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David,</div>
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It is done inside eliminateFrameIndex(). I'm trying to move the stack offset to a register by using my custom MOVRI_P pseudo instruction this way:<br>
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unsigned AR = MF.getRegInfo().createVirtualRegister(XXX::RegClass);</div>
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<span></span>BuildMI(MB,II,dl, TII.get(XXX::MOVRI_P), AR).addImm(Offset);</div>
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(When I print AR, I get 2147483648 = 0x80000000)<br>
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Then, in expandPostRAPseudo(), I replace it with the real MOVRI instruction</div>
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<span>MachineOperand op_0 = MI.getOperand(0);<br>
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<div>MachineOperand op_1 = MI.getOperand(1);<br>
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<div>BuildMI(MB,MBI,dl, get(XXX::MOVRI)).add(op_0).add(op_1);<br>
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At this point op_1_0.getReg() is 2147483648 and op_1_1.getImm() is correct<br>
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When I execute the program it says: <span>Assertion `RegNo && RegNo < 37 && "Invalid register number!"' failed.<br>
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<div>Thanks<br>
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<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt" face="Calibri, sans-serif" color="#000000"><b>From:</b> David Greene <dag@cray.com><br>
<b>Sent:</b> Monday, February 18, 2019 5:22 PM<br>
<b>To:</b> Josh Sharp<br>
<b>Cc:</b> via llvm-dev<br>
<b>Subject:</b> Re: [llvm-dev] New to LLVM. Need help getting available register</font>
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<div class="PlainText">It would help if you can describe in more detail what you are trying to do.<br>
In which phase of the compiler is this being done? What is your ultimate<br>
goal?<br>
<br>
I would not look to unit tests as good examples of how to do things. They<br>
are specifically designed to pinpoint small bits of functionality and often<br>
rare corner cases. It's possible the bit of code you're looking at is actually<br>
testing that the assertion triggers.<br>
<br>
-David<br>
<br>
________________________________________<br>
From: Josh Sharp <mm92126@hotmail.com><br>
Sent: Saturday, February 16, 2019 8:38:53 PM<br>
To: David Greene<br>
Cc: via llvm-dev<br>
Subject: Re: [llvm-dev] New to LLVM. Need help getting available register<br>
<br>
Is it possible to get a virtual register and then use that to create a real register? I've seen it done in unittests/CodeGen/MachineInstrTest.cpp like this:<br>
<br>
unsigned VirtualDef1 = -42;<br>
VD1VU->addOperand(*MF,<br>
MachineOperand::CreateReg(VirtualDef1, /*isDef*/ true));<br>
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<br>
But when I do that in my code I get an assertion so I wasn't sure if it's legal or not.<br>
Thanks.<br>
<br>
________________________________<br>
From: David Greene <dag@cray.com><br>
Sent: Wednesday, January 2, 2019 9:23 AM<br>
To: m m<br>
Cc: via llvm-dev<br>
Subject: Re: [llvm-dev] New to LLVM. Need help getting available register<br>
<br>
m m via llvm-dev <llvm-dev@lists.llvm.org> writes:<br>
<br>
> I'm new to LLVM. I'd like to know if there is a method I can call<br>
> whenever I need any available CPU register.<br>
<br>
Take a look at RegisterScavenging. Of course, this only works after<br>
register allocation. Before register allocation you'd just create a new<br>
virtual register.<br>
<br>
-David<br>
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