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From: David Hildenbrand <david@redhat.com>
To: Richard Henderson <richard.henderson@linaro.org>, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 02/38] tcg: Assert fixed_reg is read-only
Date: Tue, 23 Apr 2019 10:03:59 +0200	[thread overview]
Message-ID: <834f5c7b-c6b5-87b8-2154-3a3875726343@redhat.com> (raw)
In-Reply-To: <20190420073442.7488-3-richard.henderson@linaro.org>

On 20.04.19 09:34, Richard Henderson wrote:
> The only fixed_reg is cpu_env, and it should not be modified
> during any TB.  Therefore code that tries to special-case moves
> into a fixed_reg is dead.  Remove it.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  tcg/tcg.c | 85 +++++++++++++++++++++++++------------------------------
>  1 file changed, 38 insertions(+), 47 deletions(-)
> 
> diff --git a/tcg/tcg.c b/tcg/tcg.c
> index ade6050982..4f77a957b0 100644
> --- a/tcg/tcg.c
> +++ b/tcg/tcg.c
> @@ -3279,11 +3279,8 @@ static void tcg_reg_alloc_do_movi(TCGContext *s, TCGTemp *ots,
>                                    tcg_target_ulong val, TCGLifeData arg_life,
>                                    TCGRegSet preferred_regs)
>  {
> -    if (ots->fixed_reg) {
> -        /* For fixed registers, we do not do any constant propagation.  */
> -        tcg_out_movi(s, ots->type, ots->reg, val);
> -        return;
> -    }
> +    /* ENV should not be modified.  */
> +    tcg_debug_assert(!ots->fixed_reg);
>  
>      /* The movi is not explicitly generated here.  */
>      if (ots->val_type == TEMP_VAL_REG) {
> @@ -3319,6 +3316,9 @@ static void tcg_reg_alloc_mov(TCGContext *s, const TCGOp *op)
>      ots = arg_temp(op->args[0]);
>      ts = arg_temp(op->args[1]);
>  
> +    /* ENV should not be modified.  */
> +    tcg_debug_assert(!ots->fixed_reg);
> +
>      /* Note that otype != itype for no-op truncation.  */
>      otype = ots->type;
>      itype = ts->type;
> @@ -3343,7 +3343,7 @@ static void tcg_reg_alloc_mov(TCGContext *s, const TCGOp *op)
>      }
>  
>      tcg_debug_assert(ts->val_type == TEMP_VAL_REG);
> -    if (IS_DEAD_ARG(0) && !ots->fixed_reg) {
> +    if (IS_DEAD_ARG(0)) {
>          /* mov to a non-saved dead register makes no sense (even with
>             liveness analysis disabled). */
>          tcg_debug_assert(NEED_SYNC_ARG(0));
> @@ -3356,7 +3356,7 @@ static void tcg_reg_alloc_mov(TCGContext *s, const TCGOp *op)
>          }
>          temp_dead(s, ots);
>      } else {
> -        if (IS_DEAD_ARG(1) && !ts->fixed_reg && !ots->fixed_reg) {
> +        if (IS_DEAD_ARG(1) && !ts->fixed_reg) {
>              /* the mov can be suppressed */
>              if (ots->val_type == TEMP_VAL_REG) {
>                  s->reg_to_temp[ots->reg] = NULL;
> @@ -3509,6 +3509,10 @@ static void tcg_reg_alloc_op(TCGContext *s, const TCGOp *op)
>              arg = op->args[i];
>              arg_ct = &def->args_ct[i];
>              ts = arg_temp(arg);
> +
> +            /* ENV should not be modified.  */
> +            tcg_debug_assert(!ts->fixed_reg);
> +
>              if ((arg_ct->ct & TCG_CT_ALIAS)
>                  && !const_args[arg_ct->alias_index]) {
>                  reg = new_args[arg_ct->alias_index];
> @@ -3517,29 +3521,19 @@ static void tcg_reg_alloc_op(TCGContext *s, const TCGOp *op)
>                                      i_allocated_regs | o_allocated_regs,
>                                      op->output_pref[k], ts->indirect_base);
>              } else {
> -                /* if fixed register, we try to use it */
