| Message ID | 2618637.dVWshZqFx6@polaris |
|---|---|
| State | New |
| Headers | show |
| Series | Fix PR C++/82872 | expand |
OK. On Thu, Dec 21, 2017 at 10:51 AM, Eric Botcazou <ebotcazou@adacore.com> wrote: > Hi, > > this is an ICE in the C++ FE on an offsetof construct with __PTRDIFF_MAX__ and > it happens only with this specific index: > > In file included from pr82872.c:4: > pr82872.c: In function 'size_t foo()': > pr82872.c:10:10: internal compiler error: in ignore_overflows, at cp/cvt.c:583 > return offsetof (struct S, a[__PTRDIFF_MAX__]); > ^~~~~~~~ > 0x65ef7f ignore_overflows > /home/eric/svn/gcc/gcc/cp/cvt.c:583 > 0x661bcc ocp_convert(tree_node*, tree_node*, int, int, int) > /home/eric/svn/gcc/gcc/cp/cvt.c:817 > 0x6636e0 convert(tree_node*, tree_node*) > /home/eric/svn/gcc/gcc/cp/cvt.c:1580 > 0x882b62 fold_offsetof(tree_node*) > /home/eric/svn/gcc/gcc/c-family/c-common.c:6282 > 0x801c0c finish_offsetof(tree_node*, tree_node*, unsigned int) > /home/eric/svn/gcc/gcc/cp/semantics.c:4041 > 0x74596b cp_parser_builtin_offsetof > /home/eric/svn/gcc/gcc/cp/parser.c:9828 > > The C++ FE is quite picky about constant integer overflow during conversion > operations and checks that they can only _introduce_ overflows and never make > them disappear, the latter case occuring here in convert_to_integer_1. > > Tested on x86_64-suse-linux, OK for the mainline? > > > 2017-12-21 Eric Botcazou <ebotcazou@adacore.com> > > PR C++/82872 > * convert.c (convert_to_integer_1) <POINTER_TYPE>: Do not return > the shared zero if the input has overflowed. > > > 2017-12-21 Eric Botcazou <ebotcazou@adacore.com> > > * c-c++-common/pr82872.c: New test. > > -- > Eric Botcazou
Index: convert.c =================================================================== --- convert.c (revision 255850) +++ convert.c (working copy) @@ -671,7 +671,7 @@ convert_to_integer_1 (tree type, tree ex { case POINTER_TYPE: case REFERENCE_TYPE: - if (integer_zerop (expr)) + if (integer_zerop (expr) && !TREE_OVERFLOW (expr)) return build_int_cst (type, 0); /* Convert to an unsigned integer of the correct width first, and from
Hi, this is an ICE in the C++ FE on an offsetof construct with __PTRDIFF_MAX__ and it happens only with this specific index: In file included from pr82872.c:4: pr82872.c: In function 'size_t foo()': pr82872.c:10:10: internal compiler error: in ignore_overflows, at cp/cvt.c:583 return offsetof (struct S, a[__PTRDIFF_MAX__]); ^~~~~~~~ 0x65ef7f ignore_overflows /home/eric/svn/gcc/gcc/cp/cvt.c:583 0x661bcc ocp_convert(tree_node*, tree_node*, int, int, int) /home/eric/svn/gcc/gcc/cp/cvt.c:817 0x6636e0 convert(tree_node*, tree_node*) /home/eric/svn/gcc/gcc/cp/cvt.c:1580 0x882b62 fold_offsetof(tree_node*) /home/eric/svn/gcc/gcc/c-family/c-common.c:6282 0x801c0c finish_offsetof(tree_node*, tree_node*, unsigned int) /home/eric/svn/gcc/gcc/cp/semantics.c:4041 0x74596b cp_parser_builtin_offsetof /home/eric/svn/gcc/gcc/cp/parser.c:9828 The C++ FE is quite picky about constant integer overflow during conversion operations and checks that they can only _introduce_ overflows and never make them disappear, the latter case occuring here in convert_to_integer_1. Tested on x86_64-suse-linux, OK for the mainline? 2017-12-21 Eric Botcazou <ebotcazou@adacore.com> PR C++/82872 * convert.c (convert_to_integer_1) <POINTER_TYPE>: Do not return the shared zero if the input has overflowed. 2017-12-21 Eric Botcazou <ebotcazou@adacore.com> * c-c++-common/pr82872.c: New test.