[PATCH] D66079: [SimplifyLibCalls] Add dereferenceable bytes from known callsites [WIP]

[Dávid Bolvanský via Phabricator via llvm-commits]

xbolva00 marked an inline comment as done.
xbolva00 added inline comments.


================
Comment at: lib/Transforms/Utils/SimplifyLibCalls.cpp:983
+  if (isIntrinsic)
+    return nullptr;
+
----------------
jdoerfert wrote:
> xbolva00 wrote:
> > jdoerfert wrote:
> > > What does the return value here mean? I'm also confused by the `Op0` which was there already.
> > > 
> > nullptr means that nothing was simplified.
> > 
> > below, for memcpy, we can just turn memcpy libcall to memcpy intrinsic.
> but why is the pointer operand returned?
llvm memcpy intrinsic "returns" void so in order to fix return value, we return dst pointer.

return memcpy(dst, ...)

to

llvm.memcpy(dst, ....)
return dst;

I dont know why this was designed this way :)


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  https://reviews.llvm.org/D66079/new/

https://reviews.llvm.org/D66079