similar to: Instruction selection problems due to SelectionDAGBuilder

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>

> 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

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

Hello. I am writing a back end in which I combined the existing BPF LLVM back end with the Mips MSA vector extensions (from the Mips back end) I have encountered an error when compiling with llc: the instruction selector uses a vector register instead of a scalar register with type i64 . I have the following part of LLVM IR program: vector.body.preheader:

> 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

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

Is there an established way of disabling a DAG combine on a per target basis, where it appears to be detrimental to the generated code? Writing if (!mytarget) in DAGCombiner.cpp works but tends to be erased by git merge and generally doesn't look ideal. Writing the inverse transform in target specific code doesn't work in this instance and in general creates an infinite loop. Guidance

Hi, I'm trying to optimize the 'extract_vector_elt' for my SIMD microcontroller. The idea is, during DAG combination, to merge load/extract sequence into an architecture specific node. During Instruction Selection, this specific node will be target selected to an architecture specific instruction. By 'combination of DAG nodes' I understand 'replacing a set of DAG nodes by

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

I have the following selection DAG: SelectionDAG has 9 nodes: t0: ch = EntryToken t2: i64,ch = CopyFromReg t0, Register:i64 %vreg0 t16: i32,ch = load<LD1[%ptr](tbaa=<0x10023c9f448>), anyext from i8> t0, t2, undef:i64 t15: v16i8 = BUILD_VECTOR t16, t16, t16, t16, t16, t16, t16, t16, t16, t16, t16, t16, t16, t16, t16, t16 t11: ch,glue = CopyToReg t0, Register:v16i8 %V2, t15

This post is related to the following post http://lists.llvm.org/pipermail/llvm-dev/2016-April/098823.html I'm still trying to compile a library with clang. But now I'm getting as assert in lib/CodeGen/TargetLoweringBase.cpp:1155: virtual llvm::EVT llvm::TargetLoweringBase::getSetCCResultType(llvm::LLVMContext&, llvm::EVT) const: Assertion `!VT.isVector() && "No default

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

I am hoping that someone can offer advice on a somewhat unusual issue that I am facing with the SDAG. Namely, I am trying to implement some custom operations that do very specific things on multiple registers at a time. The operations themselves will simply be intrinsics since there are no equivalent operations in IR/SDAG. However, handling the types seems rather tricky. One approach I tried is

Hello, LLVM devs. I'm compiling the following simple IR: define dso_local i32 @main(i32 %argc, i8** %argv) { entry: %retval = alloca i32, align 4 %argc.addr = alloca i32, align 4 %argv.addr = alloca i8**, align 8 store i32 0, i32* %retval, align 4 store i32 %argc, i32* %argc.addr, align 4 store i8** %argv, i8*** %argv.addr, align 8 ret i32 0 } using `llc -march=sparc

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:

Hi All, I have a problem with VectorLegalizer::ExpandStore() with v4i1. Let's see a example. * LLVM IR store <4 x i1> %edgeMask_for.body1314, <4 x i1>* %27 * SelectionDAG before vector legalization ch = store<ST1[%16](align=4), trunc to v4i1> t0, t128, t32, undef:i64 * SelectionDAG after vector legalization ch = store<ST1[%16](align=4), trunc to i1> t0, t133, t32,

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

I'd like to start a discussion about how clang supports _Float16 for target architectures that don't have direct support for 16-bit floating point arithmetic. The current clang language extensions documentation says, "If half-precision instructions are unavailable, values will be promoted to single-precision, similar to the semantics of __fp16 except that the results will be stored

Hi All, Can someone comment below question whether it is wrong or not please? 2016-06-25 7:52 GMT+01:00 jingu kang <jaykang10 at gmail.com>: > Hi All, > > I have a problem with VectorLegalizer::ExpandStore() with v4i1. > > Let's see a example. > > * LLVM IR > store <4 x i1> %edgeMask_for.body1314, <4 x i1>* %27 > > * SelectionDAG before vector

Hi, I vaguely remember hitting something like this when I was implementing MSA. IIRC, there was an optimization (in DAGCombine or somewhere around there) that was folding CopyToReg instructions into the load without checking whether the new register class was acceptable. I remember adding a target hook to limit this optimization based on the EVT's involved but I'm not sure if that's