This lowering pass generates GLSL code that manually packs varyings
into vec4 slots, for the benefit of back-ends that don't support
packed varyings natively.
No functional change--the lowering pass is not yet used.
Reviewed-by: Eric Anholt <eric@anholt.net>
v2: Don't use ir_hierarchical_visitor--just loop over instructions
directly. Also, make the names of the packed varyings include the
names of the original varyings that were packed into them.
This patch modifies the clip distance lowering pass so that the new
symbol it generates (glClipDistanceMESA) is added to the shader's
symbol table.
This will allow a later patch to modify the linker so that it finds
transform feedback varyings using the symbol table rather than having
to iterate through all the declarations in the shader.
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
v2: Reduce the impenetrable code in emit_ubo_loads() by 23 lines by keeping
the ir_variable as the variable part of the offset from handle_rvalue(),
and track the constant offsets from that with a plain old integer value,
avoiding a bunch of temporary variables in the array and struct handling.
Also, fix file description doxygen.
v3: Fix a row vs col typo, and fix spelling in a comment.
Reviewed-by: Eric Anholt <eric@anholt.net>
Previously, I tried implementing this in the i965 driver, but did so
in a way that violated the intent of the spec, and broke Tropics.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
I've had this code laying around almost done for a long time. The
idea is like opt_structure_splitting, that we've got a bunch of
transforms at the GLSL IR level that only understand scalars and
vectors, which just skip complicated dereferences. While driver
backends may manage some optimization after they split matrices up
themselves, it would be better to bring all of our optimization to
bear on the problem.
While I wasn't expecting changes quite yet, a few programs end up
winning: a gstreamer convolution shader, and the Humus dynamic
branching demo:
Total instructions: 269430 -> 269342
3/2148 programs affected (0.1%)
1498 -> 1410 instructions in affected programs (5.9% reduction)
This is similar to Gallium's existing glsl_to_tgsi::remove_output_read
lowering pass, but done entirely inside the GLSL compiler.
Signed-off-by: Vincent Lejeune <vljn@ovi.com>
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
In i965 GEN6+ (and I suspect most other hardware), gl_ClipDistance
needs to be laid out as a pair of vec4's (the first containing clip
distances 0-3, and the second containing clip distances 4-7).
However, it is declared in GLSL as an array of 8 floats.
This lowering pass acts at the GLSL level, modifying the declaration
of gl_ClipDistance so that it is an array of vec4's rather than an
array of floats, and renaming it to gl_ClipDistanceMESA. In addition,
it modifies all accesses to the array so that they access the
appropiate component of one of the vec4's.
Since some hardware may not internally represent gl_ClipDistance as a
pair of vec4's, this lowering pass is optional. To enable it, set the
LowerClipDistance flag in gl_shader_compiler_options to true.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Using multiply and reciprocal for integer division involves potentially
lossy floating point conversions. This is okay for older GPUs that
represent integers as floating point, but undesirable for GPUs with
native integer division instructions.
TGSI, for example, has UDIV/IDIV instructions for integer division,
so it makes sense to handle this directly. Likewise for i965.
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Signed-off-by: Bryan Cain <bryancain3@gmail.com>
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
This patch cleans up many of the extra copies in GLSL IR introduced by
i965's scalarizing passes. It doesn't result in a statistically
significant performance difference on nexuiz high settings (n=3) or my
demo (n=10), due to brw_fs.cpp's register coalescing covering most of
those extra moves anyway. However, it does make the debug of wine's
GLSL shaders much more tractable, and reduces instruction count of
glsl-fs-convolution-2 from 376 to 288.
This adds a new optional max_depth parameter (defaulting to 0) to
lower_if_to_cond_assign, and makes the pass only flatten if-statements
nested deeper than that.
By default, all if-statements will be flattened, just like before.
This patch also renames do_if_to_cond_assign to lower_if_to_cond_assign,
to match the new naming conventions.
This should allow lower_if_to_cond_assign to work in the presence of
discards, fixing bug #31690 and likely #31983.
NOTE: This is a candidate for the 7.9 branch.
This should save on the overhead of tree-walking and provide a
convenient place to add more instruction lowering in the future.
Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
The vector operator collects 2, 3, or 4 scalar components into a
vector. Doing this has several advantages. First, it will make
ud-chain tracking for components of vectors much easier. Second, a
later optimization pass could collect scalars into vectors to allow
generation of SWZ instructions (or similar as operands to other
instructions on R200 and i915). It also enables an easy way to
generate IR for SWZ instructions in the ARB_vertex_program assembler.
Currenly GLSL happily generates indirect addressing of any kind of
arrays.
