Extend Spilling #143
Extend Spilling #143
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slothy/core/config.py
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| For example, on Armv7-M microcontrollers it can be useful to spill | ||
| from the GPR file to the FPR file. | ||
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| The type of this configuration option is architecture dependent. |
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I forgot the details here... are we always expecting this to be a dictionary of named values to be passed to the members of the Spill class?
If so, we could at least modify the getter to return {} if self._spill_type is None, removing the need for the if .. else below.
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If I'm not mistaken, the dictionary that is passed here is supposed to be the **kwargs in the Spill class in the arch model.
In one example we set slothy.config.constraints.spill_type = { 'spill_to_vreg': 24 }, which defines the starting point of the FPRs to spill to as an integer. So yes, having a dictionary here makes sense.
Thus, I think the solution of returning {} if self._spill_type is None, which will pass no key word argument spill_to_vreg to Spill.spill(), and therefore cause a spill to the stack instead of the FPR is fine.
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Can you document that we need a dict here?
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Done 👍 It's not super precise as the option itself leaves lots of freedom in the arch model. But I think it's clearer than before.
Previously, SLOTHY would fail when a global input was spilled via an instruction annotated with `// @slothy:is_spill`. This commit fixes this by ad-hoc creating a VirtualInstruction node for the input in this case -- as is done during ordinary DFG parsing already.
Commits extracted from
armv7mbranch as the example for the 769 Dilithium NTT breaks without this.