similar to: [LLVMdev] illegal code generated for special architecture

Here is a last example to illustrate my concern. The problem is about the lowering of node t13. Initial selection DAG: BB#0 '_start:entry' SelectionDAG has 44 nodes: t11: i16 = Constant<0> t0: ch = EntryToken t3: ch = llvm.clp.set.rspa t0, TargetConstant:i16<392>, Constant:i32<64> t5: ch = llvm.clp.set.rspb t3,

The DAG dumping will try to print some of the nodes "inline" (i.e. where they are used) to make the output more readable, so the dump of the DAG may not strictly reflect the node ordering. -Krzysztof On 5/4/2018 8:18 AM, Dominique Torette via llvm-dev wrote: > Here is a last example to illustrate my concern. > > The problem is about the lowering of node t13. > >

Krzysztof, Thanks for your interest to my questions. In order to clarify the context, here is the C source file of my test case. The 3 builtins initialize some stack pointers. They have to be executed before any other instruction. extern float fdivfaddfmul_a(float a, float b, float c, float d); volatile static float x1,x2,x3,x4; void _start(void) { float res;

I'm trying to figure out how to interpret DAG output that is shown below. If I were to draw it by hand, how would I do it? I tried to do it, but unfortunately I can't figure it out. I know there is a way to generate a graph, but I made some changes to my backend which hangs clang/llc. Would someone be kind enough to give a picture of what of a graph below? I'm sure once I see one I

Hi llvm-dev, >> The CopyFromReg->CopyToReg->CopyFromReg sequence doesn’t have the chains set correctly: the second CopyFromReg’s input chain isn’t connected to the CopyToReg’s output chain. (This appears to be the same problem in both graphs.) The DAG mentioned was generated by the SelectionDAGBuilder and as much as possible, we only modify the files within our target so I tried

Evan Cheng wrote: > > On Dec 3, 2007, at 12:53 PM, Vladimir Prus wrote: > >> >> Suppose I have a target that does not have register+constant >> addressing mode. Then, I have DAG like: >> >> (store ..., (frameindex)) >> >> Targets like SPARC have the following patterns to catch this: >> >> def ADDRri : ComplexPattern<i32, 2,

Hello. After "Initial selection DAG" stage I get a DAG with node t14: ch = store<(store 4 into %ir.p45, align 8, addrspace 1)> t10, FrameIndex:i32<2>, FrameIndex:i32<3>, undef:i32 1. Where does it come from? Can I do anything to make it not appear? 2. If not, how do I change it so that the operand being stored would be first loaded into a register, and that register

I'm working on the code to handle GC tracing of "intermediate values" (as described in the GC doc), and I've run into a weird problem. (Note, this has nothing to do with the patch I have proposed, this error occurs with regular old pointer-allocas.) The exception I am getting occurs in this code here in SelectionDAGBuilder.cpp: *case* *Intrinsic*::gcroot: *if* (GFI) {

Hi, I'd like to understand how register allocation works in the case where an instruction is folded into another one. Where in the code would be a good place to start looking at? After ISEL, one of the instructions has another instruction folded into it, which looks like this t1: i32,i1,i1,i1,i1 = ADDRR TargetFrameIndex:i32<0>, MOVRI:i32,i1,i1 But during the 'Assembly

Hi, Is there a kind of scope mechanism in the instruction lowering pattern language in order to control where instructions are inserted or how they are later reordered during the SelectionDiag linearization? I know the glue chain that stick instructions together. But such mechanism in not provided in instruction lowering pattern. I'm facing many situations where some patterns are lowered into

Hi Talin, I think that the framework for GC assumes llvm.gcroot to be in the first block. If it is not the case in your example, it will break these assumptions. Nicolas On Sun, Sep 26, 2010 at 1:38 AM, Talin <viridia at gmail.com> wrote: > I'm working on the code to handle GC tracing of "intermediate values" (as > described in the GC doc), and I've run into a

Hi Tim, >That C++ function is probably what looks for an FrameIndex node and >has been taught that it can be folded into the load. How do you teach a function that a node can be folded into an instruction? ________________________________ From: Tim Northover <t.p.northover at gmail.com> Sent: Monday, January 21, 2019 11:52 PM To: Josh Sharp Cc: via llvm-dev Subject: Re: [llvm-dev]

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

I'm investigating a bug associated with debug information that manifests itself in the XCore backend (PR11105). I'd like to understand what the expected behavior of eliminateFrameIndex() is when it is called on a dbg_value machine instruction. Currently the XCore target replaces the frame index with the frame register and sets the next operand to the byte offset from the frame

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");

Hi Richard, Thanks for working on this! Your patched solved my initial problem, but introduced another one. Please find attached another BC file that fails on xcore with the linear scan regalloc. This is the error message I get eliminateFrameIndex Frame size too big: -3 0 llc 0x08affd1e 1 libc.so.6 0xb7d35a01 abort + 257 2 llc 0x081a0972

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'm trying to optimize the 'extract_vector_elt' for my SIMD microcontroller. The idea is, during DAG combination, to merge load/extract sequence into an architecture specific node. During Instruction Selection, this specific node will be target selected to an architecture specific instruction. By 'combination of DAG nodes' I understand 'replacing a set of DAG nodes by

On Mon, Jun 24, 2019 at 4:08 PM Tim Northover <t.p.northover at gmail.com> wrote: > On Mon, 24 Jun 2019 at 12:16, Gleb Popov via llvm-dev > <llvm-dev at lists.llvm.org> wrote: > > 1. Where does it come from? Can I do anything to make it not appear? > > It comes from something like: > > %ptr = alloca i8 > %var = alloca i8* > store i8* %ptr, i8**

I'm confused as to the logic used in the register scavenger when it cannot find a free register. I would think that it would want to free up the emergency spill slot immediately after it's use, because otherwise there is a chance of needing to use the emergency slot again and not be able to. Instead it tries to restore it only right before register it is freeing up. Maybe I'm