search for: replaceuses

...o MOVSDs and a SHUFPD just fine but it produces two extra MOVSD instructions. As far as I can understand things, the problem is that the two MOVSD instructions are generated by a recursive call to EmitResultCode. Thus isRoot is false and the result of the call to getTargetNode is not passed to ReplaceUses. Then when we pop back up and generate the SHUFPD we call SelectNodeTo which only transforms the immediate node (the vector_shuffle). It doesn't recurse to replace child nodes. I tried hacking tblgen to call getTargetNode / ReplaceUses if any node in the pattern has a chain by changing th...

...your latest patch. In summary, it does expose a subtle problem. I haven't seen anything that here would lead to observable misbehavior yet though. X86GenDAGISel.inc has code like this: SDValue N1 = N->getOperand(1); ... SDNode *ResNode = CurDAG->SelectNodeTo(N, ...); ... ReplaceUses(SDValue(N1.getNode(), 1), SDValue(ResNode, 2)); If N was the only user of N1, and N1 isn't in the new operand list, then the SelectNodeTo call will make N1 dead. SelectNodeTo will automatically delete nodes that are made dead by the transformation. This means that the "from" node in...

On Friday 26 February 2010 10:34:41 David Greene wrote: > On Friday 26 February 2010 09:55:32 David Greene wrote: > > In the continuing quest to try to track down problems we're seeing in > > SelectionDAG, I added the following assert > > toSelectionDAG::ReplaceAllUsesOfValuesWith: > > Here's a patch to add more of these deleted node asserts. They fire > tons

Hi I am looking at some of the existing targets to try to understand more about writing a backend. I was a little puzzled by the use of a method ReplaceUses in *ISelDAGToDAG.cpp (*= most targets, e.g. ARM, X86..). I found its definition in the *GenDAGISel.inc file that is autogenerated from the target description. I can only assume TableGen emits this method definition for every traget. Is this method implementation, in some way that I cannot...

...tely observing misbehavior. I know it has something to do with local changes here but I haven't isolated it yet. > X86GenDAGISel.inc has code like this: > > SDValue N1 = N->getOperand(1); > ... > SDNode *ResNode = CurDAG->SelectNodeTo(N, ...); > ... > ReplaceUses(SDValue(N1.getNode(), 1), SDValue(ResNode, 2)); > > If N was the only user of N1, and N1 isn't in the new operand list, then > the SelectNodeTo call will make N1 dead. SelectNodeTo will automatically > delete nodes that are made dead by the transformation. This means that > the &...

On Mon, 2008-10-20 at 11:49 -0500, David Greene wrote: > I tried hacking tblgen to call getTargetNode / ReplaceUses if any node in the > pattern has a chain by changing this line in tblgen: > > bool InputHasChain = isRoot && > NodeHasProperty(Pattern, SDNPHasChain, CGP); > > to call PatternHasProperty instead. This does cause tblgen to emit > getTargetNode / Replac...

...)->setMemRefs(MemOp, MemOp + 1); // Reshuffle LDW's results so that the first two match LOAD's result // type SDValue Unpack[] = { SDValue(LDW, 0), SDValue(LDW, 2), SDValue(LDW, 1) }; SDNode* NN = CurDAG->getMergeValues(Unpack, SDLoc(N)).getNode(); ReplaceUses(N, NN); CurDAG->RemoveDeadNode(N); With this code, I get correct-looking machine instructions, but the node order is all botched up. For example, given this input: SelectionDAG has 8 nodes: t0: ch = EntryToken t2: i16,ch = CopyFromReg t0, Register:i16 %vreg0 t5: i16,ch = lo...

...] = { SDValue(LDW, 0), SDValue(LDW, 2), > SDValue(LDW, 1) }; > SDNode* NN = CurDAG->getMergeValues(Unpack, SDLoc(N)).getNode(); Calling getMergeValues in ISelDAGToDAG is a bad idea; there aren't supposed to be any MERGE_VALUES nodes at that point in the pipeline. You can call ReplaceUses with SDValues rather than SDNodes. -Eli -- Employee of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project

...Operand(4); SDValue op3 = Node->getOperand(5); SDValue Ops[]= { op0, op1, op2, op3, Zero, ChainIn }; SDNode *Result = CurDAG->getMachineNode(Mips::BWT_DROP_RESULT, SDLoc(Node), ReturnValueVT, Ops); ReplaceUses(Node, Result); return std::make_pair(true, Result); Any clues on how INTRINSIC_W_CHAIN differs from INTRINSIC_VOID? Thanks, Ambuj Agrawal -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150309...

