similar to: Instruction is selected, but it shouldn't (?)

Hi Eli, Thanks for your response. Actually, I look a lot at the ARM and THUMB1 backend implementations, and this certainly help. My architecture also have specific instructions for SP-relative accesses in a similar way than the Thumb1. During frame lowering, specific machine instructions are emitted so there’s no issue there. Also during ISelDagToDag I am able to select the right instructions.

Hi, I'm trying to implement a new backend for an embedded CISC processor. Therefore I thought that it makes sense to take X86 target as a basis, to save some time. But when I look into the X86InstrInfo.td, I have a very strong feeling that it is one of the most complex instruction set descriptions compared to other targets. I can imagine that this is due to the complexity of X86's

On Sun, 1 Oct 2006, Roman Levenstein wrote: > I'm trying to implement a new backend for an embedded CISC processor. > Therefore I thought that it makes sense to take X86 target as a basis, > to save some time. Ok. Note that the X86 backend is one of the most complex though, because it supports several subtargets and ABIs, which makes it more complex than some other targets. >

Hi everyone, I am puzzled by several instruction defines in MSP430. 1 def MOV16rr : Pseudo<(outs GR16:$dst), (ins GR16:$src), "mov.w\t{$src, $dst}", [ ]>; Because it's an empty dag pattern[ ], by what does instuction selector select intruction 'MOV16rr'? 2 let canFoldAsLoad = 1, isReMaterializable = 1, mayHaveSideEffects =

Hi, 1. This instruction is not selected automatically by the instruction selector. The instruction combine / select stages insert registercopies, and they are expanded later on by the copyRegToReg() function provided by the MSP430InstrInfo to this MOV16rr. 2. ReMaterializable means there is no need to find a way to preserve the value in a register : the instruction can be just be reissued

Hi, while writing my register allocator, I have come across a case which confuses me because the llvm definition cannot be mapped to machine code. For instance I come across (1) and I reduce it to (2). However a copy instruction cannot move from EDX to CX. What mechanics in LLVM will tell me that I cannot make this move during register allocation, or how can I tell from (1) that I cannot execute

Hi Chris, Thanks a lot for your answer! Chris Lattner wrote: >> 1. Why does X86 instruction set description provide different >> descriptions for the same instructions, which differ only in the size >> of operands? >> E.g. >> >> def MOV8rm : I<0x8A, MRMSrcMem, (ops GR8 :$dst, i8mem :$src), >> "mov{b} {$src, $dst|$dst, $src}",

Hi, This patch fixes outs/ins of MOV16mr instruction of X86. Thanks. diff --git a/lib/Target/X86/X86InstrInfo.td b/lib/Target/X86/X86InstrInfo.td index e9a0431..f5b2064 100644 --- a/lib/Target/X86/X86InstrInfo.td +++ b/lib/Target/X86/X86InstrInfo.td @@ -1412,7 +1412,7 @@ let SchedRW = [WriteStore] in { def MOV8mr : I<0x88, MRMDestMem, (outs), (ins i8mem :$dst, GR8 :$src),

Hi, Yuanke, Thanks for writing this up. Let me back up a bit because the scheme I proposed last week doesn't work without further modification: within a particular "configuration region" (i.e., the code in between the LDTILECFG and the TILERELEASE (or next LDTILECFG)), each tile register can only be used with one shape, and in addition, no register can have its shape changed

On 9/4/20 3:37 AM, Luo, Yuanke wrote: > > Hi Hal, > > Thank you for the ideas that help us to improve the design, and sorry > for replying late. There is something I am not able to figure out and > there some special trait for tile RA. > You're quite welcome. > 1.X86RegisterInfo::getRegAllocationHints can tell RA which physical > register is preferred, but it

On Nov 8, 2010, at 12:04 PM, Jeff Kunkel wrote: > Hi, while writing my register allocator, I have come across a case which confuses me because the llvm definition cannot be mapped to machine code. > > For instance I come across (1) and I reduce it to (2). However a copy instruction cannot move from EDX to CX. What mechanics in LLVM will tell me that I cannot make this move during

Hi I'm returning to my MC6809 back-end from a health-related hiatus. The assembler is tantalisingly close, but I've got some parsing and matching problems. The register set; these overlap in annoying ways, for instance, two instructions TFR and EXG each have a single opcode, and the post-byte specifies which registers are to be involved, but the registers can be 8- or 16-bit, and 2 of

Fix typo From: Luo, Yuanke Sent: Friday, September 4, 2020 9:47 PM To: 'Hal Finkel' <hfinkel at anl.gov>; Topper, Craig <craig.topper at intel.com>; Kaylor, Andrew <andrew.kaylor at intel.com>; Philip Reames <listmail at philipreames.com>; llvm-dev at lists.llvm.org; florian_hahn at apple.com; Lu, Hongjiu <hongjiu.lu at intel.com> Subject: RE: [llvm-dev]

>I am assuming a 16-bit value will be stored in a pair of 8-bit > registers? One related question is how to make sure that the correct register pair is allocated to the16-bit quantity when using two 8-bit operations. In other words, how we can make sure that the 16-bit pointer is stored into [AH, AL] and not in [AH, BL] ? i.e. GR8 = [ AH, BH, AL, BL]; GR16 = [AX, BX] ; // AX, BX

On Wed, Jul 10, 2013 at 12:29 PM, Ramkumar Ramachandra <artagnon at gmail.com> wrote: > The instructions btr and bts are perfectly valid, and have existed since > Intel 386. GNU as supports them fine. Unfortunately, LLVM does not > support them, and barfs with: > > error: ambiguous instructions require an explicit suffix > > Fix this problem by disambiguating it

Hi All, I've developed a pass to render machine functions as HTML pages with some accompanying information about liveness and register pressure. Current features: Renders machine functions, optionally displaying estimated register pressure for selected register classes, and liveness for selected intervals. The following command line options can be used to enable and customise the

Hi Hal, The proposal is attractive to me, but there is something I still can't figure out. Let's take below MIR as an example. We assume we have 256 register classes (vtile1x1, vtile1x2, ..., tile16x16). 1. After instruction selection, the pseudo AMX instruction is generated. The name of pseudo instructions have 'P' prefix. Now all the AMX pseudo instruction take vtile as

Hi, in X86InstrArithmetic.td, we have LEA16r defined as: def LEA16r : I<0x8D, MRMSrcMem, (outs GR16:$dst), (ins i32mem:$src), "lea{w}\t{$src|$dst}, {$dst|$src}", [], IIC_LEA_16>, OpSize16; Please correct me if I am wrong, but I think "ins i32mem" should be "ins i16mem" because this is about 16bit register? So is this a

On Oct 7, 2011, at 11:23 AM, David A. Greene wrote: > Evan Cheng <evan.cheng at apple.com> writes: > >> Your proposed new TableGen functionalities are interesting but it is >> clearly not where the code owners want it to go. > > Jakob at least seems interested in the for loop stuff. Am I reading you > correctly, Jakob? Having that feature would make a huge

Hi All, My target has some instructions requiring register pairs. I decided to give a try to the PBQP allocator : it is working fine in 99% of the cases, but I am stumbling on the following issue. Instruction 'MPQD' takes 3 register operands inputs, with the constraint that operands 0 and 2 must be consecutive registers. Operand 1 has no particular constraint. It has no output register.