On Thu, 2019-03-14 at 11:25 -0500, Jason Ekstrand wrote:
> Looking at this a bit more, I'm not sure that just short-circuiting actually
> covers all the cases. Unfortunately, we don't know what all the cases are
> because the SPIR-V spec doesn't say. I'm trying to work towards fixing that
> right now.
>
>
Did you have time to check this?
J.A.
> --Jason
>
>
> On Wed, Mar 6, 2019 at 5:25 AM Juan A. Suarez Romero <jasua...@igalia.com>
> wrote:
> > This fixes the case when the SPIR-V code has two nested conditional
> >
> > branches, but only one selection merge:
> >
> >
> >
> > [...]
> >
> > %1 = OpLabel
> >
> > OpSelectionMerge %2 None
> >
> > OpBranchConditional %3 %4 %2
> >
> > %4 = OpLabel
> >
> > OpBranchConditional %3 %5 %2
> >
> > %5 = OpLabel
> >
> > OpBranch %2
> >
> > %2 = OpLabel
> >
> > [...]
> >
> >
> >
> > In the second OpBranchConditional, as the else-part is the end
> >
> > block (started in the first OpBranchConditional) we can just follow the
> >
> > then-part.
> >
> >
> >
> > This fixes dEQP-VK.vkrunner.controlflow.2-obc-triangle-triangle
> >
> >
> >
> > CC: Jason Ekstrand <ja...@jlekstrand.net>
> >
> > ---
> >
> > src/compiler/spirv/vtn_cfg.c | 11 ++++++++++-
> >
> > 1 file changed, 10 insertions(+), 1 deletion(-)
> >
> >
> >
> > diff --git a/src/compiler/spirv/vtn_cfg.c b/src/compiler/spirv/vtn_cfg.c
> >
> > index 7868eeb60bc..f749118efbe 100644
> >
> > --- a/src/compiler/spirv/vtn_cfg.c
> >
> > +++ b/src/compiler/spirv/vtn_cfg.c
> >
> > @@ -605,7 +605,16 @@ vtn_cfg_walk_blocks(struct vtn_builder *b, struct
> > list_head *cf_list,
> >
> > }
> >
> > } else if (if_stmt->then_type == vtn_branch_type_none &&
> >
> > if_stmt->else_type == vtn_branch_type_none) {
> >
> > - /* Neither side of the if is something we can short-circuit. */
> >
> > + /* Neither side of the if is something we can short-circuit,
> >
> > + * unless one of the blocks is the end block. */
> >
> > + if (then_block == end) {
> >
> > + block = else_block;
> >
> > + continue;
> >
> > + } else if (else_block == end) {
> >
> > + block = then_block;
> >
> > + continue;
> >
> > + }
> >
> > +
> >
> > vtn_assert((*block->merge & SpvOpCodeMask) ==
> > SpvOpSelectionMerge);
> >
> > struct vtn_block *merge_block =
> >
> > vtn_value(b, block->merge[1], vtn_value_type_block)->block;
> >
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