2015-03-29  Sandra Loosemore  <sandra@codesourcery.com>

	gcc/
	* common.opt (fdelete-null-pointer-checks): Init to -1.
	* config/nios2/elf.h (SUBTARGET_OVERRIDE_OPTIONS): Define to
	override flag_delete_null_pointer_checks default.
	* doc/invoke.texi (-fdelete-null-pointer-checks): Clarify
	behavior re address zero.  Better document target-specific behavior.
	(-fisolate-errneous-paths-dereference): Mention relationship to
	-fdelete-null-pointer-checks.

	gcc/testsuite/
	* lib/target-supports.exp
	(check_effective_target_keeps_null_pointer_checks): Clarify that
	this is for targets that disable -fdelete-null-pointer-checks,
	not default it to off.
	* gcc.dg/ipa/ipa-pta-14.c: Make dependence on
	-fdelete-null-pointer-checks explicit.
	* gcc.dg/tree-ssa/20030730-1.c: Likewise.
	* gcc.dg/tree-ssa/20030730-2.c: Likewise.
	* gcc.dg/tree-ssa/isolate-1.c: Likewise.
	* gcc.dg/tree-ssa/isolate-2.c: Likewise.
	* gcc.dg/tree-ssa/isolate-3.c: Likewise.
	* gcc.dg/tree-ssa/isolate-4.c: Likewise.
	* gcc.dg/tree-ssa/isolate-5.c: Likewise.
	* gcc.dg/tree-ssa/nonzero-1.c: Likewise.
	* gcc.dg/tree-ssa/pr20318.c: Likewise.
	* gcc.dg/tree-ssa/pr20701.c: Likewise.
	* gcc.dg/tree-ssa/pr20702.c: Likewise.
	* gcc.dg/tree-ssa/pr21086.c: Likewise.
	* gcc.dg/tree-ssa/pr21090.c: Likewise.
	* gcc.dg/tree-ssa/pr58480.c: Likewise.
	* gcc.dg/tree-ssa/pta-escape-1.c: Likewise.
	* gcc.dg/tree-ssa/pta-escape-2.c: Likewise.
	* gcc.dg/tree-ssa/pta-escape-3.c: Likewise.
	* gcc.dg/tree-ssa/ssa-vrp-thread-1.c: Likewise.
	* gcc.dg/tree-ssa/unreachable.c: Likewise.
	* gcc.dg/tree-ssa/vrp02.c: Likewise.
	* gcc.dg/tree-ssa/vrp07.c: Likewise.
	* gcc.dg/tree-ssa/vrp08.c: Likewise.
	* gcc.dg/tree-ssa/vrp55.c: Likewise.
	* g++.dg/cpp0x/static_assert9.C: Likewise.
	* g++.dg/tree-ssa/nonzero-1.C: Likewise.
	* g++.dg/tree-ssa/pr19476-1.C: Likewise.
	* g++.dg/tree-ssa/pr19476-2.C: Likewise.
	* g++.dg/tree-ssa/pr19476-5.C: Likewise.
	* g++.dg/tree-ssa/pr26406.C: Likewise.