Remove unecessary empty asm statement

[hughbe]

@jckarter 5 days ago Member
@rjmccall or @gparker42, do either of you recall why this is here? If it were intended as an optimization barrier, wouldn't it have to be volatile? As is, this would be a no-op even on Clang, AIUI.

@gparker42 3 days ago
The intent is to preserve that frame in stack traces. I know the asm("") is necessary when the function is empty. This function is not empty so noinline alone may be sufficient.

@gparker42 days ago Member
(> If the function is empty and you use noinline without asm("") then the optimizer may simply delete the call at the call site. Technically that doesn't count as inlining. asm("") inhibits that optimization.)

Extracted from #7765 as don't have time right now to test my fixes, and Cambodian internet is too slow to update LLVM from git..

[hughbe]

@swift-ci please smoke test

[hughbe]

Friendly ping :)

[jckarter]

LGTM. Did you verify empirically that the cast failure is visible in a backtrace from a release build of the runtime?

[hughbe]

Sorry @joegroff I don't understand what you mean - do you mean the generate assembly?

https://godbolt.org/g/czYXiV shows that assembly is the same for a noinline method with and without asm("") that has at least one method call in it

[jckarter]

That's what I meant. Thanks for checking.