Allow libcalls for complex memcpy when optimizing for size.

Allow libcalls for complex memcpy when optimizing for size.

The RISC-V backend wants to use a libcall when optimizing for size if
more than 6 instructions are needed.  Emit_move_complex asks for no
libcalls.  This case requires 8 insns for rv64 and 16 insns for rv32,
so we get fallback code that emits a loop.  Commit_one_edge_insertion
doesn't allow code inserted for a phi node on an edge to end with a
branch, and so this triggers an assertion.  This problem goes away if
we allow libcalls when optimizing for size, which gives the code the
RISC-V backend wants, and avoids triggering the assert.

	gcc/
	PR middle-end/92263
	* expr.c (emit_move_complex): Only use BLOCK_OP_NO_LIBCALL when
	optimize_insn_for_speed_p is true.

	gcc/testsuite/
	PR middle-end/92263
	* gcc.dg/pr92263.c: New.

From-SVN: r277861