re PR tree-optimization/31522 (False overflow warning with phi nodes)
./: PR tree-optimization/31522 * tree-vrp.c (vr_phi_edge_counts): New static variable. (vrp_initialize): Allocate vr_phi_edge_counts. (vrp_visit_phi_node): Don't push to infinity if we saw a new executable edge. Drop test for all constants. (vrp_finalize): Free vrp_phi_edge_counts. testsuite/: PR tree-optimization/31522 * gcc.dg/Wstrict-overflow-16.c: New test. From-SVN: r123908
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@ -1,5 +1,12 @@
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2007-04-16 Ian Lance Taylor <iant@google.com>
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PR tree-optimization/31522
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* tree-vrp.c (vr_phi_edge_counts): New static variable.
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(vrp_initialize): Allocate vr_phi_edge_counts.
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(vrp_visit_phi_node): Don't push to infinity if we saw a new
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executable edge. Drop test for all constants.
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(vrp_finalize): Free vrp_phi_edge_counts.
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* doc/cpp.texi (Common Predefined Macros): Clarify description of
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__GNUC_GNU_INLINE__ and __GNUC_STDC_INLINE__.
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@ -1,3 +1,8 @@
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2007-04-16 Ian Lance Taylor <iant@google.com>
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PR tree-optimization/31522
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* gcc.dg/Wstrict-overflow-16.c: New test.
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2007-04-17 Kazu Hirata <kazu@codesourcery.com>
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* gcc.dg/cpp/_Pragma6.c: Skip on fido-*-* and m68k-*-*.
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@ -0,0 +1,11 @@
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/* { dg-do compile } */
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/* { dg-options "-fstrict-overflow -O2 -Wstrict-overflow" } */
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/* From PR 31522. */
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int f (int x) {
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int y;
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if (x <= 4) y = 1;
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else y = x / 4;
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return y <= 0;
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}
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@ -95,6 +95,11 @@ static sbitmap blocks_visited;
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of values that SSA name N_I may take. */
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static value_range_t **vr_value;
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/* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
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number of executable edges we saw the last time we visited the
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node. */
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static int *vr_phi_edge_counts;
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/* Return whether TYPE should use an overflow infinity distinct from
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TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
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@ -4433,6 +4438,7 @@ vrp_initialize (void)
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basic_block bb;
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vr_value = XCNEWVEC (value_range_t *, num_ssa_names);
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vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
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FOR_EACH_BB (bb)
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{
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@ -5185,7 +5191,7 @@ vrp_visit_phi_node (tree phi)
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tree lhs = PHI_RESULT (phi);
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value_range_t *lhs_vr = get_value_range (lhs);
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value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
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bool all_const = true;
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int edges, old_edges;
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copy_value_range (&vr_result, lhs_vr);
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@ -5195,6 +5201,7 @@ vrp_visit_phi_node (tree phi)
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print_generic_expr (dump_file, phi, dump_flags);
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}
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edges = 0;
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for (i = 0; i < PHI_NUM_ARGS (phi); i++)
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{
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edge e = PHI_ARG_EDGE (phi, i);
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@ -5212,10 +5219,11 @@ vrp_visit_phi_node (tree phi)
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tree arg = PHI_ARG_DEF (phi, i);
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value_range_t vr_arg;
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++edges;
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if (TREE_CODE (arg) == SSA_NAME)
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{
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vr_arg = *(get_value_range (arg));
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all_const = false;
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}
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else
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{
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@ -5244,11 +5252,16 @@ vrp_visit_phi_node (tree phi)
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if (vr_result.type == VR_VARYING)
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goto varying;
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old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
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vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
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/* To prevent infinite iterations in the algorithm, derive ranges
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when the new value is slightly bigger or smaller than the
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previous one. */
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previous one. We don't do this if we have seen a new executable
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edge; this helps us avoid an overflow infinity for conditionals
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which are not in a loop. */
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if (lhs_vr->type == VR_RANGE && vr_result.type == VR_RANGE
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&& !all_const)
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&& edges <= old_edges)
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{
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if (!POINTER_TYPE_P (TREE_TYPE (lhs)))
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{
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@ -5827,10 +5840,12 @@ vrp_finalize (void)
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free (single_val_range);
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free (vr_value);
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free (vr_phi_edge_counts);
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/* So that we can distinguish between VRP data being available
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and not available. */
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vr_value = NULL;
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vr_phi_edge_counts = NULL;
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}
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