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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I’m still trying to track down some alignment issues
with loads(i.e. 8/16 bit loads being turned into 32bit sign extending loads)
and I cannot for the life of me seem to figure out how to enter this section of
code:<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 color=green
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:green'>// If this is an unaligned load and the target doesn't support it,<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'>
<font color=green><span style='color:green'>// expand it.<o:p></o:p></span></font></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'>
<font color=blue><span style='color:blue'>if</span></font>
(!TLI.allowsUnalignedMemoryAccesses()) {<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'>
<font color=blue><span style='color:blue'>unsigned</span></font> ABIAlignment =
TLI.getTargetData()-><o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'>
getABITypeAlignment(LD->getMemoryVT().getTypeForMVT());<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'>
<font color=blue><span style='color:blue'>if</span></font>
(LD->getAlignment() < ABIAlignment){<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'>
Result = ExpandUnalignedLoad(cast<LoadSDNode>(Result.getNode()), DAG,<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'>
TLI);<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'>
Tmp1 = Result.getOperand(0);<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'>
Tmp2 = Result.getOperand(1);<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'>
Tmp1 = LegalizeOp(Tmp1);<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'>
Tmp2 = LegalizeOp(Tmp2);<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'>
}<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'>
}<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'>This is from LegalizeDAG.cpp:2146<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'>The problem that I see is that LD->getAlignment()
is set via the call getMVTAlignment(VT) in SelectionDAG.cpp:3385, which in turn
calls TLI.getTargetData()->getABITypeAlignment(Ty).<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'>So, the statement if (LD->getALignment() <
ABIAlignment) always fails from what I can see. Even if I set in my DataLayout
that i8 should have a 32bit ABI alignment, this does not work because the load
alignment is set to the ABI alignment instead of being set based on the actual
bit size. </span></font><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Any hints would be greatly appreciated, this is a blocking
issue that I just cannot seem to resolve without modifying the LLVM codebase to
remove the extend + load -> extload combining step.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Micah Villmow<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Systems Engineer<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Advanced Technology & Performance<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Advanced Micro Devices Inc.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><ns13:Street w:insAuthor="Micah Villmow"
w:insDate="2009-02-18T09:59:00Z" w:endInsAuthor="Micah Villmow"
w:endInsDate="2009-02-18T09:59:00Z"><ns13:address w:insAuthor="Micah Villmow"
w:insDate="2009-02-18T09:59:00Z" w:endInsAuthor="Micah Villmow"
w:endInsDate="2009-02-18T09:59:00Z">S1-609 One AMD Place</ns13:address></ns13:Street></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><ns13:place w:insAuthor="Micah Villmow"
w:insDate="2009-02-18T09:59:00Z" w:endInsAuthor="Micah Villmow"
w:endInsDate="2009-02-18T09:59:00Z"><ns13:City w:insAuthor="Micah Villmow"
w:insDate="2009-02-18T09:59:00Z" w:endInsAuthor="Micah Villmow"
w:endInsDate="2009-02-18T09:59:00Z"><st1:City w:st="on"><st1:place w:st="on">Sunnyvale</st1:place></st1:City></ns13:City></ns13:place>,
CA. 94085</span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>P: 408-749-3966</span></font><o:p></o:p></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font><font size=2 face=Arial><span style='font-size:
10.0pt;font-family:Arial'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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