ifcombine: For short circuit case, allow 2 convert defining statements [PR85605]

ifcombine: For short circuit case, allow 2 convert defining statements [PR85605]

r0-126134-g5d2a9da9a7f7c1 added support for circuiting and combing the ifs
into using either AND or OR. But it only allowed the inner condition
basic block having the conditional only. This changes to allow up to 2 defining
statements as long as they are just integer to integer conversions for
either the lhs or rhs of the conditional.

This should allow to use ccmp on aarch64 and x86_64 (APX) slightly more than before.

Boootstrapped and tested on x86_64-linux-gnu.

	PR tree-optimization/85605

gcc/ChangeLog:

	* tree-ssa-ifcombine.cc (can_combine_bbs_with_short_circuit): New function.
	(ifcombine_ifandif): Use can_combine_bbs_with_short_circuit
	instead of checking if iterator is one before the last statement.

gcc/testsuite/ChangeLog:

	* g++.dg/tree-ssa/ifcombine-ccmp-1.C: New test.
	* gcc.dg/tree-ssa/ssa-ifcombine-ccmp-7.c: New test.
	* gcc.dg/tree-ssa/ssa-ifcombine-ccmp-8.c: New test.
	* gcc.dg/tree-ssa/ssa-ifcombine-ccmp-9.c: New test.

Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>