Ian Romanick <i...@freedesktop.org> writes:
> From: Ian Romanick <ian.d.roman...@intel.com>
>
> On BDW,
>
> total instructions in shared programs: 8448571 -> 8448367 (-0.00%)
> instructions in affected programs: 21000 -> 20796 (-0.97%)
> helped: 116
> HURT: 0
>
> Signed-off-by: Ian Romanick <ian.d.roman...@intel.com>
> ---
> src/mesa/drivers/dri/i965/brw_dead_control_flow.cpp | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/src/mesa/drivers/dri/i965/brw_dead_control_flow.cpp
> b/src/mesa/drivers/dri/i965/brw_dead_control_flow.cpp
> index 7aa72b1..149596f 100644
> --- a/src/mesa/drivers/dri/i965/brw_dead_control_flow.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_dead_control_flow.cpp
> @@ -34,6 +34,7 @@
> * - if/endif
> * . else in else/endif
> * - if/else/endif
> + * - then in if/else/endif
> */
> bool
> dead_control_flow_eliminate(backend_shader *s)
> @@ -114,6 +115,23 @@ dead_control_flow_eliminate(backend_shader *s)
>
> progress = true;
> }
> + } else if (inst->opcode == BRW_OPCODE_ELSE &&
> + prev_inst->opcode == BRW_OPCODE_IF) {
> + bblock_t *const else_block = block;
> + bblock_t *const if_block = prev_block;
> + backend_instruction *const if_inst = prev_inst;
> + backend_instruction *const else_inst = inst;
> +
> + /* Since the else-branch is becoming the new then-branch, the
> + * condition has to be inverted.
> + */
> + if_inst->predicate_inverse = !if_inst->predicate_inverse;
> + else_inst->remove(else_block);
> +
> + if (if_block->can_combine_with(else_block))
> + if_block->combine_with(else_block);Ugh, IIRC backend_instruction::remove(block) will remove the block behind your back when it becomes empty (and it will here because ELSE can only be the only instruction left inside 'block' whenever you hit this path), so you're passing a pointer to a no-longer-existing block to (can_)combine_with(). I believe this will never let you combine the blocks anyway because the previous block ends with an IF instruction which you haven't removed, so this is effectively a no-op [assuming it doesn't crash ;)]. If you drop the two lines above you can put my Reviewed-by: Francisco Jerez <curroje...@riseup.net> on this patch and the rest of the series. > + > + progress = true; > } > } > > -- > 2.5.0 > > _______________________________________________ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/mesa-dev
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