[PATCH] D37093: [coroutines] Promote cleanup.dest.slot-like allocas to registers to avoid storing them in the coroutine frame

[Gor Nishanov via Phabricator via llvm-commits]

GorNishanov marked an inline comment as done.
GorNishanov added inline comments.


================
Comment at: lib/Transforms/Coroutines/CoroFrame.cpp:789
+  // the entry node.
+  for (BasicBlock::iterator I = BB.begin(), E = --BB.end(); I != E; ++I)
+    if (auto *AI = dyn_cast<AllocaInst>(I))
----------------
eric_niebler wrote:
> Knowing nothing about how this code works, it seems strange to me that you are ignoring the last instruction in the basic block, but the comment says you're looking at all instructions.
Block should always end in a terminator instruction. AllocaInst is not a terminator, hence, no need to check for it. Here is another place with a similar loop (from where it was shamelessly stolen from :-))


```
C:\GitHub\llvm\lib\Transforms\Utils\Mem2Reg.cpp:
   39      // Find allocas that are safe to promote, by looking at all instructions in
   40      // the entry node
   41:     for (BasicBlock::iterator I = BB.begin(), E = --BB.end(); I != E; ++I)
   42        if (AllocaInst *AI = dyn_cast<AllocaInst>(I)) // Is it an alloca?
   43          if (isAllocaPromotable(AI))
```


https://reviews.llvm.org/D37093