I'm soliciting feedback regrading a problem in the 4.0.2 release.
PR 23993 is a rejects-valid C++ PR that represents a regression from
GCC 4.0.1. That's particularly unfortunate; we really want to avoid
introducing new breakage on the release branch.
It is, sadly, more fallout from my static data member patch; it has
uncovered a latent bug in integral_constant_value.
Here is the test case from the PR:
const int data[2][4] = {
{ 0, 1, 2, 3 }
};
template <typename T>
void t(int k) {
int candidate = data[1][k];
}
The key is that an const array (or, perhaps, structure) of integral
type is accessed in a template. I have a patch for the PR, which I am
testing now; the patch is attached, and is relatively simple.
So, my options are:
1. Release 4.0.2 without fixing this PR. (The bits are ready, sitting
on my disk.)
2. Apply the patch, respin the release, and release it.
3. Apply the patch, spin RC3, and go through another testing cycle.
My current plan is (2) because I think that this is an important bug
and because I think the patch is safe and, in particular, highly
unlikely to introduce any follow-on problems of its own. However, I
realize that I can't be entirely objective about this situation, so
I'd appreciate any feedback.
--
Mark Mitchell
CodeSourcery, LLC
[EMAIL PROTECTED]
Index: init.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cp/init.c,v
retrieving revision 1.429
diff -c -5 -p -r1.429 init.c
*** init.c 6 Sep 2005 14:55:03 -0000 1.429
--- init.c 21 Sep 2005 13:26:27 -0000
*************** build_offset_ref (tree type, tree name,
*** 1565,1580 ****
[5.19/1]. FIXME:If we did lazy folding, this could be localized. */
tree
integral_constant_value (tree decl)
{
! while ((TREE_CODE (decl) == CONST_DECL
! || (TREE_CODE (decl) == VAR_DECL
! /* And so are variables with a 'const' type -- unless they
! are also 'volatile'. */
! && CP_TYPE_CONST_NON_VOLATILE_P (TREE_TYPE (decl))
! && DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (decl))))
{
tree init;
/* If DECL is a static data member in a template class, we must
instantiate it here. The initializer for the static data
member is not processed until needed; we need it now. */
--- 1565,1576 ----
[5.19/1]. FIXME:If we did lazy folding, this could be localized. */
tree
integral_constant_value (tree decl)
{
! while (TREE_CODE (decl) == CONST_DECL
! || DECL_INTEGRAL_CONSTANT_VAR_P (decl))
{
tree init;
/* If DECL is a static data member in a template class, we must
instantiate it here. The initializer for the static data
member is not processed until needed; we need it now. */
