[Codegen] Do not emit br instructions if the insertion point is null
#5
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When a block contains a `return` statement, we should not add another `br` instruction at its end, as it's already terminated. This was previously achieved by setting the insertion point to null when encountering a `ResolvedReturnStmt`. Unfortunately, this "orphan" `br` is still considered a predecessor of the target basic block (which is shown by `preds = <null operand!>` in the IR). If using a debug build of LLVM, this triggers a "Uses remain when a value is destroyed!" assertion in `~BasicBlock`, as the `br` is never destroyed.
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Thank you for catching this! I would have a few suggestions for the implementation though in #6. Please let me know what you think about them. |
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When a block contains a
returnstatement, we should not add anotherbrinstruction at its end, as it's already terminated. This was previously achieved by setting the insertion point to null when encountering aResolvedReturnStmt.Unfortunately, this "orphan"
bris still considered a predecessor of the target basic block (which is shown bypreds = <null operand!>in the IR). If using a debug build of LLVM, this triggers a "Uses remain when a value is destroyed!" assertion in~BasicBlock, as thebris never destroyed.