[AArch64][SVE] LLVM ERROR: Cannot select in llvm.vector.deinterleave3.nxv12i32

[stevesuzuki-arm]

https://godbolt.org/z/e3o9KM8Wa

target triple = "aarch64-linux-gnu"

define void @load_factor3(i32* %ptr, <vscale x 4 x i32>* %s1, <vscale x 4 x i32>* %s2, <vscale x 4 x i32>* %s3) #0 {

  %wide.vec = load <vscale x 12 x i32>, ptr %ptr, align 8
  %ldN = tail call { <vscale x 4 x i32>, <vscale x 4 x i32>, <vscale x 4 x i32> } @llvm.vector.deinterleave3.nxv12i32(<vscale x 12 x i32> %wide.vec)

  %3 = extractvalue { <vscale x 4 x i32>, <vscale x 4 x i32>, <vscale x 4 x i32> } %ldN, 0
  %4 = extractvalue { <vscale x 4 x i32>, <vscale x 4 x i32>, <vscale x 4 x i32> } %ldN, 1
  %5 = extractvalue { <vscale x 4 x i32>, <vscale x 4 x i32>, <vscale x 4 x i32> } %ldN, 2

  store <vscale x 4 x i32> %3, <vscale x 4 x i32>* %s1
  store <vscale x 4 x i32> %4, <vscale x 4 x i32>* %s2
  store <vscale x 4 x i32> %5, <vscale x 4 x i32>* %s3
  ret void
}

declare { <vscale x 4 x i32>, <vscale x 4 x i32>, <vscale x 4 x i32> } @llvm.vector.deinterleave3.nxv12i32(<vscale x 12 x i32>)

llc -mtriple=aarch64-none-elf -mattr=+sve2 -O2

Factor of 2 and 4 works, but 3 fails for all the data types. I expect ld3 is generated in this case.

LLVM ERROR: Cannot select: 0x2a224360: nxv4i32,nxv4i32,nxv4i32 = vector_deinterleave 0x2a224590, 0x2a224750, 0x2a224830
  0x2a224590: nxv4i32,ch = load<(load (<vscale x 1 x s128>) from %ir.ptr, align 8)> 0x2a1aa7e0, 0x2a223cd0, undef:i64
    0x2a223cd0: i64,ch = CopyFromReg 0x2a1aa7e0, Register:i64 %0
  0x2a224750: nxv4i32,ch = load<(load (<vscale x 1 x s128>), align 8)> 0x2a1aa7e0, 0x2a2246e0, undef:i64
    0x2a2246e0: i64 = add nuw 0x2a223cd0, 0x2a224670
      0x2a223cd0: i64,ch = CopyFromReg 0x2a1aa7e0, Register:i64 %0
      0x2a224670: i64 = vscale Constant:i64<16>
  0x2a224830: nxv4i32,ch = load<(load (<vscale x 1 x s128>), align 8)> 0x2a1aa7e0, 0x2a224130, undef:i64
    0x2a224130: i64 = add 0x2a223cd0, 0x2a223fe0
      0x2a223cd0: i64,ch = CopyFromReg 0x2a1aa7e0, Register:i64 %0
      0x2a223fe0: i64 = vscale Constant:i64<32>
In function: load_factor3
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and instructions to reproduce the bug.
Stack dump:
0.	Program arguments: /opt/compiler-explorer/clang-trunk/bin/llc -o /app/output.s -mtriple=aarch64-none-elf -mattr=+sve2 -O2 <source>
1.	Running pass 'Function Pass Manager' on module '<source>'.
2.	Running pass 'AArch64 Instruction Selection' on function '@load_factor3'
 #0 0x0000000003b7eed8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-trunk/bin/llc+0x3b7eed8)
 #1 0x0000000003b7c0a4 SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
 #2 0x0000797ea0642520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #3 0x0000797ea06969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #4 0x0000797ea0642476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #5 0x0000797ea06287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #6 0x00000000007b5b1a llvm::UniqueStringSaver::save(llvm::Twine const&) (.cold) StringSaver.cpp:0:0
 #7 0x0000000003924cba llvm::SelectionDAGISel::CannotYetSelect(llvm::SDNode*) (/opt/compiler-explorer/clang-trunk/bin/llc+0x3924cba)
 #8 0x0000000003928ee9 llvm::SelectionDAGISel::SelectCodeCommon(llvm::SDNode*, unsigned char const*, unsigned int) (/opt/compiler-explorer/clang-trunk/bin/llc+0x3928ee9)
 #9 0x0000000000c3fad7 (anonymous namespace)::AArch64DAGToDAGISel::Select(llvm::SDNode*) AArch64ISelDAGToDAG.cpp:0:0
#10 0x0000000003921e24 llvm::SelectionDAGISel::DoInstructionSelection() (/opt/compiler-explorer/clang-trunk/bin/llc+0x3921e24)
#11 0x000000000392e1e2 llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/opt/compiler-explorer/clang-trunk/bin/llc+0x392e1e2)
#12 0x0000000003930b6a llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) (/opt/compiler-explorer/clang-trunk/bin/llc+0x3930b6a)
#13 0x0000000003932abe llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) (/opt/compiler-explorer/clang-trunk/bin/llc+0x3932abe)
#14 0x00000000039219b1 llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&) (/opt/compiler-explorer/clang-trunk/bin/llc+0x39219b1)
#15 0x0000000002c126ad llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (/opt/compiler-explorer/clang-trunk/bin/llc+0x2c126ad)
#16 0x00000000031747c2 llvm::FPPassManager::runOnFunction(llvm::Function&) (/opt/compiler-explorer/clang-trunk/bin/llc+0x31747c2)
#17 0x0000000003174a51 llvm::FPPassManager::runOnModule(llvm::Module&) (/opt/compiler-explorer/clang-trunk/bin/llc+0x3174a51)
#18 0x0000000003176327 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/opt/compiler-explorer/clang-trunk/bin/llc+0x3176327)
#19 0x00000000008fd479 compileModule(char**, llvm::LLVMContext&) llc.cpp:0:0
#20 0x00000000007ca916 main (/opt/compiler-explorer/clang-trunk/bin/llc+0x7ca916)
#21 0x0000797ea0629d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#22 0x0000797ea0629e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#23 0x00000000008f4ce5 _start (/opt/compiler-explorer/clang-trunk/bin/llc+0x8f4ce5)
Program terminated with signal: SIGSEGV
Compiler returned: 139

