On Tuesday, July 21, 2015 07:54:14 PM Connor Abbott wrote: > Back when I was getting NIR up and running, I created a bunch of > functions that dealt with modifying control flow; they allowed you to > remove control flow nodes (if's, loops, and basic blocks) as well as > insert newly-created control flow nodes at certain points. The insertion > API's worked well enough for the usecase we had, which was building up > NIR while translating from something else, and the removal API found > some use in e.g. the select peephole. But there are various things we > want to do, some of which are becoming more and more urgent, which > involve doing more invasive modifications to the IR. To be able to do > these things, this series adds an API which is a little lower-level than > the existing one, but a lot less dangerous than manipulating things > directly. It uses most of the same internal machinery as the existing > functions, but I needed to rework it extensively to fix issues that were > usually obscure edges in the old code that become more important in the > new code. For more detail on the API itself and how to use it, see patch > 20. In addition, there are a few peripheral things that I did which are > related to the core objective of the series: > > - The control flow code was entangled with the rest of the code in > nir.c, and it was about to get larger, so I pulled it out into its own > file (nir_control_flow.c) and gave it its own header > (nir_control_flow.h). > > - The new API includes an extract function (for details see patch 20) > which needs to take begin and end points. There were going to be many > variants necessary for completeness, and even more for convenience, so > I decided to do something about it by creating a "cursor" structure. A > cursor is a small structure (8 bytes on a 32-bit system, 16 bytes on a > 64-bit system) that represents some point where something can be > inserted (before or after an instruction or before or after a block). > There are helpers for constructing cursors in all the relevant places, > and convenience helpers for creating cursors before/after a control > flow node and before/after a control flow list. That way, the need for > trivial nir_insert_thing_before/after_other_thing wrappers is gone, > and it's easy to add new convenience helpers for cursors which will > work with every API that uses a cursor. We probably want to use > cursors to simplify instruction insertion/deletion and the builder, > but I deferred that till later. > > The series was tested with an updated version of my dead control flow > elimination series, which I'm going to post shortly. > > The structure of the series is as follows: > > patch 01: adds a lot more checking of block predecessors and successors > in the validator, which is useful for checking the results of control > flow modification. > patch 02-03: prepares for splitting off the control flow code by getting > rid of as many dependencies as possible. > patch 04: moves the control flow code off to its own file. > patch 05-15: fix many different problems with the current control flow > code which will become more important when the new API is added. > patch 16-19: introduce the cursor helper, and make the old control flow > insertion API use it. > patch 20: actually adds the new API. > patch 21: removes the old, buggy implementation of nir_cf_node_remove() > and makes it a small wrapper around the new API instead. > > The series can also be found at: > > git://people.freedesktop.org/~cwabbott0/mesa nir-control-flow-mod > > Connor > > Connor Abbott (21): > nir/validate: check successors/predecessors more carefully > nir: inline block_add_pred() a few places > nir: make cleanup_cf_node() not use remove_defs_uses() > nir: move control flow modification to its own file > nir/cf: add insert_phi_undef() helper > nir: add nir_foreach_phi_src_safe() > nir/cf: add remove_phi_src() helper > nir/cf: split up and improve nir_handle_remove_jumps() > nir/cf: handle phi nodes better in split_block_beginning() > nir/cf: add block_ends_in_jump() > nir/cf: handle jumps in split_block_end() > nir/cf: handle jumps better in stitch_blocks() > nir/cf: remove uses of SSA definitions that are being deleted
Patches 1-13 (the above) are: Reviewed-by: Kenneth Graunke <kenn...@whitecape.org> I haven't gotten to the rest, and I'm not sure if I will in the next week...sorry :( Hopefully someone else can take a look and you can land this. > nir/cf: clean up jumps when cleaning up CF nodes > nir/cf: fix link_blocks() when there are no successors > nir/cf: add a cursor structure > nir/cf: add split_block_before_instr() > nir/cf: add split_block_cursor() > nir/cf: use a cursor for inserting control flow > nir/cf: add new control modification API's > nir/cf: reimplement nir_cf_node_remove() using the new API > > src/gallium/auxiliary/nir/tgsi_to_nir.c | 1 + > src/glsl/Makefile.sources | 3 + > src/glsl/nir/glsl_to_nir.cpp | 1 + > src/glsl/nir/nir.c | 680 +--------------------------- > src/glsl/nir/nir.h | 17 +- > src/glsl/nir/nir_control_flow.c | 773 > ++++++++++++++++++++++++++++++++ > src/glsl/nir/nir_control_flow.h | 252 +++++++++++ > src/glsl/nir/nir_control_flow_private.h | 38 ++ > src/glsl/nir/nir_opt_peephole_select.c | 1 + > src/glsl/nir/nir_validate.c | 95 +++- > 10 files changed, 1162 insertions(+), 699 deletions(-) > create mode 100644 src/glsl/nir/nir_control_flow.c > create mode 100644 src/glsl/nir/nir_control_flow.h > create mode 100644 src/glsl/nir/nir_control_flow_private.h > >
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