similar to: [LLVMdev] BR_CC questions

Hi everyone, I have the following code (as part of a larger function): %0 = icmp eq i16 %a, 0 ; <i1> [#uses=1] br i1 %0, label %bb1, label %bb I would like to match this with a BRCOND, but all I get is an error message when compiling the above code that say: LLVM ERROR: Cannot yet select: 0x170f200: ch = br_cc 0x170f000, 0x170ed00, 0x170dc60, 0x170ec00, 0x170ef00 [ID=19]

hi Eli, thanks for reply :) i am currently decompose the BR_CC node to a target SETCC node and a target BRCOND node, but since BR_CC node sometimes is combine from a BRCOND node and SETCC node, so i just wondering if theres any better way :) regards --ether

Hi Eli, Thanks again for your reply. I am unsure about implementing the getCrossCopyRegClass for my target. My target does not support or allow moves to and from the SR. The SR exists because it has implicit involvement in some instructions, but it is opaque to the assembler and to the user as a register. I mean, there are no instructions to directly move or read it, or even access it directly.

Hi Eli, Thank you very much for your response. In fact, I had already tried the X86 approach before, i.e explicitly using the status register. This is the approach that appeals more to me. I left it parked because it also produced some problems (but I left it commented out). So I have now re-lived the code, and it works fine in most cases, but there’s a particular case that causes LLVM to stop

On Tue, Mar 15, 2016 at 2:21 PM, Krzysztof Parzyszek via llvm-dev < llvm-dev at lists.llvm.org> wrote: > On 3/15/2016 4:16 PM, Rail Shafigulin via llvm-dev wrote: > >> Below is the output of llc with a -debug-only=isel. As you could see the >> output type for load, store, and add changes from v4i32 to i32 during >> legalization. How can I preserve the output type to

Hello, Im back trying to finish my backend to a simple RISC cpu SABRE now that most of the tedious process of examining undergraduate students is out of the way. I have managed to describe the registers and the instructions in the architecture and have added support for 32 bit immediates (thanks to Christopher Lamb) as the instruction set only supports 17 bit immediates directly. Could

Hi, I am trying to implement support for an if-conversion pass in a backend for the ADRES CGRA architecture. >From studying the existing IfConversion pass, I observed the following: - The PredicateInstruction method is meant to insert guards into conditional instructions. - This method assumes that one will be able to get the predicate from the conditional branch instruction on which

On Fri, Dec 11, 2009 at 1:49 AM, ether zhhb <etherzhhb at gmail.com> wrote: > hi, > > i have a backend that want to do custom combine on SETCC nodes. > > but some time SETCC was combined into BR_CC before i can visit it to > do my own combine, because DAGCombiner always do its own combine > before custom combine. so, is there anyway to prevent it being > combined

hi, i have a backend that want to do custom combine on SETCC nodes. but some time SETCC was combined into BR_CC before i can visit it to do my own combine, because DAGCombiner always do its own combine before custom combine. so, is there anyway to prevent it being combined without changing the logic of DAGCombiner? thank you very much --ether

Hello, I'd like to write some unit tests which verifies SELECT_CC and BR_CC lowering for ARM target, but I'm almost completely unfamiliar with llvm/Target. How can I get this nodes in DAG? Thanks. -- Kind regards, Dmitry Borisenkov -------------- next part -------------- An HTML attachment was scrubbed... URL:

> > > That's not it at all. These model instructions reading / writing > MVT::Flag a value. That just mean from the scheduler's point of view > the node that produces a MVT::Flag and the user have to be scheduled > together. Wow. That's just super confusing. So SDNPInFlag/SNDPOutFlag is used only for scheduling? I think you're misunderstanding ISD::SETCC.

Howdy, <---stuff deleted -----> Basically the architecture I want to compile to (SABRE) RISC does not support a conditional branch or a select instruction. It supports explicit branches of the form. blt %a, %b, imm // branch on less than iff %a < %b then pc = pc + imm So there are various branch instructions like .... ble, beq, bne, blt, bltu and bleu (unsigned) Im just

Hi, I am having some issues with how some of the instructions are being legalized. So this is my intial basic block. The area of concern is the last three instructions. I will pick and choose debug output to keep this small. SelectionDAG has 36 nodes: t0: ch = EntryToken t6: i32,ch = CopyFromReg t0, Register:i32 %vreg507 t2: i32,ch = CopyFromReg t0, Register:i32 %vreg17

I attempt to optimize the use of the ‘CMP’ instruction on my architecture by removing the instruction instances where the Status Register already had the correct status flags. The cmp instruction in my architecture is the typical one that compares two registers, or a register with an immediate, and sets the Status Flags accordingly. I implemented my ‘cmp’ instruction in LLVM by custom lowering

But isn't kinda silly that we transform to xor and then we transform it back. What is the advantage in doing so? Also, since we do that method, I now have to introduce setcc patterns for i1 values, instead of being able to just use logical pattern operators like not. -Dilan On Fri, Jul 21, 2017 at 11:00 AM Dilan Manatunga <manatunga at gmail.com> wrote: > For some reason I

Hi there, I'm having a hard time with promoting operands from i1 to i32 in my backend... I have to register classes, VTs are i1 and i32. The i1 registers are only for predication and conditional jumps, so I want to use them with brcond, setcc. There are no instructions to directly load a value in an i1 register or to copy between i1 and i32, so I need the DAG Legalizing Pass to not generate

Here's our testcase: #include <stdio.h> struct flags { unsigned frog: 1; unsigned foo : 1; unsigned bar : 1; unsigned bat : 1; unsigned baz : 1; unsigned bam : 1; }; int main() { struct flags flags; flags.bar = 1; flags.foo = 1; if (flags.foo == 1) { printf("Pass\n"); return 0; } else {

I have a back end which has both scalar and vector registers that alias each other. I'm having a problem generating the ISel from tablegen that appears only when a vector register class is declared to contain integer vectors. At that moment tablegen doesn't seem to be able to infer integer types in patterns that it was able to before, but I'm not clear on why that's the

On 12/21/2016 4:45 PM, Phil Tomson via llvm-dev wrote: > Here's our testcase: > > #include <stdio.h> > > struct flags { > unsigned frog: 1; > unsigned foo : 1; > unsigned bar : 1; > unsigned bat : 1; > unsigned baz : 1; > unsigned bam : 1; > }; > > int main() { > struct flags flags; > flags.bar = 1; >

On Sun, 22 Apr 2007, Christopher Lamb wrote: > I have a back end which has both scalar and vector registers that > alias each other. I'm having a problem generating the ISel from > tablegen that appears only when a vector register class is declared > to contain integer vectors. At that moment tablegen doesn't seem to > be able to infer integer types in patterns that it was