When inside a loop, treat any read of outer expressions to happen
multiple times, forcing a temporary of said outer expressions.
This avoids the problem where we can end up relying on loop-invariant code motion to happen in the
compiler when converting optimized shaders.
When we see a switch block which only contains one default block, emit a
do {} while(false) statement instead, which is far more idiomatic and
readable anyways.
If a buffer rewrites its Offsets, all member references to that struct
are invalidated, and must be redirected, do so in to_member_reference,
but there might be other places where this is needed. Fix as required.
SPIR-V code relying on this is somewhat questionable, but seems to be
in-spec.
- Fixes issue with clip_distance flattening in MSL where member to
flatten from would come from to_member_name, where it should have used
the builtin name directly. This member name was modified by this patch
and broke clip distance test shaders.
- Some cleanups with ir.meta, use ir.find_meta instead to not create
unnecessary hashmap nodes.
There is no direct way to express this, so invert boolean results to
force any NaN -> true. glslang emits Ordered compare instructions
everywhere, and the GLSL spec is not clear on this, so assume this is
fine.
It is possible for a shader to declare two plain struct types which
simply share the same OpName without there being an implicit
value/buffer alias relationship.
For to_member_name(), make sure to use the type alias master when
resolving member names. The member name may be different in a type alias
master if the SPIR-V is being intentionally difficult.
Rolled the hashes used for glslang, SPIRV-Tools, and SPIRV-Headers to
HEAD, which includes the update to 1.5.
Added passing '--amb' to glslang, so I didn't have to explicitly set
bindings in a large number of test shaders that currently don't, and
now glslang considers them invalid.
Marked all shaders that no longer pass spirv-val as .invalid.
When merging combined image samplers, we only looked at sampler, but DXC
emits RelaxedPrecision only for texture. Does not hurt to check for more
things.
Inner scope can still dominate here, so we need to be conservative when
we observe switch blocks specifically. Normal selection merges cannot
merge from multiple paths.
This is not necessary, as we must emit an invalidating store before we
potentially consume an invalid expression. In fact, we're a bit
conservative here in this case for example:
int tmp = variable;
if (...)
{
variable = 10;
}
else
{
// Consuming tmp here is fine, but it was
// invalidated while emitting other branch.
// Technically, we need to study if there is an invalidating store
// in the CFG between the loading block and this block, and the other
// branch will not be a part of that analysis.
int tmp2 = tmp * tmp;
}
Fixing this case means complex CFG traversal *everywhere*, and it feels like overkill.
Fixing this exposed a bug with access chains, so fix a bug where expression dependencies were not
inherited properly in access chains. Access chains are now considered forwarded if there
is at least one dependency which is also forwarded.
This subtle bug removed any expression validation for trivially swizzled
variables. Make usage suppression a more explicit concept rather than
just hacking off forwarded_temporaries.
There is some fallout here with loop generation since our expression
invalidation is currently a bit too naive to handle loops properly.
The forwarding bug masked this problem until now.
If part of the loop condition is also used in the body, we end up
reading an invalid expression, which in turn forces a temporary to be
generated in the condition block, not good. We'll need to be smarter
here ...
Make sure to test everything with scalar as well to catch any weird edge
cases.
Not all opcodes are covered here, just the arithmetic ones. FP64 packing
is also ignored.
This is quite complex since we cannot flush Phi inside the case labels,
we have to do it outside by emitting a lot of manual branches ourselves.
This should be extremely rare, but we need to handle this case.
