On 02/15/2012 06:03 PM, Joseph S. Myers wrote:
> On Wed, 15 Feb 2012, Christian Bruel wrote:
>
>> Removal of this NOP_EXPR if !CAN_HAVE_LOCATION_P fixes the problem.
>> looks safe from my testing, because the loc is inserted using
>> 'protected_set_expr_location', whereas no loc for a constant case
>> doesn't seem to introduce new problems with the debugging information.
>> But in case I also added a few paranoid gcc_assert.
>
> Is it safe to set TREE_NO_WARNING without that check? I'd have thought
> the check was to avoid setting TREE_NO_WARNING on a shared node when
> warnings are to be disabled in only one context where that node is used.
>
OK, I see, we can still keep the check, like with :
Index: c-common.c
===================================================================
--- c-common.c (revision 184301)
+++ c-common.c (working copy)
@@ -1435,12 +1435,9 @@
have been done by this point, so remove them again. */
nowarning |= TREE_NO_WARNING (ret);
STRIP_TYPE_NOPS (ret);
- if (nowarning && !TREE_NO_WARNING (ret))
- {
- if (!CAN_HAVE_LOCATION_P (ret))
- ret = build1 (NOP_EXPR, TREE_TYPE (ret), ret);
- TREE_NO_WARNING (ret) = 1;
- }
+ if (nowarning && CAN_HAVE_LOCATION_P (ret))
+ TREE_NO_WARNING (ret) = 1;
+
if (ret != expr)
protected_set_expr_location (ret, loc);
return ret;
We propagate the flag to the new node for non-constant folded
expressions, or for a converted constant (so NOT_EXPR is not stripped),
Does it make sense to set TREE_NO_WARNING for a not-converted folded
constant ? it seems that in the proposal, a warning before the fold is
OK, and a warning after the fold on the new expression is still to be
honored. The NO_WARNING flag on an non-converted constant that is folded
looks unnecessary. I tried to forge different scenarios, were the result
of the folded constant would force a duplicate warning, but no success
to find a regression case.
Thanks
Christian