> -                reg = ts->reg;
> -                if (ts->fixed_reg &&
> -                    tcg_regset_test_reg(arg_ct->u.regs, reg)) {
> -                    goto oarg_end;
> -                }
>                  reg = tcg_reg_alloc(s, arg_ct->u.regs, o_allocated_regs,
>                                      op->output_pref[k], ts->indirect_base);
>              }
>              tcg_regset_set_reg(o_allocated_regs, reg);
> -            /* if a fixed register is used, then a move will be done afterwards */
> -            if (!ts->fixed_reg) {
> -                if (ts->val_type == TEMP_VAL_REG) {
> -                    s->reg_to_temp[ts->reg] = NULL;
> -                }
> -                ts->val_type = TEMP_VAL_REG;
> -                ts->reg = reg;
> -                /* temp value is modified, so the value kept in memory is
> -                   potentially not the same */
> -                ts->mem_coherent = 0;
> -                s->reg_to_temp[reg] = ts;
> +            if (ts->val_type == TEMP_VAL_REG) {
> +                s->reg_to_temp[ts->reg] = NULL;
>              }
> -        oarg_end:
> +            ts->val_type = TEMP_VAL_REG;
> +            ts->reg = reg;
> +            /* temp value is modified, so the value kept in memory is
> +               potentially not the same */
> +            ts->mem_coherent = 0;
> +            s->reg_to_temp[reg] = ts;
>              new_args[i] = reg;
>          }
>      }
> @@ -3555,10 +3549,10 @@ static void tcg_reg_alloc_op(TCGContext *s, const TCGOp *op)
>      /* move the outputs in the correct register if needed */
>      for(i = 0; i < nb_oargs; i++) {
>          ts = arg_temp(op->args[i]);
> -        reg = new_args[i];
> -        if (ts->fixed_reg && ts->reg != reg) {
> -            tcg_out_mov(s, ts->type, ts->reg, reg);
> -        }
> +
> +        /* ENV should not be modified.  */
> +        tcg_debug_assert(!ts->fixed_reg);
> +
>          if (NEED_SYNC_ARG(i)) {
>              temp_sync(s, ts, o_allocated_regs, 0, IS_DEAD_ARG(i));
>          } else if (IS_DEAD_ARG(i)) {
> @@ -3679,26 +3673,23 @@ static void tcg_reg_alloc_call(TCGContext *s, TCGOp *op)
>      for(i = 0; i < nb_oargs; i++) {
>          arg = op->args[i];
>          ts = arg_temp(arg);
> +
> +        /* ENV should not be modified.  */
> +        tcg_debug_assert(!ts->fixed_reg);
> +
>          reg = tcg_target_call_oarg_regs[i];
>          tcg_debug_assert(s->reg_to_temp[reg] == NULL);
> -
> -        if (ts->fixed_reg) {
> -            if (ts->reg != reg) {
> -                tcg_out_mov(s, ts->type, ts->reg, reg);
> -            }
> -        } else {
> -            if (ts->val_type == TEMP_VAL_REG) {
> -                s->reg_to_temp[ts->reg] = NULL;
> -            }
> -            ts->val_type = TEMP_VAL_REG;
> -            ts->reg = reg;
> -            ts->mem_coherent = 0;
> -            s->reg_to_temp[reg] = ts;
> -            if (NEED_SYNC_ARG(i)) {
> -                temp_sync(s, ts, allocated_regs, 0, IS_DEAD_ARG(i));
> -            } else if (IS_DEAD_ARG(i)) {
> -                temp_dead(s, ts);
> -            }
> +        if (ts->val_type == TEMP_VAL_REG) {
> +            s->reg_to_temp[ts->reg] = NULL;
> +        }
> +        ts->val_type = TEMP_VAL_REG;
> +        ts->reg = reg;
> +        ts->mem_coherent = 0;
> +        s->reg_to_temp[reg] = ts;
> +        if (NEED_SYNC_ARG(i)) {
> +            temp_sync(s, ts, allocated_regs, 0, IS_DEAD_ARG(i));
> +        } else if (IS_DEAD_ARG(i)) {
> +            temp_dead(s, ts);
>          }
>      }
>  }
> 

