement_condition (loop, bb, &cond, &gsi);
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true_bb = find_phi_replacement_condition (bb, &cond, &gsi);
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while (!gsi_end_p (phi_gsi))
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{
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@ -1765,9 +1733,6 @@ combine_blocks (struct loop *loop)
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free (ifc_bbs);
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ifc_bbs = NULL;
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/* Post-dominators are corrupt now. */
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free_dominance_info (CDI_POST_DOMINATORS);
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}
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/* If-convert LOOP when it is legal. For the moment this pass has no
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@ -1830,8 +1795,6 @@ main_tree_if_conversion (void)
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if (changed && flag_tree_loop_if_convert_stores)
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todo |= TODO_update_ssa_only_virtuals;
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free_dominance_info (CDI_POST_DOMINATORS);
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#ifdef ENABLE_CHECKING
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{
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basic_block bb;
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@ -1867,7 +1830,8 @@ const pass_data pass_data_if_conversion =
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0, /* properties_provided */
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0, /* properties_destroyed */
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0, /* todo_flags_start */
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( TODO_verify_stmts | TODO_verify_flow ), /* todo_flags_finish */
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( TODO_verify_stmts | TODO_verify_flow
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| TODO_verify_ssa ), /* todo_flags_finish */
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};
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class pass_if_conversion : public gimple_opt_pass
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