ipa: Check cst type when propagating controled uses info

ipa: Check cst type when propagating controled uses info

PR 105639 shows that code with type-mismatches can trigger an assert
after runnning into a branch that was inteded only for references to
variables - as opposed to references to functions.  Fixed by moving
the condition from the assert to the guarding if statement.

gcc/ChangeLog:

2022-05-25  Martin Jambor  <mjambor@suse.cz>

	PR ipa/105639
	* ipa-prop.cc (propagate_controlled_uses): Check type of the
	constant before adding a LOAD reference.

gcc/testsuite/ChangeLog:

2022-05-25  Martin Jambor  <mjambor@suse.cz>

	PR ipa/105639
	* gcc.dg/ipa/pr105639.c: New test.

(cherry picked from commit f571596f8cd8fbad34305b4bec1a813620e0cbf0)