[llvm-commits] [llvm] r97797 - in /llvm/trunk: lib/Target/X86/X86ISelLowering.cpp test/CodeGen/X86/tailcall2.ll

[Evan Cheng]

On Mar 5, 2010, at 2:18 AM, Duncan Sands wrote:

> Hi Evan,
> 
>> Fix an oops in x86 sibcall optimization. If the ByVal callee argument is itself passed as a pointer, then it's obviously not safe to do a tail call.
> 
>> +      // define @foo(%struct.X* %A) {
>> +      //   tail call @bar(%struct.X* byval %A)
>> +      // }
> 
> in this case maybe the call should not have been marked "tailcall" in the
> first place?  i.e. I'm suggesting that this is really a bug in
> TailRecursionElimination.

My understanding is it is correct. I find "tailcall" marker extremely confusing, but it's what we have for now.

Evan

> 
>> +      // ByVal argument is passed in as a pointer but it's now being
>> +      // derefernced. e.g.
> 
> derefernced -> dereferenced
> 
> Ciao,
> 
> Duncan.
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