> -----Original Message-----
> From: Marco Liebel (QUIC) <quic_mlie...@quicinc.com>
> Sent: Monday, May 22, 2023 12:47 PM
> To: qemu-devel@nongnu.org
> Cc: Taylor Simpson <tsimp...@quicinc.com>; Brian Cain <bc...@quicinc.com>;
> Marco Liebel (QUIC) <quic_mlie...@quicinc.com>
> Subject: [PATCH v2] Hexagon (target/hexagon) Fix assignment to tmp registers
>
> The order in which instructions are generated by gen_insn() influences
> assignment to tmp registers. During generation, tmp instructions (e.g.
> generate_V6_vassign_tmp) use vreg_src_off() to determine what kind of
> register to use as source. If some instruction (e.g.
> generate_V6_vmpyowh_64_acc) uses a tmp register but is generated prior
> to the corresponding tmp instruction, the vregs_updated_tmp bit map
> isn't updated in time.
>
> Exmple:
> { v14.tmp = v16; v25 = v14 } This works properly because
> generate_V6_vassign_tmp is generated before generate_V6_vassign
> and the bit map is updated.
>
> { v15:14.tmp = vcombine(v21, v16); v25:24 += vmpyo(v18.w,v14.h) }
> This does not work properly because vmpyo is generated before
> vcombine and therefore the bit map does not yet know that there's
> a tmp register.
>
> The parentheses in the decoding function were in the wrong place.
> Moving them to the correct location makes shuffling of .tmp vector
> registers work as expected.
>
> Signed-off-by: Marco Liebel <quic_mlie...@quicinc.com>
> ---
> target/hexagon/mmvec/decode_ext_mmvec.c | 8 +++----
> tests/tcg/hexagon/hvx_misc.c | 31 +++++++++++++++++++++++++
> 2 files changed, 35 insertions(+), 4 deletions(-)
>
> diff --git a/target/hexagon/mmvec/decode_ext_mmvec.c
> b/target/hexagon/mmvec/decode_ext_mmvec.c
> index 061a65ab88..174eb3b78b 100644
> --- a/target/hexagon/mmvec/decode_ext_mmvec.c
> +++ b/target/hexagon/mmvec/decode_ext_mmvec.c
> @@ -1,5 +1,5 @@
> /*
> - * Copyright(c) 2019-2021 Qualcomm Innovation Center, Inc. All Rights
> Reserved.
> + * Copyright(c) 2019-2023 Qualcomm Innovation Center, Inc. All Rights
> Reserved.
> *
> * This program is free software; you can redistribute it and/or modify
> * it under the terms of the GNU General Public License as published by
> @@ -148,9 +148,9 @@ decode_shuffle_for_execution_vops(Packet *pkt)
> int i;
> for (i = 0; i < pkt->num_insns; i++) {
> uint16_t opcode = pkt->insn[i].opcode;
> - if (GET_ATTRIB(opcode, A_LOAD) &&
> - (GET_ATTRIB(opcode, A_CVI_NEW) ||
> - GET_ATTRIB(opcode, A_CVI_TMP))) {
> + if ((GET_ATTRIB(opcode, A_LOAD) &&
> + GET_ATTRIB(opcode, A_CVI_NEW)) ||
> + GET_ATTRIB(opcode, A_CVI_TMP)) {
> /*
> * Find prior consuming vector instructions
> * Move to end of packet
> diff --git a/tests/tcg/hexagon/hvx_misc.c b/tests/tcg/hexagon/hvx_misc.c
> index 09dec8d7a1..b45170acd1 100644
> --- a/tests/tcg/hexagon/hvx_misc.c
> +++ b/tests/tcg/hexagon/hvx_misc.c
> @@ -60,6 +60,36 @@ static void test_load_tmp(void)
> check_output_w(__LINE__, BUFSIZE);
> }
>
> +static void test_load_tmp2(void)
> +{
> + void *pout0 = &output[0];
> + void *pout1 = &output[1];
> +
> + asm volatile(
> + "r0 = #0x03030303\n\t"
> + "v16 = vsplat(r0)\n\t"
> + "r0 = #0x04040404\n\t"
> + "v18 = vsplat(r0)\n\t"
> + "r0 = #0x05050505\n\t"
> + "v21 = vsplat(r0)\n\t"
> + "{\n\t"
> + " v25:24 += vmpyo(v18.w, v14.h)\n\t"
> + " v15:14.tmp = vcombine(v21, v16)\n\t"
> + "}\n\t"
> + "vmem(%0 + #0) = v24\n\t"
> + "vmem(%1 + #0) = v25\n\t"
> + : : "r"(pout0), "r"(pout1)
> + : "r0", "v16", "v18", "v21", "v24", "v25", "memory"
> + );
> +
> + for (int i = 0; i < MAX_VEC_SIZE_BYTES / 4; ++i) {
> + expect[0].w[i] = 0x180c0000;
> + expect[1].w[i] = 0x000c1818;
> + }
> +
> + check_output_w(__LINE__, 2);
> +}
> +
> static void test_load_cur(void)
> {
> void *p0 = buffer0;
> @@ -435,6 +465,7 @@ int main()
> init_buffers();
>
> test_load_tmp();
> + test_load_tmp2();
> test_load_cur();
> test_load_aligned();
> test_load_unaligned();
> --
> 2.25.1
Reviewed-by: Brian Cain <bc...@quicinc.com>
