diff options
| -rw-r--r-- | tcg/tcg.c | 12 | ||||
| -rw-r--r-- | tcg/tcg.h | 4 |
2 files changed, 12 insertions, 4 deletions
@@ -1122,9 +1122,11 @@ static void tcg_liveness_analysis(TCGContext *s) dead_temps[arg] = 1; } - /* globals are live (they may be used by the call) */ - memset(dead_temps, 0, s->nb_globals); - + if (!(call_flags & TCG_CALL_CONST)) { + /* globals are live (they may be used by the call) */ + memset(dead_temps, 0, s->nb_globals); + } + /* input args are live */ dead_iargs = 0; for(i = 0; i < nb_iargs; i++) { @@ -1821,7 +1823,9 @@ static int tcg_reg_alloc_call(TCGContext *s, const TCGOpDef *def, /* store globals and free associated registers (we assume the call can modify any global. */ - save_globals(s, allocated_regs); + if (!(flags & TCG_CALL_CONST)) { + save_globals(s, allocated_regs); + } tcg_out_op(s, opc, &func_arg, &const_func_arg); @@ -178,6 +178,10 @@ typedef int TCGv_i64; and cannot raise exceptions. Hence a call to a pure function can be safely suppressed if the return value is not used. */ #define TCG_CALL_PURE 0x0010 +/* A const function only reads its arguments and does not use TCG + globals variables. Hence a call to such a function does not + save TCG globals variabes back to their canonical location. */ +#define TCG_CALL_CONST 0x0020 /* used to align parameters */ #define TCG_CALL_DUMMY_TCGV MAKE_TCGV_I32(-1) |