Commit 464a1441 authored by Richard Henderson's avatar Richard Henderson
Browse files

tcg/optimize: Add more identity simplifications 



Recognize 0 operand to andc, and -1 operands to and, orc, eqv.

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 e64e958e

tcg/optimize.c

+24 −15
Original line number Diff line number Diff line
@@ -716,7 +716,7 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr, 
            break;

        }



        /* Simplify expression for "op r, a, 0 => mov r, a" cases */

        /* Simplify expression for "op r, a, const => mov r, a" cases */

        switch (op) {

        CASE_OP_32_64(add):

        CASE_OP_32_64(sub):
@@ -727,12 +727,23 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr, 
        CASE_OP_32_64(rotr):

        CASE_OP_32_64(or):

        CASE_OP_32_64(xor):

            if (temps[args[1]].state == TCG_TEMP_CONST) {

                /* Proceed with possible constant folding. */

        CASE_OP_32_64(andc):

            if (temps[args[1]].state != TCG_TEMP_CONST

                && temps[args[2]].state == TCG_TEMP_CONST

                && temps[args[2]].val == 0) {

                goto do_mov3;

            }

            break;

        CASE_OP_32_64(and):

        CASE_OP_32_64(orc):

        CASE_OP_32_64(eqv):

            if (temps[args[1]].state != TCG_TEMP_CONST

                && temps[args[2]].state == TCG_TEMP_CONST

                && temps[args[2]].val == -1) {

                goto do_mov3;

            }

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

                && temps[args[2]].val == 0) {

            break;

        do_mov3:

            if (temps_are_copies(args[0], args[1])) {

                s->gen_opc_buf[op_index] = INDEX_op_nop;

            } else {
@@ -742,8 +753,6 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr, 
            }

            args += 3;

            continue;

            }

            break;

        default:

            break;

        }