[Mesa-dev] [PATCH 18/20] i965/fs: Preserve CFG in the SEL peephole.

[Pohjolainen, Topi]

On Mon, Aug 18, 2014 at 10:42:26AM -0700, Matt Turner wrote:
> On Mon, Aug 18, 2014 at 8:34 AM, Pohjolainen, Topi
> <topi.pohjolainen at intel.com> wrote:
> > On Thu, Jul 24, 2014 at 07:54:25PM -0700, Matt Turner wrote:
> >> ---
> >>  src/mesa/drivers/dri/i965/brw_fs_sel_peephole.cpp | 15 +++++++++------
> >>  1 file changed, 9 insertions(+), 6 deletions(-)
> >>
> >> diff --git a/src/mesa/drivers/dri/i965/brw_fs_sel_peephole.cpp b/src/mesa/drivers/dri/i965/brw_fs_sel_peephole.cpp
> >> index d64cd98..f609138 100644
> >> --- a/src/mesa/drivers/dri/i965/brw_fs_sel_peephole.cpp
> >> +++ b/src/mesa/drivers/dri/i965/brw_fs_sel_peephole.cpp
> >> @@ -212,23 +212,26 @@ fs_visitor::opt_peephole_sel()
> >>        if (brw->gen == 6 && if_inst->conditional_mod) {
> >>           fs_inst *cmp_inst = CMP(reg_null_d, if_inst->src[0], if_inst->src[1],
> >>                                   if_inst->conditional_mod);
> >> -         if_inst->insert_before(cmp_inst);
> >> +         if_inst->insert_before(block, cmp_inst);
> >>        }
> >>
> >> +      bblock_t *then_block = (bblock_t *)block->link.next;
> >> +      bblock_t *else_block = (bblock_t *)block->else_block->link.next;
> >
> > Isn't this a pointer to the endif-block? I thought else-block would be
> >
> >          bblock_t *else_block = (bblock_t *)block->then_block->link.next;
> >
> > or simply just
> >
> >          bblock_t *else_block = (bblock_t *)block->else_block;
> 
> It's the block immediately following the ELSE instruction (containing
> the MOVs). E.g.,
> 
> B0: ...
>     IF
> B1: MOV
>     MOV
>     ELSE
> B2: MOV
>     MOV
> B3: ENDIF
>     ...
> 
> then_block is B1, and else_block is B2. I can name them something else
> if that would make it clearer.

Thanks for the explanation, makes sense. I should have paid more attention to
the context and not just stared the name. If you can come up with a better
name though that would be nice (I cannot think of anything - "else_body_block"
sounds awful).

Either way:

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