ZJIT: Get type information from branchif, branchunless, branchnil instructions (#15915)HEADmaster

Do a sort of "partial static single information (SSI)" form that learns
types of operands from branch instructions. A branchif, for example,
tells us that in the truthy path, we know the operand is not nil, and
not false. Similarly, in the falsy path, we know the operand is either
nil or false.

Add a RefineType instruction to attach this information.

This PR does this in SSA construction because it's pretty
straightforward, but we can also do a more aggressive version of this
that can learn information about e.g. int ranges from other checks later
in the optimization pipeline.

0 files changed, 0 insertions, 0 deletions