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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Correction:</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>The analysis I made regarding the callers
knowledge of sign/zero extension of return value is flawed. So I take it back. </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Never the less, I don’t see how adding
attributes would resolve this problem either. </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Ali</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
llvmdev-bounces@cs.uiuc.edu [mailto:llvmdev-bounces@cs.uiuc.edu] <b><span
style='font-weight:bold'>On Behalf Of </span></b>Alireza.Moshtaghi@microchip.com<br>
<b><span style='font-weight:bold'>Sent:</span></b> Sunday, May 18, 2008 6:33 PM<br>
<b><span style='font-weight:bold'>To:</span></b> llvmdev@cs.uiuc.edu<br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [LLVMdev] Troubling
promotion of return value to Integer ...</span></font></p>
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12.0pt'> </span></font></p>
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<p class=MsoNormal><font size=3 color=navy face="Times New Roman"><span
style='font-size:12.0pt;color:navy'>But they both follow the same calling
convention. There are two possibilities in the caller:</span></font></p>
<p class=MsoNormal><font size=3 color=navy face="Times New Roman"><span
style='font-size:12.0pt;color:navy'>1) Call node returns sizeof(int) or larger:
in this case there is no truncation.</span></font></p>
<p class=MsoNormal><font size=3 color=navy face="Times New Roman"><span
style='font-size:12.0pt;color:navy'>2) Call node returns smaller than
sizeof(int): in this case callee always has to return an int so it has to
consistently either sign extend or zero extend because int is either signed or
unsigned consistently for that port. Assuming that caller and callee follow the
same calling convention, caller always knows (hence the llvm pass knows) that,
if the return value of the called function is being truncated, it is because of
return value promotion. It also knows the calling convention, so it knows whether
it is sign or zero extended. This is regardless of translation unit where the
callee is in.</span></font></p>
<p class=MsoNormal><font size=3 color=navy face="Times New Roman"><span
style='font-size:12.0pt;color:navy'> </span></font></p>
<p class=MsoNormal><font size=3 color=navy face="Times New Roman"><span
style='font-size:12.0pt;color:navy'>></span></font>No, because the callee
and caller may be in different translation units.</p>
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