similar to: [LLVMdev] About trapvalues

Thank you for your reply! > Every MachineBasicBlock has a list of successors; you can access it with > the successors() accessor. That's what you should be using for any CFG > analysis. I am aware of these methods of class MachineBasicBlock, which allows one to access a MachineBasicBlock's successors and predecessors in the CFG. But the CFG itself may no longer be valid if a

Hi Devang, Thanks for your reply. But if you look at the comment of BasicBlock::splitBasicBlock(), it says that "...an unconditional branch is added to the new BB, and the rest of the instructions in the BB are moved to the newBB, including the old terminator." So, the terminator of the newBB is exactly the same as the terminator of the oldBB. IF the oldBB has multiple successors,

Hi, Is changing the successors for each basic blocks means by default that the Terminator Instruction will be changed or this is another problem should be solved? If case 2 please tell me how to change it according to the new successors? Thanks -- * Rasha Salah Omar Msc Student at E-JUST Demonestrator at Faculty of Computers and Informatics Benha University* * e-mail:

Hi, there! There are situations where a machine basic block has to be split into two machine basic blocks, e.g., to place a constant pool entry or to fix a conditional branch so that its target is within its range (https://reviews.llvm.org/D38918). However, it doesn't appear to be straightforward how the control flow graph should be updated when a machine basic block is split,

Hi Rasha, > Is changing the successors for each basic blocks means by default that the > Terminator Instruction will be changed or this is another problem should be > solved? I think the only way you *can* change a basic block's successors is by changing its terminator instruction, so "by default" is the closest answer. Though you should make sure your basic block only has

> The right way to update the CFG very much depends on how you're > transforming it. I would like to export the CFG for control flow checking. Theoretically, it should be possible for a compiler to know every target of every control flow instruction, except for computed targets that are not known at compile-time. When a machine basic block is split between two branches, as shown below:

On Jun 7, 2012, at 7:31 PM, Hal Finkel wrote: > 112B BB#1: derived from LLVM BB %for.body, ADDRESS TAKEN > Predecessors according to CFG: BB#0 BB#1 > %vreg12<def> = PHI %vreg13, <BB#1>, %vreg11, <BB#0>;CTRRC8:%vreg12,%vreg13,%vreg11 > %vreg13<def> = COPY %vreg12<kill>; CTRRC8:%vreg13,%vreg12 > %vreg13<def> = BDNZ8 %vreg13,

Under what circumstances will a TerminatorInst will have multiple successors? The three methods: virtual BasicBlock *getSuccessorV(unsigned idx) const = 0; virtual unsigned getNumSuccessorsV() const = 0; virtual void setSuccessorV(unsigned idx, BasicBlock *B) = 0; are defined for the TerminatorInst class, but I cannot see why a terminator is allowed to go to different targets. Thanks,

I've been out of the loop for awhile. Is there an email thread about the "removing terminators as a thing" concept? On Wed, Oct 31, 2018, 10:13 PM Chris Lattner via llvm-dev < llvm-dev at lists.llvm.org wrote: > FWIW, I’m generally supporting of this direction, and would love to see > asm goto support. > > Could you compare and contrast asmbr to a couple other

+1, sounds like a great idea And if you're volunteering to do the work, even better! :) Philip p.s. Any reason we can't preserve a TerminatorInst type with an isa function which just returns true for all our terminators but without having terminators actually inherit from it?  If so, we preserve the bit of a "type safety" for a variable which is expected to always point to

Hi All, I need to remove successors from every basic block to insert new ones I tried this code, but it doesn't work void RemoveSuccessor(TerminatorInst *TI, unsigned SuccNum) { assert(SuccNum < TI->getNumSuccessors() && "Trying to remove a nonexistant successor!"); // If our old successor block contains any PHI nodes, remove the entry in the //

(and FWIW, I'm currently trying to finish the patch that makes this a reality... mostly hard because it has to unwind a loooot of complexity we've built up due to not having this) On Sat, Nov 3, 2018 at 5:47 PM Jeremy Lakeman via llvm-dev < llvm-dev at lists.llvm.org> wrote: > http://lists.llvm.org/pipermail/llvm-dev/2018-May/123407.html > > TLDR; CallInst & InvokeInst

Hi Dean, Thanks for your reply. That's exactly what I am doing, but I was looking for a default optimization or pass implementation if there was. I used BasicBlock::splitBasicBlock() but it puts "br" end of original basic block. I tried to delete the br instruction by using eraseFromParent() but it didn't work. I had to rewrite my own splitBasicBlock() by modifying the

...this is moving from llvm-commits to llvm-dev. On Feb 10, 2012, at 12:14 PM, Sergei Larin <slarin at codeaurora.org> wrote: > 1) Can a BB presented to the MI scheduler be _not_ terminated (end on a non > terminator MI) under any circumstances? Below you are speaking about "Empty > blocks, or blocks with only a single instruction that not a terminator..." - > What

> On May 17, 2018, at 2:03 AM, Chandler Carruth via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > Going to keep this RFC short and to the point: > > TerminatorInst doesn't pull its weight in the type system. There is essentially a single relevant API -- iterating successors. There is no other interesting aspect shared -- the interface itself just dispatches to

On Fri, May 18, 2018 at 10:26 PM Chris Lattner via llvm-dev < llvm-dev at lists.llvm.org> wrote: > > > > On May 17, 2018, at 2:03 AM, Chandler Carruth via llvm-dev < > llvm-dev at lists.llvm.org> wrote: > > > > Going to keep this RFC short and to the point: > > > > TerminatorInst doesn't pull its weight in the type system. There is >

Going to keep this RFC short and to the point: TerminatorInst doesn't pull its weight in the type system. There is essentially a single relevant API -- iterating successors. There is no other interesting aspect shared -- the interface itself just dispatches to specific instructions to be implemented. On the flip side, CallInst and InvokeInst have *massive* amounts of code shared and struggle

I used successors to find the basic blocks that can be visited and those that cannot be reached. My pass just prints out those blocks which can be reached. The problem is that I want to include this in my compiler code rather than as a separate .cpp file which will perform the pass when I use 'opt'. I have seen that there is something called a PassManager class. Will this help me any way ?

Hello again, I am trying to implement an optimization pass for PowerPC such that simple loops use the special "counter register" (CTR) to track the induction variable. This is helpful because, in addition to reducing register pressure, there is a combined decrement-compare-and-branch instruction BZND (there are also other related instructions). I started this process by converting the

On Oct 15, 2008, at 11:38 AMPDT, Daniel M Gessel wrote: > I'm analyzing the basic blocks of MachineInstructions that LLVM > generates for my TargetMachine to try to reconstruct high-level flow > control. > > I misunderstood the isTerminator property of an instruction to mean > that it had to be at the end of a basic block, but now I've seen > blocks that end with a