Make br_if return the value of its value operand. #539
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This follows naturally from br_if's value operand being strict. We evaluate the expression to produce a value even when the condition is false, so it'd be nice to be able to use the value when the condition is false too. This change also makes sense from a low-level compiler perspective. The value operand of a br_if represents a value "live out" of the br_if's basic block. Since br_if is a simple conditional branch, the value should be "live in" in both succesors.
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WebAssembly/spec#237 is a PR to the spec repo implementing this, which has the specific proposal for how to do the type checking. |
ghost
mentioned this pull request
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Closing, as the spec PR is now closed. |
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This follows naturally from br_if's value operand being strict. We
evaluate the expression to produce a value even when the condition is
false, so it'd be nice to be able to use the value when the condition
is false too.
This change also makes sense from a low-level compiler perspective. The
value operand of a br_if represents a value "live out" of the br_if's
basic block. Since br_if is a simple conditional branch, the value
should be "live in" in both succesors.