[llvmbot]

@llvm/issue-subscribers-backend-aarch64

Author: Steve Suzuki (stevesuzuki-arm)

https://godbolt.org/z/e3o9KM8Wa ``` target triple = "aarch64-linux-gnu"

define void @load_factor3(i32* %ptr, <vscale x 4 x i32>* %s1, <vscale x 4 x i32>* %s2, <vscale x 4 x i32>* %s3) #0 {

%wide.vec = load <vscale x 12 x i32>, ptr %ptr, align 8
%ldN = tail call { <vscale x 4 x i32>, <vscale x 4 x i32>, <vscale x 4 x i32> } @llvm.vector.deinterleave3.nxv12i32(<vscale x 12 x i32> %wide.vec)

%3 = extractvalue { <vscale x 4 x i32>, <vscale x 4 x i32>, <vscale x 4 x i32> } %ldN, 0
%4 = extractvalue { <vscale x 4 x i32>, <vscale x 4 x i32>, <vscale x 4 x i32> } %ldN, 1
%5 = extractvalue { <vscale x 4 x i32>, <vscale x 4 x i32>, <vscale x 4 x i32> } %ldN, 2

store <vscale x 4 x i32> %3, <vscale x 4 x i32>* %s1
store <vscale x 4 x i32> %4, <vscale x 4 x i32>* %s2
store <vscale x 4 x i32> %5, <vscale x 4 x i32>* %s3
ret void
}

declare { <vscale x 4 x i32>, <vscale x 4 x i32>, <vscale x 4 x i32> } @llvm.vector.deinterleave3.nxv12i32(<vscale x 12 x i32>)

`llc -mtriple=aarch64-none-elf -mattr=+sve2 -O2`

Factor of 2 and 4 works, but 3 fails for all the data types. I expect `ld3` is generated in this case.

LLVM ERROR: Cannot select: 0x2a224360: nxv4i32,nxv4i32,nxv4i32 = vector_deinterleave 0x2a224590, 0x2a224750, 0x2a224830
0x2a224590: nxv4i32,ch = load<(load (<vscale x 1 x s128>) from %ir.ptr, align 8)> 0x2a1aa7e0, 0x2a223cd0, undef:i64
0x2a223cd0: i64,ch = CopyFromReg 0x2a1aa7e0, Register:i64 %0
0x2a224750: nxv4i32,ch = load<(load (<vscale x 1 x s128>), align 8)> 0x2a1aa7e0, 0x2a2246e0, undef:i64
0x2a2246e0: i64 = add nuw 0x2a223cd0, 0x2a224670
0x2a223cd0: i64,ch = CopyFromReg 0x2a1aa7e0, Register:i64 %0
0x2a224670: i64 = vscale Constant:i64<16>
0x2a224830: nxv4i32,ch = load<(load (<vscale x 1 x s128>), align 8)> 0x2a1aa7e0, 0x2a224130, undef:i64
0x2a224130: i64 = add 0x2a223cd0, 0x2a223fe0
0x2a223cd0: i64,ch = CopyFromReg 0x2a1aa7e0, Register:i64 %0
0x2a223fe0: i64 = vscale Constant:i64<32>
In function: load_factor3
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and instructions to reproduce the bug.
Stack dump:
0. Program arguments: /opt/compiler-explorer/clang-trunk/bin/llc -o /app/output.s -mtriple=aarch64-none-elf -mattr=+sve2 -O2 <source>

