similar to: [LLVMdev] combine ISD::SETCC by custom routine

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

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

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

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

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 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

I am implementing a new backend and am pretty sure I don't quite understand "the way" one is supposed to implement conditional branches. My target CPU natively supports a conditional branch instruction that accepts a condition to test (equal, less than, etc.), two operands (two registers, or one register and one immediate), and finally a target PC to branch to if the comparison

Hi, I'm investigating an issue with the PTX backend I've come across (latest version from the trunk). Not being very familiar with Selection Dags, it's highly likely that I misunderstand some part of the process. I'd appreciate if someone can point me in the right direction. Here's the LLVM IR that is causing problems (I'm aware this code doesn't do anything

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

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, >> DAGCombiner::visitBRCOND() has code: >> >> SDValue N1 = N->getOperand(1); >> SDValue N2 = N->getOperand(2); >> >> ... >> >> SDNode *Trunc = 0; >> if (N1.getOpcode() == ISD::TRUNCATE&& N1.hasOneUse()) { >> // Look past truncate. >> Trunc = N1.getNode(); >> N1 = N1.getOperand(0);

Bill Wendling wrote: > On Sep 29, 2010, at 12:36 AM, Heikki Kultala wrote: > >> On 29 Sep 2010, at 06:25, Heikki Kultala wrote: >> >>> Our architecture has 1-bit boolean predicate registers. >>> >>> I've defined comparison >>> >>> def NErrb : InstTCE<(outs I1Regs:$op3), (ins I32Regs:$op1,I32Regs:$op2), "", [(set

After a hiatus on the CellSPU development, I've got all of the instructions necessary to get the llvm-gcc frontend to build. I've now discovered a new and interesting problem that I'm not sure how to solve cleanly and it's due to the fact that CellSPU has no fixed size condition flags. CellSPU's condition flags depend on the size of what's being compared, i.e., if both

Background: The Cell SPU does not have condition registers in the normal sense. It fits the "zero or negative one" model, preferably with an i32 register, which is what getSetCCResultType() will return. Problem: LegalizeTypes promotes i1 to i8 via an i32 setcc, i.e., the generated type legalization is: (i8:truncate (i32:setcc i32:lhs, i32:rhs, ch:cond)) How do I keep

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

On Sep 30, 2010, at 2:13 AM, Heikki Kultala wrote: > Bill Wendling wrote: >> On Sep 29, 2010, at 12:36 AM, Heikki Kultala wrote: >> >>> On 29 Sep 2010, at 06:25, Heikki Kultala wrote: >>> >>>> Our architecture has 1-bit boolean predicate registers. >>>> >>>> I've defined comparison >>>> >>>> def

Hi all, I've spent the day trying to understand setcc/select_cc intricacies, and I thought I should mention that so far as I can tell, the modeling of CPU flags, condition codes and therefore conditional instructions seems pretty broken. On the one hand there are the SDNPInFlag/SDNPOutFlag node properties which allow you to mark an instruction as using or def-ing the CPU flags

You can tell LLVM that you have "sign extended" setCC results (all ones). Dan On Nov 18, 2008, at 5:33 PM, Eli Friedman wrote: > On Tue, Nov 18, 2008 at 1:56 PM, Villmow, Micah > <Micah.Villmow at amd.com> wrote: >> The IR produces correct results, but my backend does not and the >> only thing >> I can think of is that the IR is treating the

> > > 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.

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; >