SILOptimizer: fix a stack nesting problem when inlining coroutines #22285
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eeckstein
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rjmccall
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| /// | ||
| /// In this case stack nesting must be corrected after inlining with the | ||
| /// StackNesting utility. | ||
| static bool needUpdateStackNesting(FullApplySite apply) { |
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Usually predicates are written in the third-person singular present, so I think this should be needsUpdateStackNesting.
Beside fixing the compiler crash, this change also improves the stack-nesting correction mechanisms in the inliners: * Instead of trying to correct the nesting after each inlining of a callee, correct the nesting once when inlining is finished for a caller function. This fixes a potential compile time problem, because StackNesting iterates over the whole function. In worst case this can lead to quadratic behavior in case many begin_apply instructions with overlapping stack locations are inlined. * Because we are doing it only once for a caller, we can remove the complex logic for checking if it is necessary. We can just do it unconditionally in case any coroutine gets inlined. The inliners iterate over all instruction of a function anyway, so this does not increase the computational complexity (StackNesting is roughly linear with the number of instructions). rdar://problem/47615442
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Beside fixing the compiler crash, this change also improves the stack-nesting correction mechanisms in the inliners:
Instead of trying to correct the nesting after each inlining of a callee, correct the nesting once when inlining is finished for a caller function.
This fixes a potential compile time problem, because StackNesting iterates over the whole function.
In worst case this can lead to quadratic behavior in case many begin_apply instructions with overlapping stack locations are inlined.
Because we are doing it only once for a caller, we can remove the complex logic for checking if it is necessary.
We can just do it unconditionally in case any coroutine gets inlined.
The inliners iterate over all instruction of a function anyway, so this does not increase the computational complexity (StackNesting is roughly linear with the number of instructions).
rdar://problem/47615442