[PATCH] D140166: [IR] return nullptr in Instruction::getInsertionPointAfterDef for CallBrInst

[Nikita Popov via Phabricator via llvm-commits]

nikic added inline comments.


================
Comment at: llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp:3381-3383
+  // CallBr's don't have a single point after a def to insert at.
+  if (isa<CallBrInst>(Call))
+    return false;
----------------
StephenTozer wrote:
> This might be more aggressive than necessary, since if the return type doesn't change or the call instruction has no use, a PHI does not need to be inserted; this could be moderated by moving this to the block at line 3409 (`if (OldRetTy != NewRetTy)`), and checking whether the return value has any uses. With that said, this is a minor point since as you said this won't even be touched at this point, so doesn't need to block merging imo.
This entire transform is not relevant for callbr, it only works on calls to functions, not calls to inline asm. You could replace this with `assert(!isa<CallBrInst>(Call))`.


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  https://reviews.llvm.org/D140166/new/

https://reviews.llvm.org/D140166