Hi!
This patch fixes a GC ICE. During debugging, I've found that during
gimplification we can actually call omp_resolve_declare_variant multiple
times and it would create a new magic declare_variant_alt FUNCTION_DECL
each time, which is undesirable, once we have such a decl, we should just
use that. The other problem is that there was no cgraph node removal hook.
As the omp_declare_variants htab is used just early during gimplification,
we can just clear the whole htab, rather than trying to lookup and remove
a particular entry. The other hash table is used later as well and that
one uses just DECL_UID as hash, so in that case the patch removes the elt.
Bootstrapped/regtested on x86_64-linux and i686-linux, committed to trunk.
2020-05-27 Jakub Jelinek <ja...@redhat.com>
PR middle-end/95315
* omp-general.c (omp_declare_variant_remove_hook): New function.
(omp_resolve_declare_variant): Always return base if it is already
declare_variant_alt magic decl itself. Register
omp_declare_variant_remove_hook as cgraph node removal hook.
* gcc.dg/gomp/pr95315.c: New test.
--- gcc/omp-general.c.jj 2020-05-26 09:35:12.222438412 +0200
+++ gcc/omp-general.c 2020-05-26 13:06:03.381443260 +0200
@@ -1695,6 +1695,28 @@ omp_resolve_late_declare_variant (tree a
return varentry2->variant->decl;
}
+/* Hook to adjust hash tables on cgraph_node removal. */
+
+static void
+omp_declare_variant_remove_hook (struct cgraph_node *node, void *)
+{
+ if (!node->declare_variant_alt)
+ return;
+
+ /* Drop this hash table completely. */
+ omp_declare_variants = NULL;
+ /* And remove node from the other hash table. */
+ if (omp_declare_variant_alt)
+ {
+ omp_declare_variant_base_entry entry;
+ entry.base = NULL;
+ entry.node = node;
+ entry.variants = NULL;
+ omp_declare_variant_alt->remove_elt_with_hash (&entry,
+ DECL_UID (node->decl));
+ }
+}
+
/* Try to resolve declare variant, return the variant decl if it should
be used instead of base, or base otherwise. */
@@ -1715,6 +1737,11 @@ omp_resolve_declare_variant (tree base)
break;
if (TREE_CODE (TREE_PURPOSE (TREE_VALUE (attr))) != FUNCTION_DECL)
continue;
+ cgraph_node *node = cgraph_node::get (base);
+ /* If this is already a magic decl created by this function,
+ don't process it again. */
+ if (node && node->declare_variant_alt)
+ return base;
switch (omp_context_selector_matches (TREE_VALUE (TREE_VALUE (attr))))
{
case 0:
@@ -1823,6 +1850,12 @@ omp_resolve_declare_variant (tree base)
}
}
+ static struct cgraph_node_hook_list *node_removal_hook_holder;
+ if (node_removal_hook_holder)
+ node_removal_hook_holder
+ = symtab->add_cgraph_removal_hook (omp_declare_variant_remove_hook,
+ NULL);
+
if (omp_declare_variants == NULL)
omp_declare_variants
= hash_table<omp_declare_variant_hasher>::create_ggc (64);
--- gcc/testsuite/gcc.dg/gomp/pr95315.c.jj 2020-05-26 13:42:42.990567525
+0200
+++ gcc/testsuite/gcc.dg/gomp/pr95315.c 2020-05-26 13:42:35.748672050 +0200
@@ -0,0 +1,5 @@
+/* PR middle-end/95315 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fopenmp --param ggc-min-heapsize=0" } */
+
+#include "../../c-c++-common/gomp/declare-variant-5.c"
Jakub
