bors f4555ef5e1 Auto merge of #111752 - dingxiangfei2009:lower-or-pattern, r=cjgillot
Lower `Or` pattern without allocating place

cc `@azizghuloum` `@cjgillot`

Related to #111583 and #111644

While reviewing #111644, it occurs to me that while we directly lower conjunctive predicates, which are connected with `&&`, into the desirable control flow, today we don't directly lower the disjunctive predicates, which are connected with `||`, in the similar fashion. Instead, we allocate a place for the boolean temporary to hold the result of evaluating the `||` expression.

Usually I would expect optimization at later stages to "inline" the evaluation of boolean predicates into simple CFG, but #111583 is an example where `&&` is failing to be optimized away and the assembly shows that both the expensive operands are evaluated. Therefore, I would like to make a small change to make the CFG a bit more straight-forward without invoking the `as_temp` machinery, and plus avoid allocating the place to hold the boolean result as well.
2023-09-01 10:54:56 +00:00
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