similar to: [LLVMdev] Backend: 2 address + 17bit immediate

Hi all, This seems like a dumb question but while setting up a pattern in TD file, I got stuck on trying to get each half of an immediate as the half-sized type (ie. i64 imm -> pair of i32 imm's). Is there an existing way to do it? I've tried the 'EXTRACT_SUBREG' but that seems to error at the end of scheduling. Looking at Target.td, I'm not sure which opcode is meant

Hi Kevin, To get some portion of a constant immediate you can use SDNodeXForms to transform constant SDNodes into other values. For a worked example, in the MIPS backend we use this for constant synthesis by materializing the value into a register: (From lib/Target/MipsInstrInfo.td): // Transformation Function - get the lower 16 bits. def LO16 : SDNodeXForm<imm, [{ return getImm(N,

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

Hello, Ive started writing a backend to a simple 32bit RISC processor core with the goal of undertaking some flexible instruction processor core research on FPGAs and also to use it for teaching computer architecture. I have a requirement to generate instructions like below, where the (17bit) immediate value is (preferably) omitted if it has a zero value. add %15, %14 add %12, %23 - 18 mov

I was able to resolve my previous question about dealing with custom loads/stores, and following Chris' suggestion, the IBM Cell SPU backend can generate code for "int main(void) { return 0; }" without crashing llc. There's a lot of work still to be done... like getting frame offsets correctly computed and hauling in the raft of intrinsics that the Cell SDK defines. Three quick

On Sun, Nov 22, 2015 at 1:28 AM, Rui Ueyama <ruiu at google.com> wrote: > I'm not sure if I understand the semantics of HI16 and LO16 relocations. If > my understanding is correct, a pair of HI16 and LO16 represents an addend > AHL. AHL is computed by (AHI<<16) | (ALO&0xFFFF). Can't we apply HI16 and > LO16 relocations separately and produce the same relocation

Hi, I have a problem regarding sub-register definitions and LiveIntervals on our target. When a subregister is defined, other parts of the register are always left untouched - they are neither read or def:ed. It however seems that Codegen treats subregister definitions as somehow clobbering the whole register. The SSA-code looks like this after isel: (Reg0 and Reg1 are 16bit registers. Reg2,

Hi Quentin, On 08/15/14 19:01, Quentin Colombet wrote: [...] >> The question is: How should true subregister definitions be >> expressed so that they do not interfere with each other? See the >> detailed problem description below. > > We do have a limitation in our current liveness tracking for > sub-register. Therefore, I am not sure that is possible. > >

On Tue, 9 Jan 2007, Evan Cheng wrote: >> - How does one deal with multiple instruction sequences in a pattern? >> To load a constant is a two instruction sequence, but both >> instructions only take two operands (assume that r3 is a 32-bit >> register): >> >> ilhu $3, 45 # r3 = (45 << 16) >> iohl $3, 5 # r3 |= 5

Hi there, I am doing relocation in my backend by calling my function getAddrNonPic: SDValue getAddrNonPIC(NodeTy *N, SDLoc DL, EVT Ty, SelectionDAG &DAG)const{ SValue Hi=getTarget(N,Ty,DAG, MyBackend::Hi16); SValue Lo=getTarget(N,Ty,DAG, MyBackend::Lo16); return DAG.getNode(ISD::ADD, DL, Ty, DAG.getNode(MyBackend::Hi16, DL, Ty, Hi), DAG.getNode(MyBackend::Lo16, DL, Ty, Ho)); }

On Sat, Nov 21, 2015 at 10:08 AM, Rui Ueyama <ruiu at google.com> wrote: > On Fri, Nov 20, 2015 at 11:02 PM, Simon Atanasyan <simon at atanasyan.com> > wrote: >> >> On Sat, Nov 21, 2015 at 9:28 AM, Rui Ueyama <ruiu at google.com> wrote: >> > On Fri, Nov 20, 2015 at 10:13 PM, Simon Atanasyan <simon at atanasyan.com> >> > wrote: >>

Hi, I am combining 16-bit registers to a 32 bit register in order to make a wide store, as per below: 732 %reg16506:hi16<def,dead> = COPY %reg16445<kill>; 740 %reg16506:lo16<def> = COPY %reg16468<kill>; 748 %r3<def,dead> = store %reg16506<kill>, %r3, As you can see, LiveVariables has marked the high part dead, even though the super-register is used at

On Jan 9, 2007, at 10:01 AM, Scott Michel wrote: > I was able to resolve my previous question about dealing with custom > loads/stores, and following Chris' suggestion, the IBM Cell SPU > backend > can generate code for "int main(void) { return 0; }" without crashing > llc. There's a lot of work still to be done... like getting frame > offsets correctly

On May 19, 2011, at 7:47 AM, Jonas Paulsson wrote: > Hi, > > I am combining 16-bit registers to a 32 bit register in order to make a wide store, as per below: > > 732 %reg16506:hi16<def,dead> = COPY %reg16445<kill>; > 740 %reg16506:lo16<def> = COPY %reg16468<kill>; > 748 %r3<def,dead> = store %reg16506<kill>, %r3, > > As you can

On Sat, Nov 21, 2015 at 9:28 AM, Rui Ueyama <ruiu at google.com> wrote: > On Fri, Nov 20, 2015 at 10:13 PM, Simon Atanasyan <simon at atanasyan.com> > wrote: >> >> In case of MIPS O32 ABI we have to find a matching R_MIPS_LO16 >> relocation to calculate R_MIPS_HI16 one because R_MIPS_HI16 uses >> combined addend (AHI << 16) + (short)ALO where AHI is

Hi, I'm having an issue with subregisters on my target. With a pseudo that writes to a 32 bit reg: %vreg20<def> = toHi16_low0_pseudo %vreg2; reg32:%vreg20 hi16:%vreg2 expands to %vreg2<def> = COPY %a2h; hi16:%vreg2 %vreg43<def> = mov 0, pred:0, pred:%noreg, %ac0<imp-use>, %ac1<imp-use>; lo16:%vreg43 %vreg20<def> =

If I write %reg16506<def> = INSERT_SUBREG %reg16506, %reg16445, hi16; #1 %reg16506<def> = INSERT_SUBREG %reg16506, %reg16468, lo16; #2 store %reg16506 #3 it will not coalesce, as LiveVariables: on #2: %16506 gets #2 as a kill #3: %16506 gets #3 as an additional kill LiveIntervalAnalysis:

Hi, I am working on support R_MIPS_HI16 / R_MIPS_LO16 in the new LLD and have a couple of questions. == Q1 In case of MIPS O32 ABI we have to find a matching R_MIPS_LO16 relocation to calculate R_MIPS_HI16 one because R_MIPS_HI16 uses combined addend (AHI << 16) + (short)ALO where AHI is original R_MIPS_HI16 addend and ALO is addend of the matching R_MIPS_LO16 relocation [1]. There are two

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

+llvmdev -llvmcommits On Fri, Nov 12, 2010 at 8:03 AM, Jim Grosbach <grosbach at apple.com> wrote: > Sorta. getBinaryCodeForInst() is auto-generated by tablegen, so shouldn't be modified directly. The target can register hooks for instruction operands for any special encoding needs, including registering fixups, using the EncoderMethod string. For an example, have a look at the