Commit 8cf9a3d3 authored by Richard Henderson's avatar Richard Henderson
Browse files

tcg/aarch64: Fix tcg_out_movi 



There were some patterns, like 0x0000_ffff_ffff_00ff, for which we
would select to begin a multi-insn sequence with MOVN, but would
fail to set the 0x0000 lane back from 0xffff.

Signed-off-by: default avatarRichard Henderson <rth@twiddle.net>
Message-Id: <20161207180727.6286-3-rth@twiddle.net>
parent b1eb20da

tcg/aarch64/tcg-target.inc.c

+24 −33
Original line number Diff line number Diff line
@@ -580,11 +580,9 @@ static void tcg_out_logicali(TCGContext *s, AArch64Insn insn, TCGType ext, 
static void tcg_out_movi(TCGContext *s, TCGType type, TCGReg rd,

                         tcg_target_long value)

{

    AArch64Insn insn;

    int i, wantinv, shift;

    tcg_target_long svalue = value;

    tcg_target_long ivalue = ~value;

    tcg_target_long imask;



    /* For 32-bit values, discard potential garbage in value.  For 64-bit

       values within [2**31, 2**32-1], we can create smaller sequences by
@@ -630,43 +628,36 @@ static void tcg_out_movi(TCGContext *s, TCGType type, TCGReg rd, 


    /* Would it take fewer insns to begin with MOVN?  For the value and its

       inverse, count the number of 16-bit lanes that are 0.  */

    for (i = wantinv = imask = 0; i < 64; i += 16) {

    for (i = wantinv = 0; i < 64; i += 16) {

        tcg_target_long mask = 0xffffull << i;

        if ((value & mask) == 0) {

            wantinv -= 1;

        }

        if ((ivalue & mask) == 0) {

            wantinv += 1;

            imask |= mask;

        }

    }



    /* If we had more 0xffff than 0x0000, invert VALUE and use MOVN.  */

    insn = I3405_MOVZ;

    if (wantinv > 0) {

        value = ivalue;

        insn = I3405_MOVN;

        wantinv -= ((value & mask) == 0);

        wantinv += ((ivalue & mask) == 0);

    }



    if (wantinv <= 0) {

        /* Find the lowest lane that is not 0x0000.  */

        shift = ctz64(value) & (63 & -16);

    tcg_out_insn_3405(s, insn, type, rd, value >> shift, shift);



    if (wantinv > 0) {

        /* Re-invert the value, so MOVK sees non-inverted bits.  */

        value = ~value;

        /* Clear out all the 0xffff lanes.  */

        value ^= imask;

    }

        tcg_out_insn(s, 3405, MOVZ, type, rd, value >> shift, shift);

        /* Clear out the lane that we just set.  */

        value &= ~(0xffffUL << shift);



    /* Iterate until all lanes have been set, and thus cleared from VALUE.  */

        /* Iterate until all non-zero lanes have been processed.  */

        while (value) {

            shift = ctz64(value) & (63 & -16);

            tcg_out_insn(s, 3405, MOVK, type, rd, value >> shift, shift);

            value &= ~(0xffffUL << shift);

        }

    } else {

        /* Like above, but with the inverted value and MOVN to start.  */

        shift = ctz64(ivalue) & (63 & -16);

        tcg_out_insn(s, 3405, MOVN, type, rd, ivalue >> shift, shift);

        ivalue &= ~(0xffffUL << shift);

        while (ivalue) {

            shift = ctz64(ivalue) & (63 & -16);

            /* Provide MOVK with the non-inverted value.  */

            tcg_out_insn(s, 3405, MOVK, type, rd, ~(ivalue >> shift), shift);

            ivalue &= ~(0xffffUL << shift);

        }

    }

}



/* Define something more legible for general use.  */