<table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Issue</th>
<td>
<a href=https://github.com/llvm/llvm-project/issues/55127>55127</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>
AArch64 UDOT "Cannot select" error
</td>
</tr>
<tr>
<th>Labels</th>
<td>
new issue
</td>
</tr>
<tr>
<th>Assignees</th>
<td>
</td>
</tr>
<tr>
<th>Reporter</th>
<td>
rootjalex
</td>
</tr>
</table>
<pre>
LLVM appears to be failing in instruction selection when compiling the attached matmul_aarch64.ll file with llc.
`llc` is built from branch `release/14.x`, with the most recent commit being ebf29ba9f0a3a1076c613aef59e65d65435daaee .
Trace:
```
31-35-226:matmul ajroot$ /Users/ajroot/llvm-install-14/bin/llc matmul_aarch64.ll -o temp.s
LLVM ERROR: Cannot select: t1824: v4i32 = AArch64ISD::UDOT t63, t1826, t58
t63: v4i32,ch = load<(load (s128) from %ir.2663, !tbaa !12)> t0, t62, undef:i64
t62: i64 = add nuw t49, Constant:i64<32>
t49: i64,ch = CopyFromReg t0, Register:i64 %592
t48: i64 = Register %592
t61: i64 = Constant<32>
t4: i64 = undef
t1826: v16i8 = AArch64ISD::ZIP2 t1829, t1828
t1829: v16i8 = AArch64ISD::ZIP1 t5, t11
t5: v16i8,ch = load<(load (s128) from %ir.lsr.iv167179, align 4, !tbaa !15)> t0, t2, undef:i64
t2: i64,ch = CopyFromReg t0, Register:i64 %601
t1: i64 = Register %601
t4: i64 = undef
t11: v16i8,ch = load<(load (s128) from %ir.scevgep180181, align 2, !tbaa !15)> t0, t10, undef:i64
t10: i64 = add t2, t9
t2: i64,ch = CopyFromReg t0, Register:i64 %601
t1: i64 = Register %601
t9: i64 = AssertSext t7, ValueType:ch:i33
t7: i64,ch = CopyFromReg t0, Register:i64 %35
t6: i64 = Register %35
t4: i64 = undef
t1828: v16i8 = AArch64ISD::ZIP1 t26, t32
t26: v16i8,ch = load<(load (s128) from %ir.scevgep195196, align 1, !tbaa !15)> t0, t25, undef:i64
t25: i64 = add t2, t24
t2: i64,ch = CopyFromReg t0, Register:i64 %601
t1: i64 = Register %601
t24: i64 = AssertSext t22, ValueType:ch:i32
t22: i64,ch = CopyFromReg t0, Register:i64 %7
t21: i64 = Register %7
t4: i64 = undef
t32: v16i8,ch = load<(load (s128) from %ir.scevgep197198, align 1, !tbaa !15)> t0, t31, undef:i64
t31: i64 = add t2, t30
t2: i64,ch = CopyFromReg t0, Register:i64 %601
t1: i64 = Register %601
t30: i64 = AssertSext t28, ValueType:ch:i34
t28: i64,ch = CopyFromReg t0, Register:i64 %25
t27: i64 = Register %25
t4: i64 = undef
t58: v16i8 = bitcast t1827
t1827: v4i32 = AArch64ISD::DUP t1328
t1328: i32,ch = load<(load (s32) from %ir.scevgep157158, !tbaa !17)> t0, t46, undef:i64
t46: i64 = add t43, t45
t43: i64,ch = CopyFromReg t0, Register:i64 %588
t42: i64 = Register %588
t45: i64,ch = CopyFromReg t0, Register:i64 %602
t44: i64 = Register %602
t4: i64 = undef
In function: matmul_aarch64_llvm14_par_for_multiplied_no_offsets_s1_y_y
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0. Program arguments:/Users/ajroot/llvm-install-14/bin/llc bin/matmul_aarch64.ll -o temp.s
