| Message ID | 4F7079C8.1070900@codesourcery.com |
|---|---|
| State | New |
| Headers | show |
On 03/26/2012 09:14 AM, Meador Inge wrote: > Hi All, > > This patch fixes an ICE that occurs when attempting to fold nested INDIRECT_REF > trees that have conversions in between the indirect references. For example: > > constexpr unsigned long b = *((ul_ptr)(*((ul_ptr)0x0))); > > What happens is that 'cxx_fold_indirect_ref' gets the top indirect reference, > strips out all the conversions ending up with the nested indirect reference, > and then asserts that the type is a pointer type, which (obviously) it isn't. > > This patch fixes the problem by exiting the fold for non-pointer sub-trees > instead of doing the assert. 'fold_indirect_ref_1' already does things this > way. > > Tested on x86_64 GNU/Linux. OK? > > Also, This fixes the problem on trunk, but I have reproduced the issue back to > the 4.6 branch as well. On the 4.6 branch I think it is OK to just remove the > 'gcc_assert (POINTER_TYPE_P (subtype))' assert. I tested this and saw no > regressions. > > P.S. If it is OK can some please commit for me? I don't have write access. Hi Jason, I saw where the fix for this got committed in r185890. Thanks for applying it for me. What about the release branches? I can reproduce the ICE in 4.6 and 4.7. The patch from trunk applies to 4.7. For 4.6 I think we can just drop the assert.
Index: gcc/testsuite/g++.dg/cpp0x/constexpr-52672.C =================================================================== --- gcc/testsuite/g++.dg/cpp0x/constexpr-52672.C (revision 0) +++ gcc/testsuite/g++.dg/cpp0x/constexpr-52672.C (revision 0) @@ -0,0 +1,8 @@ +// PR c++/52672 +// { dg-do compile } +// { dg-options "-std=c++11" } + +typedef unsigned long * ul_ptr; +constexpr unsigned long a = *((ul_ptr)0x0); // { dg-error "" } +constexpr unsigned long b = *((ul_ptr)(*((ul_ptr)0x0))); // { dg-error "" } +constexpr unsigned long c = *((ul_ptr)*((ul_ptr)(*((ul_ptr)0x0)))); // { dg-error "" } Index: gcc/cp/semantics.c =================================================================== --- gcc/cp/semantics.c (revision 185750) +++ gcc/cp/semantics.c (working copy) @@ -7202,7 +7202,8 @@ cxx_fold_indirect_ref (location_t loc, tree type, sub = op0; STRIP_NOPS (sub); subtype = TREE_TYPE (sub); - gcc_assert (POINTER_TYPE_P (subtype)); + if (!POINTER_TYPE_P (subtype)) + return NULL_TREE; if (TREE_CODE (sub) == ADDR_EXPR) {