Commit 23ec69ed authored by Richard Henderson's avatar Richard Henderson
Browse files

tcg/optimize: Handle known-zeros masks for ANDC 



Reviewed-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: default avatarAurelien Jarno <aurelien@aurel32.net>
Signed-off-by: default avatarRichard Henderson <rth@twiddle.net>
parent c8d70272

tcg/optimize.c

+11 −0
Original line number Diff line number Diff line
@@ -727,6 +727,17 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr, 
            mask = temps[args[1]].mask & mask;

            break;



        CASE_OP_32_64(andc):

            /* Known-zeros does not imply known-ones.  Therefore unless

               args[2] is constant, we can't infer anything from it.  */

            if (temps[args[2]].state == TCG_TEMP_CONST) {

                mask = ~temps[args[2]].mask;

                goto and_const;

            }

            /* But we certainly know nothing outside args[1] may be set. */

            mask = temps[args[1]].mask;

            break;



        case INDEX_op_sar_i32:

            if (temps[args[2]].state == TCG_TEMP_CONST) {

                mask = (int32_t)temps[args[1]].mask >> temps[args[2]].val;