similar to: Strange behaviour of post-legalising optimisations(?)

Is there any way to get it to delay this optimization where it goes from this: Initial selection DAG: BB#0 'bclr64:entry' SelectionDAG has 14 nodes: t0: ch = EntryToken t2: i64,ch = CopyFromReg t0, Register:i64 %vreg0 t4: i64,ch = CopyFromReg t0, Register:i64 %vreg1 t6: i64 = sub t4, Constant:i64<1> t7: i64 = shl Constant:i64<1>, t6

Hi All, I have a question about splitting 'EXTRACT_VECTOR_ELT' with 'v2i1'. I have a llvm IR code snippet as following: llvm IR code snippet: for.body: ; preds = %entry, %for.cond %i.022 = phi i32 [ 0, %entry ], [ %inc, %for.cond ] %0 = icmp ne <2 x i32> %vecinit1, <i32 0, i32 -23> %1 = extractelement <2 x i1>

Setting the ISD::ROTL to Expand doesn't work? (via SetOperation) You could also do a Custom hook if that's what you're looking for. On Thu, Nov 3, 2016 at 5:12 PM, Phil Tomson <phil.a.tomson at gmail.com> wrote: > ... or perhaps to rephrase: > > In 3.9 it seems to be doing a smaller combine much sooner, whereas in 3.6 > it deferred that till later in the

One option may be to prevent the formation of ROTL, if possible, and then generating rol by hand. Marking it as "expand" would likely stop the DAG combiner from creating it. Then you could "preprocess" the selection DAG before the instruction selection and do the pattern matching yourself. -Krzysztof On 11/3/2016 4:24 PM, Phil Tomson via llvm-dev wrote: > I could try

We've recently moved our project from LLVM 3.6 to LLVM 3.9. I noticed one of our code generation tests is breaking in 3.9. The test is: ; RUN: llc < %s -march=xstg | FileCheck %s define i64 @bclr64(i64 %a, i64 %b) nounwind readnone { entry: ; CHECK: bclr r1, r0, r1, 64 %sub = sub i64 %b, 1 %shl = shl i64 1, %sub %xor = xor i64 %shl, -1 %and = and i64 %a, %xor ret i64

> extends the elements to 8bit and stores them on stack. Store is responsible for zero-extend. This is the policy... - Elena -----Original Message----- From: jingu at codeplay.com [mailto:jingu at codeplay.com] Sent: Friday, September 15, 2017 17:45 To: llvm-dev at lists.llvm.org; Demikhovsky, Elena <elena.demikhovsky at intel.com>; daniel_l_sanders at apple.com Subject: Re: Question

Thanks Anton and Krzysztof! Here is the dump using the -debug flag. At this point I am not making much sense of this, would it be too much to ask if one of you could walk me through one of these lines? One thing that I didn't point out is that I never defined any separate floating point registers, not sure if this will pose any issue? Thanks again for your time! Jeff jeff at

Hi all, Our target does not have native support for 64-bit integers, so we rely on library calls for certain operations (like sdiv). We recently ran into a problem where these operations that are expanded to library calls aren't maintaining the proper ordering in relation to other chains in the DAG. The following snippet of a DAG demonstrates the problem. t0: ch = EntryToken t2:

> so I think we need to use non-extending load for element size less than 8bit on "DAGTypeLegalizer::SplitVecOp_EXTRACT_VECTOR_ELT" like this roughly. > if (N->getOperand(0).getValueType().getVectorElementType().getSizeInBits() < 8) { > return DAG.getLoad(N->getValueType(0), dl, Store, StackPtr, MachinePointerInfo()); > } else { > return

Please open a bugzilla ticket and attach your testcase. It will allow us to debug and fix the problem. Thanks - Elena From: JinGu [mailto:jingu at codeplay.com] Sent: Saturday, September 16, 2017 00:38 To: Demikhovsky, Elena <elena.demikhovsky at intel.com>; daniel_l_sanders at apple.com <daniel_l_sanders at apple.com>; Jon Chesterfield <jonathanchesterfield at

Here's the IR I'm trying to compile for my backend, a 16-bit CPU: ; ModuleID = 'foo.c' source_filename = "foo.c" target datalayout = "E-m:e-p16:16:16-i1:16:16-i8:16:16-i16:16:16-i32:16:16-i64:16:16-S16-n16" target triple = "tms9900" @global_var = common global i16 0, align 2 ; Function Attrs: noinline nounwind optnone define signext i16 @dothis(i16

Hi, SystemZ supports @llvm.ctlz.i64() natively with a single instruction (FLOGR), and lesser bitwidth versions of the intrinsic are promoted to i64. For some reason, this leads to unfolded additions of constants as shown below: This function: define i16 @fun(i16 %arg) {   %1 = tail call i16 @llvm.ctlz.i16(i16 %arg, i1 false)   ret i16 %1 } ,gives this optimized DAG as input to instruction

Hello. I'm having problems at instruction selection with my back end with the following basic-block due to a vector add with immediate constant vector (obtained by vectorizing a simple C program doing vector sum map): vector.ph: ; preds = %vector.memcheck50 %.splatinsert = insertelement <8 x i64> undef, i64 %i.07.unr, i32 0

Hi, During instruction selection, I have the following code for certain LOAD instructions: const LoadSDNode *LD = cast<LoadSDNode>(N); SDNode* LDW = CurDAG->getMachineNode(AVR::LDWRdPtr, SDLoc(N), VT, PtrVT, MVT::Other, LD->getBasePtr(), LD->getChain()); // Honestly, I have no idea what this does, but other memory // accessing instructions

Hello, I've hit an assertion in SelectionDAG where we try to merge 2 loads that have the same operands but their MMO flags differ. One is dereferenceable and one is not. I'm not sure what the underlying issue here is: 1) MDSDNode with the same operands should have the same flags set on their respective MMO. The fact the flags differ when the opcode,types,operands and address-space are

Hello, I am getting this error. What instruction is required to be implemented? LLVM ERROR: Cannot select: t22: v32i32 = vselect t724, t11, t16 t724: v32i32,ch = load<LD128[FixedStack1]> t723, FrameIndex:i64<1>, undef:i64 t659: i64 = FrameIndex<1> t10: i64 = undef t11: v32i32,ch = load<LD128[%sunkaddr45](align=4)(tbaa=<0x481f1e8>)> t0, t8, undef:i64

also i further run the following command; llc -debug filer-knl_o3.ll and its output is attached here. by looking at the output can we say that legalization runs fine and the error is due to instruction selection/ pattern matching which is not yet implemented? so do i need to worry and try to correct it at this stage or should i move forward to implement instruction selection/ pattern matching?

Hi Krzysztof, Sure, please see below. DAG.dump.() before and after, annotated with what I believe the DAG means. I've spent some time debugging the method but it's proving difficult to determine where the logic is misfiring. Disabling the entire combine causes a lot of failing x86-64 tests - I may have to learn an upstream vector ISA to make progress on this. Thank you >From your

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

Hello, Tim, Thank you for your advice. Indeed, the problem with "LLVM ERROR: Cannot select" was a false predicate that should have been true. I solved the problem by simply making the C++ function implementing the TableGen predicate used in my store instruction (very similar to the selectIntAddrMSA predicate from the Mips back end) return true instead of false. But