[PATCH] D82314: [RFC][Coroutines] Optimize the lifespan of temporary co_await object

[JunMa via Phabricator via cfe-commits]

junparser added a comment.

In D82314#2109437 <https://reviews.llvm.org/D82314#2109437>, @lxfind wrote:

> In D82314#2107910 <https://reviews.llvm.org/D82314#2107910>, @junparser wrote:
>
> > Rather than doing it here, can we build await_resume call expression with MaterializedTemporaryExpr when expand the coawait expression. That's how gcc does.
>
>
> There doesn't appear to be a way to do that in Clang. It goes from the AST to IR directly, and there needs to be a MaterializedTemporaryExpr to wrap the result of co_await. Could you elaborate on how this might be done in Clang?


For now, we only wrap coawait expression with MaterializedTemporaryExpr when the kind of result is VK_RValue, We can wrap await_resume call instead in such case when build coawait expression. so in emitSuspendExpression, we can directly emit await_call expression with MaterializedTemporaryExpr.

I think this should work, although i'm not so sure.


Repository:
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