| So why are Hoopl's rewrite functions specialized to UniqSM monad? My
| understanding so far was that this is precisely because we need access to
Uniq
| supply to generate new labels and registers during rewriting. I'm guessing
that
| nobody intended that these newly generated things will be added as facts?
Correct.
| complicated_expr, I rewrite a store to a stack location with
|
| newReg1 = complicated_expr
| I32[(old + 4)] = newReg1
Yes, as Simon says, you need a deterministic name for newReg1. An obvious
choice would be
reg_L3_7
if this was the 7th instruction of a block whose label was L3. Then the
register name would be unaffected by any other rewrites, in any other block, or
earlier in this block.
But that's not altogether easy, since LocalRegs are identified by a Unique, not
a string.
One possibility is to do this transformation once and for all, *before* the
constant-prop pass, since it is not dependent on the facts generated by the
pass.
Simon
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