lower-bitint: Don't use m_loads for loads used in GIMPLE_ASM [PR113464]

lower-bitint: Don't use m_loads for loads used in GIMPLE_ASM [PR113464]

Like for GIMPLE_PHIs or calls, even for GIMPLE_ASMs we want
a corresponding VAR_DECL assigned for lhs SSA_NAMEs of loads
from memory, as even GIMPLE_ASM relies on those VAR_DECLs to exist.

2024-01-19  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/113464
	* gimple-lower-bitint.cc (gimple_lower_bitint): Don't try to
	optimize loads into GIMPLE_ASM stmts.

	* gcc.dg/bitint-75.c: New test.