[Mesa-dev] [PATCH] i965/fs: Drop the emit(fs_inst) overload.

[Pohjolainen, Topi]

On Fri, Feb 21, 2014 at 03:23:42PM -0800, Kenneth Graunke wrote:
> Using this emit function implicitly creates three copies, which
> is pointlessly inefficient.
> 
> 1. Code creates the original instruction.
> 2. Calling emit(fs_inst) copies it into the function.
> 3. It then allocates a new fs_inst and copies it into that.
> 
> The second could be eliminated by changing the signature to
> 
>    fs_inst(const fs_inst &)
> 
> but that wouldn't eliminate the third.  Making callers heap allocate the
> instruction and call emit(fs_inst *) allows us to just use the original
> one, with no extra copies, and isn't much more of a burden.

Reviewed-by: Topi Pohjolainen <topi.pohjolainen at intel.com>

> 
> Cc: Matt Turner <mattst88 at gmail.com>
> Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
> ---
>  src/mesa/drivers/dri/i965/brw_fs.cpp         | 14 +++++++-------
>  src/mesa/drivers/dri/i965/brw_fs.h           |  1 -
>  src/mesa/drivers/dri/i965/brw_fs_visitor.cpp | 27 ++++++++++-----------------
>  3 files changed, 17 insertions(+), 25 deletions(-)
> 
> FAIL.  This is the patch I actually meant to send. :)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
> index 65f2c80..5af3397 100644
> --- a/src/mesa/drivers/dri/i965/brw_fs.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
> @@ -641,8 +641,8 @@ fs_visitor::emit_shader_time_write(enum shader_time_shader_type type,
>     else
>        payload = fs_reg(this, glsl_type::uint_type);
>  
> -   emit(fs_inst(SHADER_OPCODE_SHADER_TIME_ADD,
> -                fs_reg(), payload, offset, value));
> +   emit(new(mem_ctx) fs_inst(SHADER_OPCODE_SHADER_TIME_ADD,
> +                             fs_reg(), payload, offset, value));
>  }
>  
>  void
> @@ -671,32 +671,32 @@ fs_visitor::fail(const char *format, ...)
>  fs_inst *
>  fs_visitor::emit(enum opcode opcode)
>  {
> -   return emit(fs_inst(opcode));
> +   return emit(new(mem_ctx) fs_inst(opcode));
>  }
>  
>  fs_inst *
>  fs_visitor::emit(enum opcode opcode, fs_reg dst)
>  {
> -   return emit(fs_inst(opcode, dst));
> +   return emit(new(mem_ctx) fs_inst(opcode, dst));
>  }
>  
>  fs_inst *
>  fs_visitor::emit(enum opcode opcode, fs_reg dst, fs_reg src0)
>  {
> -   return emit(fs_inst(opcode, dst, src0));
> +   return emit(new(mem_ctx) fs_inst(opcode, dst, src0));
>  }
>  
>  fs_inst *
>  fs_visitor::emit(enum opcode opcode, fs_reg dst, fs_reg src0, fs_reg src1)
>  {
> -   return emit(fs_inst(opcode, dst, src0, src1));
> +   return emit(new(mem_ctx) fs_inst(opcode, dst, src0, src1));
>  }
>  
>  fs_inst *
>  fs_visitor::emit(enum opcode opcode, fs_reg dst,
>                   fs_reg src0, fs_reg src1, fs_reg src2)
>  {
> -   return emit(fs_inst(opcode, dst, src0, src1, src2));
> +   return emit(new(mem_ctx) fs_inst(opcode, dst, src0, src1, src2));
>  }
>  
>  void
> diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h
> index b1e38b6..ebf90a3 100644
> --- a/src/mesa/drivers/dri/i965/brw_fs.h
> +++ b/src/mesa/drivers/dri/i965/brw_fs.h
> @@ -282,7 +282,6 @@ public:
>  
>     bool can_do_source_mods(fs_inst *inst);
>  
> -   fs_inst *emit(fs_inst inst);
>     fs_inst *emit(fs_inst *inst);
>     void emit(exec_list list);
>  
> diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
> index aea3360..b1e795e 100644
> --- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
> @@ -741,8 +741,8 @@ fs_visitor::visit(ir_expression *ir)
>           packed_consts.type = result.type;
>  
>           fs_reg const_offset_reg = fs_reg(const_offset->value.u[0] & ~15);
> -         emit(fs_inst(FS_OPCODE_UNIFORM_PULL_CONSTANT_LOAD,
> -                      packed_consts, surf_index, const_offset_reg));
> +         emit(new(mem_ctx) fs_inst(FS_OPCODE_UNIFORM_PULL_CONSTANT_LOAD,
> +                                   packed_consts, surf_index, const_offset_reg));
>  
>           for (int i = 0; i < ir->type->vector_elements; i++) {
>              packed_consts.set_smear(const_offset->value.u[0] % 16 / 4 + i);
> @@ -2397,9 +2397,10 @@ fs_visitor::emit_untyped_atomic(unsigned atomic_op, unsigned surf_index,
>     }
>  
>     /* Emit the instruction. */
> -   fs_inst inst(SHADER_OPCODE_UNTYPED_ATOMIC, dst, atomic_op, surf_index);
> -   inst.base_mrf = 0;
> -   inst.mlen = mlen;
> +   fs_inst *inst = new(mem_ctx) fs_inst(SHADER_OPCODE_UNTYPED_ATOMIC, dst,
> +                                        atomic_op, surf_index);
> +   inst->base_mrf = 0;
> +   inst->mlen = mlen;
>     emit(inst);
>  }
>  
> @@ -2430,22 +2431,14 @@ fs_visitor::emit_untyped_surface_read(unsigned surf_index, fs_reg dst,
>     mlen += operand_len;
>  
>     /* Emit the instruction. */
> -   fs_inst inst(SHADER_OPCODE_UNTYPED_SURFACE_READ, dst, surf_index);
> -   inst.base_mrf = 0;
> -   inst.mlen = mlen;
> +   fs_inst *inst = new(mem_ctx)
> +      fs_inst(SHADER_OPCODE_UNTYPED_SURFACE_READ, dst, surf_index);
> +   inst->base_mrf = 0;
> +   inst->mlen = mlen;
>     emit(inst);
>  }
>  
>  fs_inst *
> -fs_visitor::emit(fs_inst inst)
> -{
> -   fs_inst *list_inst = new(mem_ctx) fs_inst;
> -   *list_inst = inst;
> -   emit(list_inst);
> -   return list_inst;
> -}
> -
> -fs_inst *
>  fs_visitor::emit(fs_inst *inst)
>  {
>     if (force_uncompressed_stack > 0)
> -- 
> 1.9.0
> 
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