...Queue(Op2); unsigned Op; Op = (Opcode == ISD::UMUL_LOHI ? Nios2::MULxu : Nios2::MULx); SDNode *Hi = CurDAG->getTargetNode(Op, MVT::Flag, Op1, Op2); SDNode *Lo = CurDAG->getTargetNode(Nios2::MUL, MVT::Flag, Op1, Op2); if (!N.getValue(0).use_empty()) ReplaceUses(N.getValue(0), SDValue(Lo,0)); if (!N.getValue(1).use_empty()) ReplaceUses(N.getValue(1), SDValue(Hi,0)); return NULL; } The code generator complains: nios2-elf-ecc: /home/rich/llvm-trunk-new/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp:141: void llvm::ScheduleDAG::BuildS...

...#39; ') << "== "; + dbgs() << std::string(Indent-2, ' ') << "== "; Node->dump(CurDAG); - errs() << '\n'; + dbgs() << '\n'; }); Indent -= 2; #endif @@ -1824,9 +1824,9 @@ ReplaceUses(N.getValue(0), Result); #ifndef NDEBUG DEBUG({ - errs() << std::string(Indent-2, ' ') << "=> "; + dbgs() << std::string(Indent-2, ' ') << "=> "; Result.getNode()->dump(CurDAG); - errs(...

...D2PD instructions and the shuffle mask. SelectNodeTo does an in-place replacement of the machine-independent SDNode (vector_shuffle)with a machine-dependent one (the SHUFPD). When we pop back out to SelectRoot we run into this code: if (ResNode != Node) { if (ResNode) { ReplaceUses(Node, ResNode); } if (Node->use_empty()) { // Don't delete EntryToken, etc. ISelQueueUpdater ISQU(ISelQueue); CurDAG->RemoveDeadNode(Node, &ISQU); UpdateQueue(ISQU); } } Since we did an in-placement replacement the first tes...

Dan Gohman wrote: > There certainly are wishlist items for TableGen and TableGen-based > instruction descriptions, though I don't know of an official list. > Offhand, > a few things that come to mind are the ability to handle nodes with > multiple results, Is there an official workaround, BTW? - Volodya

...to do the void Select transition in the version control history - look for commits with "SelectImpl" in the title. That said, the basic playbook I used for conversions went something like this: 1. Avoid leaving dangling nodes around in your Select function - places that currently call ReplaceUses() and then return nullptr often do that. There are examples of this in r269256. 2. Similarly, some places might replace all uses of a node with a new one, then return the new node. Just remove the dead node instead. There was some of this in r269358. 3. Anywhere else where Select returns...

On Mar 1, 2010, at 7:26 AM, David Greene wrote: > >> Perhaps this can be fixed by making the code skip the ReplaceUses >> call in the case where there are no uses to replace. That's not trivial >> to detect though. > > Why not just check the same thing the added asserts check? You mean ->getOpcode() == ISD::DELETED_NODE? That's not fundamentally any better, because if your purpose is...

On Thu, Sep 11, 2008 at 4:31 PM, Arnold Schwaighofer <arnold.schwaighofer at gmail.com> wrote: > Tail calls through function pointers should work.If not please send a testcase. > > I just added the two examples from the bug (1392) that calls for true > tail call support. They work on my machine (-tailcallopt needs to be > enabled) ;) > > That would be commit 56127. >

...dl, LoReg, NVT, InFlag); InFlag = Result.getValue(2); ReplaceUses(SDValue(N, 0), Result); } // Copy the high half of the result, if it is needed. if (!SDValue(N, 1).use_empty()) { SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(),...

On Sep 9, 2010, at 12:59 PM, Borja Ferrer wrote: > Hello, i've noticed a new possible missed optimization while testing more trivial code. > This time it's not a with a xor but with a multiplication instruction and the example is little bit more involved. > > C code: > > typedef short t; > t foo(t a, t b) > { > t a4 = a*b; > return a4; > } >

Thanks Ahmed and also Alex for your replies. This is more or less what I was realising, but it is a great confidence booster to know that it is the correct way also. I can replace all of my various 'Select*' specialisations with version that use 'ReplaceNode/SelectCode' and return 'void', but what about the places where I currently call 'Select(N)' directly?

On Monday 01 March 2010 13:41:12 Dan Gohman wrote: > On Mar 1, 2010, at 7:26 AM, David Greene wrote: > >> Perhaps this can be fixed by making the code skip the ReplaceUses > >> call in the case where there are no uses to replace. That's not trivial > >> to detect though. > > > > Why not just check the same thing the added asserts check? > > You mean ->getOpcode() == ISD::DELETED_NODE? That's not fundamentally > any b...