http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50448
Georg-Johann Lay <gjl at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |bonzini at gnu dot org
--- Comment #3 from Georg-Johann Lay <gjl at gcc dot gnu.org> 2011-10-28
12:59:28 UTC ---
The issue is still present for avr (4.7 trunk r180399).
There is a patch proposed by Paolo that fixes the issue:
Can someone of you integrate that patch? I have no access to compile farm and
cannot test for all languages/targets/hosts that might be affected.
Index: cprop.c
===================================================================
--- cprop.c (revision 177688)
+++ cprop.c (working copy)
@@ -764,6 +764,18 @@ try_replace_reg (rtx from, rtx to, rtx i
note = set_unique_reg_note (insn, REG_EQUAL, copy_rtx (src));
}
+ if (set && MEM_P (SET_DEST (set)) && reg_mentioned_p (from, SET_DEST (set)))
+ {
+ /* If above failed and this is a single set, try to simplify the source
of
+ the set given our substitution. We could perhaps try this for multiple
+ SETs, but it probably won't buy us anything. */
+ rtx addr = simplify_replace_rtx (SET_DEST (set), from, to);
+
+ if (!rtx_equal_p (addr, SET_DEST (set))
+ && validate_change (insn, &SET_DEST (set), addr, 0))
+ success = 1;
+ }
+
/* REG_EQUAL may get simplified into register.
We don't allow that. Remove that note. This code ought
not to happen, because previous code ought to synthesize
