* gcc.c (sanitize_spec_function): Handle SANITIZE_FLOAT_DIVIDE.
	* builtins.def: Initialize builtins even for SANITIZE_FLOAT_DIVIDE.
	* flag-types.h (enum sanitize_code): Add SANITIZE_FLOAT_DIVIDE.
	* opts.c (common_handle_option): Add -fsanitize=float-divide-by-zero.
c-family/
	* c-ubsan.c (ubsan_instrument_division): Handle REAL_TYPEs.  Perform
	INT_MIN / -1 sanitization only for integer types.
c/
	* c-typeck.c (build_binary_op): Call ubsan_instrument_division
	also when SANITIZE_FLOAT_DIVIDE is on.
cp/
	* typeck.c (cp_build_binary_op): Call ubsan_instrument_division
	even when SANITIZE_FLOAT_DIVIDE is on.  Set doing_div_or_mod even
	for non-integer types.
testsuite/
	* c-c++-common/ubsan/div-by-zero-5.c: Fix formatting.
	* c-c++-common/ubsan/float-div-by-zero-1.c: New test.

From-SVN: r209927