On 01/01/2018 03:30 PM, Martin Sebor wrote: > PR tree-optimization/83640 - ice in generic_overlap at > gimple-ssa-warn-restrict.c:814 highlights out a class of cases > where the -Wrestrict checker assumes that the range of a pointer > offset that us represented by a VR_RANGE has a lower bound that > is less than its upper bound. The pass asserts that this is so > and cases to the contrary trigger an ICE. > > The submitted test case that triggers this ICE is due to a missed > optimization in tree-ssa-strlen (which could, and IMO should, > guarantee that the offsets it constructs are in such a range, and > I'll submit a separate patch with that change), but the assumption > isn't safe in general for offsets whose range happens to straddle > the PTRDIFF_MAX boundary, i.e., whose lower bound is greater than > its upper bound. > > The attached patch makes adjustments to remove this assumption > and avoid the ICE. Tested on x86_64-linux with no regressions. > > Martin > > PS The patch also removes the same troublesome assertion that's > also removed in the one below: > > https://gcc.gnu.org/ml/gcc-patches/2017-12/msg01399.html > > gcc-83640.diff > > > PR tree-optimization/83640 - ice in generic_overlap at > gimple-ssa-warn-restrict.c:814 > > gcc/ChangeLog: > > PR tree-optimization/83640 > * gimple-ssa-warn-restrict.c (builtin_access::builtin_access): Avoid > subtracting negative offset from size. > (builtin_access::overlap): Adjust offset bounds of the access to fall > within the size of the object if possible. > (maybe_diag_overlap): Remove troublesome assertion. > > gcc/testsuite/ChangeLog: > > PR tree-optimization/83640 > * gcc.dg/Wrestrict-3.c: New test. > * gcc.dg/pr83640.c: New test. I fixed the trivial conflict with the assertion removal and renamed the test from Wrestrict-3.c to Wrestrict-5.c due to a conflict.
Installed onto the trunk. Thanks, jeff
