Hi,
this patch fixes ICE in lto.c caused by the (ab)use of TREE_CHAIN
by lto_symtab_prevail_decl. We check twice that TREE_CHAIN does not
point to a decl - once before merging and once after. It is sufficient
to do it once. I also noticed that LTO_NO_PREVAIL use gcc_assert
and replaced it by gcc_checking_assert so lto_fixup_prevailing_decls
gets faster. It shows in the profiles.
Bootstrapped/regtsted x86_64-linux and Markus tested it fixes the
Firefox for him. Comitted.
Honza
Index: ChangeLog
===================================================================
--- ChangeLog (revision 231473)
+++ ChangeLog (working copy)
@@ -1,6 +1,13 @@
2015-12-08 Jan Hubicka <hubi...@ucw.cz>
PR lto/68811
+ * lto.c (lto_fixup_prevailing_decls): Do not check TREE_CHAIN of
+ DECL.
+ (LTO_NO_PREVAIL): Use gcc_checking_assert.
+
+2015-12-08 Jan Hubicka <hubi...@ucw.cz>
+
+ PR lto/68811
* lto-symtab.c (lto_symtab_merge_decls_2): Decl can never be prevailed
by itself.
Index: lto.c
===================================================================
--- lto.c (revision 231472)
+++ lto.c (working copy)
@@ -2517,7 +2517,7 @@ lto_wpa_write_files (void)
/* Ensure that TT isn't a replacable var of function decl. */
#define LTO_NO_PREVAIL(tt) \
- gcc_assert (!(tt) || !VAR_OR_FUNCTION_DECL_P (tt))
+ gcc_checking_assert (!(tt) || !VAR_OR_FUNCTION_DECL_P (tt))
/* Given a tree T replace all fields referring to variables or functions
with their prevailing variant. */
@@ -2529,7 +2529,10 @@ lto_fixup_prevailing_decls (tree t)
gcc_checking_assert (code != TREE_BINFO);
LTO_NO_PREVAIL (TREE_TYPE (t));
- if (CODE_CONTAINS_STRUCT (code, TS_COMMON))
+ if (CODE_CONTAINS_STRUCT (code, TS_COMMON)
+ /* lto_symtab_prevail_decl use TREE_CHAIN to link to the prevailing decl.
+ in the case T is a prevailed declaration we would ICE here. */
+ && !VAR_OR_FUNCTION_DECL_P (t))
LTO_NO_PREVAIL (TREE_CHAIN (t));
if (DECL_P (t))
{