1. Running pass 'Function Pass Manager' on module '<source>'.
2. Running pass 'AArch64 Instruction Selection' on function '@load_factor3'
   #0 0x0000000003b7eed8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-trunk/bin/llc+0x3b7eed8)
   #1 0x0000000003b7c0a4 SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
   #2 0x0000797ea0642520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
   #3 0x0000797ea06969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
   #4 0x0000797ea0642476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
   #5 0x0000797ea06287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
   #6 0x00000000007b5b1a llvm::UniqueStringSaver::save(llvm::Twine const&) (.cold) StringSaver.cpp:0:0
   #7 0x0000000003924cba llvm::SelectionDAGISel::CannotYetSelect(llvm::SDNode*) (/opt/compiler-explorer/clang-trunk/bin/llc+0x3924cba)
   #8 0x0000000003928ee9 llvm::SelectionDAGISel::SelectCodeCommon(llvm::SDNode*, unsigned char const*, unsigned int) (/opt/compiler-explorer/clang-trunk/bin/llc+0x3928ee9)
   #9 0x0000000000c3fad7 (anonymous namespace)::AArch64DAGToDAGISel::Select(llvm::SDNode*) AArch64ISelDAGToDAG.cpp:0:0
   #10 0x0000000003921e24 llvm::SelectionDAGISel::DoInstructionSelection() (/opt/compiler-explorer/clang-trunk/bin/llc+0x3921e24)
   #11 0x000000000392e1e2 llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/opt/compiler-explorer/clang-trunk/bin/llc+0x392e1e2)
   #12 0x0000000003930b6a llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) (/opt/compiler-explorer/clang-trunk/bin/llc+0x3930b6a)
   #13 0x0000000003932abe llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) (/opt/compiler-explorer/clang-trunk/bin/llc+0x3932abe)
   #14 0x00000000039219b1 llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&) (/opt/compiler-explorer/clang-trunk/bin/llc+0x39219b1)
   #15 0x0000000002c126ad llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (/opt/compiler-explorer/clang-trunk/bin/llc+0x2c126ad)
   #16 0x00000000031747c2 llvm::FPPassManager::runOnFunction(llvm::Function&) (/opt/compiler-explorer/clang-trunk/bin/llc+0x31747c2)
   #17 0x0000000003174a51 llvm::FPPassManager::runOnModule(llvm::Module&) (/opt/compiler-explorer/clang-trunk/bin/llc+0x3174a51)
   #18 0x0000000003176327 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/opt/compiler-explorer/clang-trunk/bin/llc+0x3176327)
   #19 0x00000000008fd479 compileModule(char**, llvm::LLVMContext&) llc.cpp:0:0
   #20 0x00000000007ca916 main (/opt/compiler-explorer/clang-trunk/bin/llc+0x7ca916)
   #21 0x0000797ea0629d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
   #22 0x0000797ea0629e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
   #23 0x00000000008f4ce5 _start (/opt/compiler-explorer/clang-trunk/bin/llc+0x8f4ce5)
   Program terminated with signal: SIGSEGV
   Compiler returned: 139

</details>

[Rajveer100]

cc @davemgreen

It looks like something changed after 20.1.0?

[davemgreen]

I don't think anyone has ever added support for these for SVE. (Before clang-19 they were not treated as intrinsics, so turned into normal calls). The load+deinterleave3 should become a ld3 instruction, but the general case is more difficult to efficiently codegen.

[Rajveer100]

I don't think anyone has ever added support for these for SVE. (Before clang-19 they were not treated as intrinsics, so turned into normal calls). The load+deinterleave3 should become a ld3 instruction, but the general case is more difficult to efficiently codegen.

Any possibility of potentially approaching this :)

Also, could you explain what's the challenging part here and relevant pieces to look into?

[davemgreen]

The load+deinterleave3 could be handled by the InterleavedAccessPass. Probably via lowerDeinterleaveIntrinsicToLoad?

Lowering the intrinsic more generically needs a way to shuffle the values into the correct lanes, which for a scalable vector can be difficult. I haven't spent too much time thinking about it, maybe there is a better way than storing it to the stack and reloading with an ld3.