Reviewed-by: David Hildenbrand <david@redhat.com>

-- 

Thanks,

David / dhildenb

  parent reply	other threads:[~2019-04-23  8:04 UTC|newest]

Thread overview: 138+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-20  7:34 [Qemu-devel] [PATCH 00/38] tcg vector improvements Richard Henderson
2019-04-20  7:34 ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 01/38] target/arm: Fill in .opc for cmtst_op Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-23  8:00   ` David Hildenbrand
2019-04-23  8:00     ` David Hildenbrand
2019-04-20  7:34 ` [Qemu-devel] [PATCH 02/38] tcg: Assert fixed_reg is read-only Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-23  8:03   ` David Hildenbrand [this message]
2019-04-23  8:03     ` David Hildenbrand
2019-04-20  7:34 ` [Qemu-devel] [PATCH 03/38] tcg: Return bool success from tcg_out_mov Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20 10:56   ` Philippe Mathieu-Daudé
2019-04-20 10:56     ` Philippe Mathieu-Daudé
2019-04-23  8:27   ` David Hildenbrand
2019-04-23  8:27     ` David Hildenbrand
2019-04-20  7:34 ` [Qemu-devel] [PATCH 04/38] tcg: Support cross-class moves without instruction support Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-23  8:29   ` David Hildenbrand
2019-04-23  8:29     ` David Hildenbrand
2019-04-20  7:34 ` [Qemu-devel] [PATCH 05/38] tcg: Allow add_vec, sub_vec, neg_vec, not_vec to be expanded Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-23  8:33   ` David Hildenbrand
2019-04-23  8:33     ` David Hildenbrand
2019-04-20  7:34 ` [Qemu-devel] [PATCH 06/38] tcg: Promote tcg_out_{dup, dupi}_vec to backend interface Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 07/38] tcg: Manually expand INDEX_op_dup_vec Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 08/38] tcg: Add tcg_out_dupm_vec to the backend interface Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 09/38] tcg/i386: Implement tcg_out_dupm_vec Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 10/38] tcg/aarch64: " Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 11/38] tcg: Add INDEX_op_dup_mem_vec Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 12/38] tcg: Add gvec expanders for variable shift Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-23 19:04   ` David Hildenbrand
2019-04-23 19:04     ` David Hildenbrand
2019-04-23 19:28     ` Richard Henderson
2019-04-23 19:28       ` Richard Henderson
2019-04-23 21:02       ` David Hildenbrand
2019-04-23 21:02         ` David Hildenbrand
2019-04-23 21:40         ` Richard Henderson
2019-04-23 21:40           ` Richard Henderson
2019-04-23 21:57           ` David Hildenbrand
2019-04-23 21:57             ` David Hildenbrand
2019-04-20  7:34 ` [Qemu-devel] [PATCH 13/38] tcg/i386: Support vector variable shift opcodes Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 14/38] tcg/aarch64: " Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 15/38] tcg: Implement tcg_gen_gvec_3i() Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 16/38] tcg: Specify optional vector requirements with a list Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 17/38] tcg: Add gvec expanders for vector shift by scalar Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-23 18:58   ` David Hildenbrand
2019-04-23 18:58     ` David Hildenbrand
2019-04-23 19:21     ` Richard Henderson
2019-04-23 19:21       ` Richard Henderson
2019-04-23 21:05       ` David Hildenbrand
2019-04-23 21:05         ` David Hildenbrand
2019-04-20  7:34 ` [Qemu-devel] [PATCH 18/38] tcg/i386: Support vector scalar shift opcodes Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 19/38] tcg: Add support for integer absolute value Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-23  8:52   ` Philippe Mathieu-Daudé
