Currently, the testing infrastructure for SPIR-V is based on FileCheck.
Those tests are great to check some level of codegen, but when the test
needs check both the CFG layout and the content of each basic-block,
things becomes messy.
- Because the CHECK/CHECK-DAG/CHECK-NEXT state is limited, it is
sometimes hard to catch the good block: if 2 basic blocks have similar
instructions, FileCheck can match the wrong one.
- Cross-lane interaction can be a bit difficult to understand, and
writting a FileCheck test that is strong enough to catch bad CFG
transforms while not being broken everytime some unrelated codegen part
changes is hard.
And lastly, the spirv-val tooling we have checks that the generated
SPIR-V respects the spec, not that it is correct in regards to the
source IR.
For those reasons, I believe the best way to test the structurizer is
to:
- run spirv-val to make sure the CFG respects the spec.
- simulate the function to validate result for each lane, making sure
the generated code is correct.
This simulator has no other dependencies than core python. It also only
supports a very limited set of instructions as we can test most features
through control-flow and some basic cross-lane interactions.
As-is, the added tests are just a harness for the simulator itself. If
this gets merged, the structurizer PR will benefit from this as I'll be
able to add extensive testing using this.
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Signed-off-by: Nathan Gauër <brioche@google.com>
c3d8124617