match.pd: Avoid (intptr_t)x eq/ne CST to x eq/ne (typeof x) CST opt in GENERIC when...

match.pd: Avoid (intptr_t)x eq/ne CST to x eq/ne (typeof x) CST opt in GENERIC when sanitizing [PR101210]

When we have (intptr_t) x == cst where x has REFERENCE_TYPE, this
optimization creates x == cst out of it where cst has REFERENCE_TYPE.
If it is done in GENERIC folding, it can results in ubsan failures
where the INTEGER_CST with REFERENCE_TYPE is instrumented.

Fixed by deferring it to GIMPLE folding in this case.

2021-06-29  Jakub Jelinek  <jakub@redhat.com>

	PR c++/101210
	* match.pd ((intptr_t)x eq/ne CST to x eq/ne (typeof x) CST): Don't
	perform the optimization in GENERIC when sanitizing and x has a
	reference type.

	* g++.dg/ubsan/pr101210.C: New test.

(cherry picked from commit 53fd7544aff6d0a18869017cb9bb921a7f5dcd04)