similar to: Which way to lower selects on architectures without conditional moves&

Hi all, I'm playing with intrinsics and I was wondering how to lower an intrinsic that should return, for example, an int1? More precisely, how to return the value when working with MachineInst? First, I have defined an instrinsic in "Intrinsics.td": _def int_antivm : Intrinsic<[llvm_i1_ty], [], [], "llvm.antivm">;_ Then I want to lower it in the X86 backend,

Hi, A number of transforms are actually independent, so here's a partial fix. I updated the dependencies in a cluster of transforms: LowerSwitch, Mem2Reg, LowerSelect, LowerAllocations, UnifyFunctionExitNodes. The patch has been tested, but not extensively. PassManager doesn't complain, and the result of a test pass that requires all these (except for LowerAllocations) together works

On Jun 3, 2011, at 2:59 AM, Galanov, Sergey wrote: > Hi, Bill and Jakob. > > I don't quite understand. I am talking about CMOV_GR* instructions which are conservatively marked as clobbering EFLAGS in X86InstrCompiler.td. Doesn't that mean there cannot be any use of EFLAGS in subsequent instructions before it is defined by some other instruction? > > I also don't

Eli, Thanks for the tips. I've been able to get something working using a custom instruction inserter, however, I'm still having the problem of linking together the setcc and the select_cc commands. I want to turn the setcc into a comparison and use the results in the select_cc register. However, the comparison information is in the select_cc instruction and the result of the comparison

Hi, I was wondering if LLVM supports predicates and conditional execution. Something like we have in IA64. There is a register class of predicates and then every instruction may be predicated by a register from this class. For example: cmp_less p, x, y // p is a predicate which gets the result of x < y p add x, x, 2 // if p then do the add instruction Is there support in LLVM to something

Hi, I was evaluating all transformation passes and noticed a few things. In particular, I found three passes in the documentation that I can't seem to find any code for. Where these removed? Lower GC intrinsics, for GCless code generators (-lowergc) Correlated Expression Elimination (-cee) Lower select instructions to branches (-lowerselect) Additionally, I found the following passes for

Thanks for spelling it out, now I understand. On Jun 5, 2011, at 6:11 AM, Galanov, Sergey wrote: > Well, the point is CMOV_GR* are marked clobbering EFLAGS conservatively just in case they turn out to be lowered into a sequence containing XOR %reg,%reg which indeed clobbers EFLAGS. This means there might not be any instruction which actually uses this EFLAGS value. This actually looks like a

Hi Bill. Thank you very much! Now I see my understanding was incorrect :) A dependence from a single physreg-defining instruction (like CMP or TEST) is allowed to be shared in several instructions unless that register is not clobbered (and this is what we have with CMOV_FR64). Wouldn't it be safe then to not set the live-in flag in EmitLoweredSelect for instructions which are marked as

Hello, My expansion for an operation uses if and loops. How do I introduce branches in the target lowering stage? Do I have to create basic blocks, add the instructions to them and and add them to the machine function's basic block list? Thanks, Javier

Well, the point is CMOV_GR* are marked clobbering EFLAGS conservatively just in case they turn out to be lowered into a sequence containing XOR %reg,%reg which indeed clobbers EFLAGS. This means there might not be any instruction which actually uses this EFLAGS value. For an example we can look no further than the actual test which has been disabled after the fix

Hi, Few more questions that I found while trying to develop a new backend. And sorry if I ask too many questions. 1) My target (embedded processor, which is a "not so direct" successor of Z80 family of processors) does not support SELECT, so I was looking for a workaround. First I was thinking about expanding it into conditional flow with branching, but then I have found that there

Hi Serge, Thanks for your help. I have looked at the change log, and so far as I can tell, my implementation is pretty much identical to all of the in-tree targets, but I’m missing something and can’t see what it is. I have simplified my TD description to just: def MyCallseqStart : SDNode<"ISD::CALLSEQ_START", SDCallSeqStart<[SDTCisVT<0, i32>,

On Jun 2, 2011, at 12:58 PM, Bill Wendling wrote: > On Jun 2, 2011, at 3:53 AM, Galanov, Sergey wrote: > >> Hi Bill. >> >> Thank you very much! Now I see my understanding was incorrect :) A dependence from a single physreg-defining instruction (like CMP or TEST) is allowed to be shared in several instructions unless that register is not clobbered (and this is what we

Hi Rafael, Thanks for the answers. > > 1) My target (embedded processor, which is a "not so direct" > successor > > of Z80 family of processors) does not support SELECT, so I was > looking > > for a workaround. > > > > First I was thinking about expanding it into conditional flow with > > branching, but then I have found that there exists a

I'm tracking down an X86 code generation malfeasance regarding BT (bit test) and I have some questions. This IR *matches* and then *X86TargetLowering::LowerToBT **is called:* %and = and i64 %shl, %val * ; (val & (1 << index)) != 0 ; *bit test with a *register* index This IR *does not match* and so *X86TargetLowering::LowerToBT **is not called:* %and = lshr i64 %val, 25

Hi, I'm trying to implement a target-agnostic intrinsic, first targeting X86. I'm trying to map the intrinsic SD node to an instruction with a certain target opcode that I've introduced. The issue that I'm running into is what the correct way to lower the argument is. I've done a couple loops on the docs so any help would be appreciated! Some options I've explored but have

On Mon, 2 Oct 2006, Roman Levenstein wrote: >>> Wouldn't it be possible and even more clean to have just one >>> description like (I use a pseudo-description here): >>> >>> def MOVrr : I<0x88, MRMDestReg, (ops (GR8|GR16|GR32) :$dst, >>> (i8mem|i16mem|i32mem):$src), >>> "mov{b} {$src, $dst|$dst, $src}", []>,

On Jun 2, 2011, at 3:53 AM, Galanov, Sergey wrote: > Hi Bill. > > Thank you very much! Now I see my understanding was incorrect :) A dependence from a single physreg-defining instruction (like CMP or TEST) is allowed to be shared in several instructions unless that register is not clobbered (and this is what we have with CMOV_FR64). Wouldn't it be safe then to not set the live-in

Hi Evan, first off thanks to you and Chris for taking time. On 6 Sep 2007, at 00:57, Evan Cheng wrote: > We'd like to see tail call optimization to be similar to the target > independent lowering of ISD::CALL nodes. These are auto-generated > from ???CallingConv.td files. Some target specific details such as > function address register (ECX in your example) should be coded in

On 10/3/06, Roman Levenstein <romixlev at yahoo.com> wrote: > Hi, > > Few more questions that I found while trying to develop a new backend. > And sorry if I ask too many questions. I only have answers to some of them: > 1) My target (embedded processor, which is a "not so direct" successor > of Z80 family of processors) does not support SELECT, so I was looking