On Tue, Feb 15, 2011 at 01:44:50PM +0000, Peter Maydell wrote:
> For Neon shifts by immediate and narrow, correctly handle the case
> where the source registers and the destination registers overlap
> (the second pass should use the original register contents, not the
> results of the first pass).
>
> Signed-off-by: Peter Maydell <[email protected]>
> ---
> target-arm/translate.c | 38 +++++++++++++++++++++++++++-----------
> 1 files changed, 27 insertions(+), 11 deletions(-)
That looks correct, but it makes GCC (tested 4.3 to 4.6) complaining:
| cc1: warnings being treated as errors
| qemu/target-arm/translate.c: In function ‘disas_neon_data_insn’:
| qemu/target-arm/translate.c:4185: error: ‘tmp4’ may be used uninitialized in
this function
| qemu/target-arm/translate.c:4185: error: ‘tmp5’ may be used uninitialized in
this function
For a quick look, it seems to be a GCC issue, but we have no other
choices than workarouding it.
> diff --git a/target-arm/translate.c b/target-arm/translate.c
> index a02b20f..4d5d305 100644
> --- a/target-arm/translate.c
> +++ b/target-arm/translate.c
> @@ -4839,31 +4839,47 @@ static int disas_neon_data_insn(CPUState * env,
> DisasContext *s, uint32_t insn)
> abort();
> }
>
> + if (size == 3) {
> + neon_load_reg64(cpu_V0, rm);
> + neon_load_reg64(cpu_V1, rm + 1);
> + } else {
> + tmp4 = neon_load_reg(rm + 1, 0);
> + tmp5 = neon_load_reg(rm + 1, 1);
> + }
> for (pass = 0; pass < 2; pass++) {
> if (size == 3) {
> - neon_load_reg64(cpu_V0, rm + pass);
> + TCGv_i64 in;
> + if (pass == 0) {
> + in = cpu_V0;
> + } else {
> + in = cpu_V1;
> + }
> if (q) {
> if (input_unsigned) {
> - gen_helper_neon_rshl_u64(cpu_V0, cpu_V0,
> - tmp64);
> + gen_helper_neon_rshl_u64(cpu_V0, in, tmp64);
> } else {
> - gen_helper_neon_rshl_s64(cpu_V0, cpu_V0,
> - tmp64);
> + gen_helper_neon_rshl_s64(cpu_V0, in, tmp64);
> }
> } else {
> if (input_unsigned) {
> - gen_helper_neon_shl_u64(cpu_V0, cpu_V0,
> - tmp64);
> + gen_helper_neon_shl_u64(cpu_V0, in, tmp64);
> } else {
> - gen_helper_neon_shl_s64(cpu_V0, cpu_V0,
> - tmp64);
> + gen_helper_neon_shl_s64(cpu_V0, in, tmp64);
> }
> }
> } else {
> - tmp = neon_load_reg(rm + pass, 0);
> + if (pass == 0) {
> + tmp = neon_load_reg(rm, 0);
> + } else {
> + tmp = tmp4;
> + }
> gen_neon_shift_narrow(size, tmp, tmp2, q,
> input_unsigned);
> - tmp3 = neon_load_reg(rm + pass, 1);
> + if (pass == 0) {
> + tmp3 = neon_load_reg(rm, 1);
> + } else {
> + tmp3 = tmp5;
> + }
> gen_neon_shift_narrow(size, tmp3, tmp2, q,
> input_unsigned);
> tcg_gen_concat_i32_i64(cpu_V0, tmp, tmp3);
> --
> 1.7.1
>
>
>
--
Aurelien Jarno GPG: 1024D/F1BCDB73
[email protected] http://www.aurel32.net
