search for: requiresframeindexscaveng

Hello all, For my custom processor backend I am trying add some instruction using BuildMI() inside eliminateFrameIndex(). I tried RegScavenger like this: unsigned RegUnused0 = RS->FindUnusedReg(&LASER::GNPRegsRegClass); if (!RegUnused0) RegUnused0 = RS->scavengeRegister(&LASER::GNPRegsRegClass, II, SPAdj); assert(RegUnused0 && "Register scavenger failed");

I need to use ‘createVirtualRegister’ for a specific case in my ‘eliminateFrameIndex’ function implementation. However, whenever that code is executed, I get the assertion "MachineCopyPropagation should be run after register allocation!” at a later stage. I have seen that at least a couple of backend implementations (including ARM Thumb) create virtual registers in ‘eliminatedFrameIndex’.

Hi! I started writing a LLVM backend for a custom architecture. I have some register and instruction .td files and some other files/classes like a MCStreamer for assembler output. At the moment I can compile some empty programs so far. I implemented the method ::eliminateFrameIndex() similar to the Sparc and ARM backend. The method looks like this: // frame pointer is in reg of class

Thanks Jon and Hal for the helpful pointers. By returning true from requiresRegisterScavenging() and requiresFrameIndexScavenging(), LLVM handled all the scavenging effort. That is nearly painless for the target, so why do some targets seem to do scavenging on their own? When the scavenged register is loaded with a simple immediate, is it safe to search the BB and replace other uses of the same immediate with the reg? I...

On 1/29/15 2:00 PM, Steve King wrote: > Hello LLVM, > The ARM target sometimes adds an instruction with a virtual register > in eliminateFrameIndex(): > > https://github.com/llvm-mirror/llvm/blob/master/lib/Target/ARM/ARMBaseRegisterInfo.cpp > > This looks late for a virtual register to appear. Where is this vreg made real? The register scavenger should take care of such

...To: jonathan at codesourcery.com > Cc: llvmdev at cs.uiuc.edu > Sent: Friday, January 30, 2015 10:52:19 AM > Subject: Re: [LLVMdev] creating a vreg in eliminateFrameIndex() > > Thanks Jon and Hal for the helpful pointers. By returning true from > requiresRegisterScavenging() and requiresFrameIndexScavenging(), LLVM > handled all the scavenging effort. That is nearly painless for the > target, so why do some targets seem to do scavenging on their own? Some of the targets pre-date the introduction of that feature. > > When the scavenged register is loaded with a simple immediate, is i...

Hello LLVM, The ARM target sometimes adds an instruction with a virtual register in eliminateFrameIndex(): https://github.com/llvm-mirror/llvm/blob/master/lib/Target/ARM/ARMBaseRegisterInfo.cpp This looks late for a virtual register to appear. Where is this vreg made real? Thanks, -steve