Unfortunately DirectX 9 GPUs are not guaranteed to support any of them in
general.
This pass fixes that by lowering such constructs to a binary search on the
values, followed at the end by vectorized generation of equality masks, and
4 conditional assignments for each mask generation.
Note that this requires the ir_binop_equal change so that we can emit SEQ
to generate the boolean masks.
Unfortunately, ir_structure_splitting is too dumb to turn the resulting
constant array references to individual variables, so this will need to
be added too before this pass can actually be effective for temps.
Several patches in the glsl2-lower-variable-indexing were squashed
into this commit. These patches fix bugs in Luca's original
implementation, and the individual patches can be seen in that branch.
This was done to aid bisecting in the future.
Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Changes in v2:
- Base class renamed to ir_control_flow_visitor
- Tried to comply with coding style
This is a new pass that supersedes ir_if_return and "lowers" jumps
to if/else structures.
Currently it causes no regressions on softpipe and nv40, but I'm not sure
whether the piglit glsl tests are thorough enough, so consider this
experimental.
It can be asked to:
1. Pull jumps out of ifs where possible
2. Remove all "continue"s, replacing them with an "execute flag"
3. Replace all "break" with a single conditional one at the end of the loop
4. Replace all "return"s with a single return at the end of the function,
for the main function and/or other functions
This gives several great benefits:
1. All functions can be inlined after this pass
2. nv40 and other pre-DX10 chips without "continue" can be supported
3. nv30 and other pre-DX10 chips with no control flow at all are better supported
Note that for full effect we should also teach the unroller to unroll
loops with a fixed maximum number of iterations but with the canonical
conditional "break" that this pass will insert if asked to.
Continues are lowered by adding a per-loop "execute flag", initialized to
TRUE, that when cleared inhibits all execution until the end of the loop.
Breaks are lowered to continues, plus setting a "break flag" that is checked
at the end of the loop, and trigger the unique "break".
Returns are lowered to breaks/continues, plus adding a "return flag" that
causes loops to break again out of their enclosing loops until all the
loops are exited: then the "execute flag" logic will ignore everything
until the end of the function.
Note that "continue" and "return" can also be implemented by adding
a dummy loop and using break.
However, this is bad for hardware with limited nesting depth, and
prevents further optimization, and thus is not currently performed.
This increases the chance that GLSL programs will actually work.
Note that continues and returns are not yet lowered, so linking
will just fail if not supported.
Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
With the glsl2-965 branch, the optimization of glsl-algebraic-rcp-rcp
regressed due to noop swizzles hiding information from ir_algebraic.
This cleans up those noop swizzles for us.
All the current HW backends transform subtract to adding the negation,
so I haven't bothered peepholing it back out in Mesa IR. This allows
some subtract of subtract to get removed in ir_algebraic.
Whereas constant folding evaluates constant expressions at rvalue
nodes, constant propagation tracks constant components of vectors
across execution to replace (possibly swizzled) variable dereferences
with constant values, triggering possible constant folding or reduced
variable liveness.
Fixes ir_to_mesa handling of unop_log, which used the weird ARB_vp LOG
opcode that doesn't do what we want. This also lets the multiplication
coefficients in there get constant-folded, possibly.
Fixes:
glsl-fs-log
This doesn't do anything if your structure goes through an uninlined
function call or if whole-structure assignment occurs. As such, the
impact is limited, at least until we do some global copy propagation
to reduce whole-structure assignment.
For a shader involving many small functions, this avoids running
optimization across all of them after they've been inlined
post-linking.
Reduces the runtime of linking and running a fragment shader from Yo
Frankie from 1.6 seconds to 0.9 seconds (-44.9%, +/- 3.3%).
This cleans up the assembly output of almost all the non-logic tests
glsl-algebraic-*. glsl-algebraic-pow-two needs love (basically,
flattening to a temporary and squaring it).
This will be used by the Mesa IR and likely most HW backends, as it
allows other optimizations to occur that might not otherwise.
Fixes glsl-vs-mat-sub-1, glsl-vs-mat-div-1.
This allows function inlining making the following tests work even
without function calls implemented:
glsl-fs-functions-2
glsl-fs-functions-3
glsl-vs-functions
glsl-vs-functions-2
glsl-vs-functions-3
glsl-vs-vec4-indexing-5
(Note that those tests were designed to trigger actual function calls,
and this defeats them. However, those testcases ended up catching the
bug in the previous commit.)
The Mesa IR needs this to support vector indexing correctly, and
hardware backends such as 915 would want this behavior as well.
Fixes glsl-vs-vec4-indexing-2.
