re PR tree-optimization/83640 (ICE in generic_overlap, at gimple-ssa-warn-restrict...

re PR tree-optimization/83640 (ICE in generic_overlap, at gimple-ssa-warn-restrict.c:814)

2018-01-06  Martin Sebor  <msebor@redhat.com>

	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.

	PR tree-optimization/83640
	* gcc.dg/Wrestrict-6.c: New test.
	* gcc.dg/pr83640.c: New test.

From-SVN: r256319