PR tree-optimization/78696 - [7 Regression] -fprintf-return-value misoptimizes %.Ng where N is greater than 10

gcc/ChangeLog:

	PR tree-optimization/78696
	* gimple-ssa-sprintf.c (format_floating): Correct handling of
	precision.  Use MPFR for %f for greater fidelity.  Correct handling
	of %g.
	(pass_sprintf_length::compute_format_length): Set width and precision
	specified by asrerisk to void_node for vararg functions.
	(try_substitute_return_value): Adjust dump output.

gcc/testsuite/ChangeLog:

	PR tree-optimization/78696
	* gcc.dg/tree-ssa/builtin-sprintf-5.c: Remove incorrect test cases.
	* gcc.dg/tree-ssa/builtin-sprintf-warn-7.c: Correct off-by-1 errors.
	* gcc.dg/tree-ssa/builtin-sprintf-warn-9.c: New test.
	* gcc.dg/tree-ssa/builtin-sprintf.c: Add test cases.

From-SVN: r244037