analyzer: warn on the use of floating-points operands in the size argument [PR106181]

analyzer: warn on the use of floating-points operands in the size argument [PR106181]

This patch fixes the ICE reported in PR106181 and adds a new warning to
the analyzer complaining about the use of floating-point operands.

Regrtested on Linux x86_64.

2022-08-17  Tim Lange  <mail@tim-lange.me>

gcc/analyzer/ChangeLog:

	PR analyzer/106181
	* analyzer.opt: Add Wanalyzer-imprecise-floating-point-arithmetic.
	* region-model.cc (is_any_cast_p): Formatting.
	(region_model::check_region_size): Ensure precondition.
	(class imprecise_floating_point_arithmetic): New abstract
	diagnostic class for all floating-point related warnings.
	(class float_as_size_arg): Concrete diagnostic class to complain
	about floating-point operands inside the size argument.
	(class contains_floating_point_visitor):
	New visitor to find floating-point operands inside svalues.
	(region_model::check_dynamic_size_for_floats): New function.
	(region_model::set_dynamic_extents):
	Call to check_dynamic_size_for_floats.
	* region-model.h (class region_model):
	Add region_model::check_dynamic_size_for_floats.

gcc/ChangeLog:

	PR analyzer/106181
	* doc/invoke.texi: Add Wanalyzer-imprecise-fp-arithmetic.

gcc/testsuite/ChangeLog:

	PR analyzer/106181
	* gcc.dg/analyzer/allocation-size-1.c: New test.
	* gcc.dg/analyzer/imprecise-floating-point-1.c: New test.
	* gcc.dg/analyzer/pr106181.c: New test.