2019-04-23  8:52     ` Philippe Mathieu-Daudé
2019-04-23 18:37   ` David Hildenbrand
2019-04-23 18:37     ` David Hildenbrand
2019-04-23 22:09     ` Philippe Mathieu-Daudé
2019-04-23 22:09       ` Philippe Mathieu-Daudé
2019-04-23 22:29       ` Richard Henderson
2019-04-23 22:29         ` Richard Henderson
2019-04-23 23:05         ` Philippe Mathieu-Daudé
2019-04-23 23:05           ` Philippe Mathieu-Daudé
2019-04-20  7:34 ` [Qemu-devel] [PATCH 20/38] tcg: Add support for vector " Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-23 18:35   ` David Hildenbrand
2019-04-23 18:35     ` David Hildenbrand
2019-04-20  7:34 ` [Qemu-devel] [PATCH 21/38] target/arm: Use tcg_gen_abs_i64 and tcg_gen_gvec_abs Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 22/38] target/cris: Use tcg_gen_abs_tl Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-23 10:09   ` Philippe Mathieu-Daudé
2019-04-23 10:09     ` Philippe Mathieu-Daudé
2019-04-20  7:34 ` [Qemu-devel] [PATCH 23/38] target/ppc: " Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 24/38] target/s390x: Use tcg_gen_abs_i64 Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-23 18:40   ` David Hildenbrand
2019-04-23 18:40     ` David Hildenbrand
2019-04-23 22:12   ` Philippe Mathieu-Daudé
2019-04-23 22:12     ` Philippe Mathieu-Daudé
2019-04-20  7:34 ` [Qemu-devel] [PATCH 25/38] target/xtensa: Use tcg_gen_abs_i32 Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-23 22:14   ` Philippe Mathieu-Daudé
2019-04-23 22:14     ` Philippe Mathieu-Daudé
2019-04-20  7:34 ` [Qemu-devel] [PATCH 26/38] tcg/i386: Support vector absolute value Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 27/38] tcg/aarch64: " Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 28/38] tcg: Add support for vector comparison select Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 29/38] tcg/i386: Support vector comparison select value Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 30/38] tcg/aarch64: " Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 31/38] target/ppc: Use vector variable shifts for VS{L, R, RA}{B, H, W, D} Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 32/38] target/arm: Vectorize USHL and SSHL Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 33/38] tcg/aarch64: Do not advertise minmax for MO_64 Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 34/38] tcg: Do not recreate INDEX_op_neg_vec unless supported Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 35/38] tcg: Introduce do_op3_nofail for vector expansion Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 36/38] tcg: Expand vector minmax using cmp+cmpsel Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 37/38] tcg/aarch64: Use MVNI for expansion of dupi Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  7:34 ` [Qemu-devel] [PATCH 38/38] tcg/aarch64: Use ORRI and BICI for vector logical operations Richard Henderson
2019-04-20  7:34   ` Richard Henderson
2019-04-20  8:09 ` [Qemu-devel] [PATCH 00/38] tcg vector improvements no-reply
2019-04-20  8:09   ` no-reply
2019-04-23 19:15 ` David Hildenbrand
2019-04-23 19:15   ` David Hildenbrand
2019-04-23 20:26   ` Richard Henderson
2019-04-23 20:26     ` Richard Henderson
2019-04-23 20:31     ` David Hildenbrand
2019-04-23 20:31       ` David Hildenbrand
2019-04-29 19:28 ` David Hildenbrand
2019-04-29 19:28   ` David Hildenbrand
2019-04-29 20:19   ` Richard Henderson
2019-04-29 20:19     ` Richard Henderson

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