similar to: [LLVMdev] Classifying Operands & Def/Use Chains

On Jan 11, 2008, at 2:00 PM, David Greene wrote: > Is there any way to discover whether a particular operand of a > MachineInst > participates in addressing? That is, if the MachineInst references > memory, > can I tell, given an operand, whether that operand is part of the > address > calculation for the instruction? Nope, not that I know of. > Also, is there any

On Friday 11 January 2008 16:36, Chris Lattner wrote: > On Jan 11, 2008, at 2:00 PM, David Greene wrote: > > Is there any way to discover whether a particular operand of a > > MachineInst > > participates in addressing? That is, if the MachineInst references > > memory, > > can I tell, given an operand, whether that operand is part of the > > address >

Is LiveVariables updated correctly when TII->RemoveBranch and TII->InsertBranch are called in the following piece of code? - MachineBasicBlock::updateTerminator() line 307 of MachineBasicBlock.cpp: if (FBB) { // The block has a non-fallthrough conditional branch. If one of its // successors is its layout successor, rewrite it to a fallthrough // conditional branch.

On May 2, 2011, at 3:51 PM, Akira Hatanaka wrote: > - vreg81's VarInfo: > Alive in blocks: 5, 6, 7, 8, 10, 12, 13, 19, > Killed by: > #0: J <BB#17> > > > As you can see, VarInfo vreg81 is killed by the unconditional jump instruction of BB#20 when it should be killed by the newly created conditional branch in BB#14 (BEQ). Is this a bug in

On 08/09/05, Alkis Evlogimenos <evlogimenos at gmail.com> wrote: > to those coalesced registers, it is logical that noone will ever query > the liveness of those registers (unless there is a bug somewhere in the Indeed the coalesced registers may logically not be queried since they do not appear in any operand list of the machine code, but the VarInfo::DefInst in VirtRegInfo of the

I though LiveVariables may be invalidated by LiveIntervals, but it's declared not: void LiveIntervals::getAnalysisUsage(AnalysisUsage &AU) const { AU.addPreserved<LiveVariables>(); AU.addRequired<LiveVariables>(); ... LiveInterval may coalesce virtual registers and remove identity moves instructions: bool LiveIntervals::runOnMachineFunction(MachineFunction &fn) {

On Wed, 2005-09-07 at 18:24 +0800, Tzu-Chien Chiu wrote: > I though LiveVariables may be invalidated by LiveIntervals, but it's > declared not: > > void LiveIntervals::getAnalysisUsage(AnalysisUsage &AU) const > { > AU.addPreserved<LiveVariables>(); > AU.addRequired<LiveVariables>(); > ... > > LiveInterval may coalesce virtual registers and

I'm writing a peephole pass and I'm done with the X86_64 instruction level detail work. But I'm having difficulty with the basic block surgery of replacing the old MachineInst. The peephole pass gets called per MachineFunction and then iterates over each MachineBasicBlock and in turn over each MachineInst. When it finds an instruction which should be replaced, it builds a new

Ok, i'm having a problem with understanding the allocating of registers. I've written in the "addPassesToEmitAssembly()" the passes to create the assembly code, as in the PowerPC example. I'ved tried filling up as much of the code in <Target>RegisterInfo.cpp (Register/Frame code) to handle writing and reading from stack. The allocation method I used was

Hi folks, I would like to find out the machine instructions that use some given registers in the reverse order, and I came across these iterators (use_iterator/reg_iterator). However, there are two things I noticed: 1) These iterators seem to traverse the machine function a bit differently from what I get from the machine function dump. In other words, the use_iterator list is not constructed in

Thanks Quentin. I'm trying to examine from the operands of the return instruction, and then to get the last assignment of those. I thought use_iterator/reg_iterator may suit better than just loop through the machine basicblock in the reverse order. Cheng-Chih On Thu, Sep 25, 2014 at 1:51 PM, Quentin Colombet <qcolombet at apple.com> wrote: > Hi Cheng-Chih, > > On Sep 25,

On Mon, May 16, 2005 at 05:15:30PM -0700, John Cortes wrote: > If I use any of the regalloc parameters (local, ...) I get an error in > the LiveVariable.cpp file, in the part that I think cheaks for dead > code because a Variable didn't have a defined Instance to a Machine > instruction. > > " llc: LiveVariables.cpp:86: void >

Hello. I am new to R, so my question/problem might be very basic, but I cannot figure out how to solve it. So, I would really appreciate your help. I would like to rename a variable in a very large file (181GB) called "2013.xdf" that is saved on my external hard drive. I tried running the following code to rename variable # 2 in the file and save this change, which produced some

Hello, I recently found that LLVM generates sub-optimal assembly for a tail call optimization case. Below is an example (https://godbolt.org/z/ao15xE): > void g1(); > void g2(); > void f(bool v) { > if (v) { > g1(); > } else { > g2(); > } > } > The assembly generated is as follow: > f(bool): # @f(bool) > testb %dil, %dil > je .LBB0_2 >

One of my pass requires LiveIntervals to build the interference graph, because LiveVariables do not provide an interface to iterate through all viritual registers. But LiveIntervalAnalysis.h is not in "include/llvm/CodeGen", so I have to either include it by: #include "../../llvm/lib/CodeGen/LiveIntervalAnalysis.h" or point my project include path to

Hi, I need to find out all the places where the value of a variable is being used. For this I have to implement reaching definitions(def-use chains). When I searched for its implementation I found Iterating over def-use & use-def chains <http://llvm.org/docs/ProgrammersManual.html#iterate_chains>. will this work for finding the places where a variable is reaching? I tried to use

On Tue, 20 Sep 2005, Tzu-Chien Chiu wrote: > One of my pass requires LiveIntervals to build the interference graph, Ok. > because LiveVariables do not provide an interface to iterate through > all viritual registers. Ok, you could add a method to LiveVariables that returns VirtRegInfo.size(). The virtual registers are defined by the range: [MRegisterInfo::FirstVirtualRegister,

Does updateTerminator() need to be rewritten in order to implement the changes you suggested (call LV->replaceKillInstruction)? Or can it be taken care of just by adding code to the files in Target/Mips? Also, is the generated code still correct if -disable-phi-elim-edge-splitting is added to the command line options? On Mon, May 2, 2011 at 5:00 PM, Jakob Stoklund Olesen <stoklund at

On 20/09/05, Chris Lattner <sabre at nondot.org> wrote: > > because LiveVariables do not provide an interface to iterate through > > all viritual registers. > > Ok, you could add a method to LiveVariables that returns > VirtRegInfo.size(). The virtual registers are defined by the range: > [MRegisterInfo::FirstVirtualRegister, >

Hi Duncan Sands, I frankly don't know what a variable gets converted to (SSA register or memory chunk). What I meant is, for example I1: int i, j=10; I2: scanf("%d", &j); I3: i = j + 1; Here I want to know whether the value of j in I1 reaches I3 or not. Best Regards, Srikanth Vaindam you didn't define what you mean by a variable. LLVM has virtual registers which are