The number of registers needed for the return value of TCG opcode INDEX_op_call is calculated in function tcg_gen_callN (nb_rets).
It can be 0 or 1, for 32 bit hosts also 2 (return 64 bit value in two 32 bit registers). Some TCG implementations reserve 2 registers although only 1 is used. The following patches fix this. [PATCH 1/5] tcg/i386: Only one call output register needed for 64 bit hosts [PATCH 2/5] tcg/ia64: Only one call output register needed for 64 bit hosts [PATCH 3/5] tcg/s390: Only one call output register needed for 64 bit hosts [PATCH 4/5] tcg/sparc: Only one call output register needed for 64 bit hosts [PATCH 5/5] tcg/ppc64: Only one call output register needed for 64 bit hosts