1. Running pass 'Function Pass Manager' on module 'bin/matmul_aarch64.ll'.
2. Running pass 'AArch64 Instruction Selection' on function '@matmul_aarch64_llvm14_par_for_multiplied_no_offsets_s1_y_y'
Stack dump without symbol names (ensure you have llvm-symbolizer in your PATH or set the environment var `LLVM_SYMBOLIZER_PATH` to point to it):
0 llc 0x000000010faf0267 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 39
1 llc 0x000000010faeede8 llvm::sys::RunSignalHandlers() + 248
2 llc 0x000000010faf08b0 SignalHandler(int) + 272
3 libsystem_platform.dylib 0x00007fff71fdb5fd _sigtramp + 29
4 libsystem_platform.dylib 000000000000000000 _sigtramp + 18446603338603711008
5 libsystem_c.dylib 0x00007fff71eb1808 abort + 120
6 llc 0x000000010fa218c8 llvm::report_fatal_error(llvm::Twine const&, bool) + 456
7 llc 0x000000010f94dd41 llvm::SelectionDAGISel::CannotYetSelect(llvm::SDNode*) + 1009
8 llc 0x000000010f94acf0 llvm::SelectionDAGISel::SelectCodeCommon(llvm::SDNode*, unsigned char const*, unsigned int) + 20928
9 llc 0x000000010e126daf (anonymous namespace)::AArch64DAGToDAGISel::Select(llvm::SDNode*) + 37887
10 llc 0x000000010f940053 llvm::SelectionDAGISel::DoInstructionSelection() + 1491
11 llc 0x000000010f93e98b llvm::SelectionDAGISel::CodeGenAndEmitDAG() + 6411
12 llc 0x000000010f93bc91 llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) + 7841
13 llc 0x000000010f937f72 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) + 2754
14 llc 0x000000010ed3bd4a llvm::MachineFunctionPass::runOnFunction(llvm::Function&) + 362
15 llc 0x000000010f1f3e0f llvm::FPPassManager::runOnFunction(llvm::Function&) + 1199
16 llc 0x000000010f1fad98 llvm::FPPassManager::runOnModule(llvm::Module&) + 72
17 llc 0x000000010f1f4551 llvm::legacy::PassManagerImpl::run(llvm::Module&) + 1041
18 llc 0x000000010d916eb5 compileModule(char**, llvm::LLVMContext&) + 7397
19 llc 0x000000010d914c9f main + 1327
20 libdyld.dylib 0x00007fff71de2cc9 start + 1
Abort trap: 6
```
[matmul_aarch64.txt](https://github.com/llvm/llvm-project/files/8567903/matmul_aarch64.txt)
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzNWUtv4zYQ_jXOhYghPvQ6-OA4SRtg0w2S7ALtxaAkytauJBoSlaz76zskpVh-K24PNYxE5mPmm5mPwxk7ksl68uXL90fEVyvBqxopiSKBUp7lWblAWQnvWlVNrDJZolrkwj69L0WJYlms7Dq1FIgrxeOlSFDBVdHkc86reOmxcZ6jNMsFes_UEuV5PB45tyNn2v71HBiCvyirUdRkuUJpJQsUVbyMlwgmKtDJazEi95iNf8HAiMysLK20kLVClYhFqTScIlMAXyMSUUrCiIepwynHju_FHqZcpG4oPDfxXEbdhHMh0Bac14rHYkQ34Nq3-UjxNXWvCfFggbUR8R-VlGpEGAJ832pR1fC_G7zP87fiWvuP5_k1ZjASZaUZjw846VoiJYrVuLbaTFTunp-_PoM6NONlKVUbAD2gcECYfnhjGSVoRG_RdGpkPbzcagvo9Nvt11ekPKodppd75sENrHxkpjoBMKXdDVJyyZMRnY1IoJ_ArqDGJBiR0AZmRNysGhPPih0RrCLO9X8MMsIRvUPKREh5WiZqykSkoCXzWKcWmTlQDGNGI08SVDbvSLFQb5lJ7bFStbvoDNDRu81uZBba_RvYM7la3wPAZ7FoEcBTVitRWTkauBuSvhgtKOgD6XYcWKs83F-5wbiLTrH-Omt-528TA-1x7GXBwZD99fBEzLqwC1rQE23Gz-3HEGK7GW8Z4H7s_GSs87oaZ7DRx75BxfNsUSK2G353O_zHo2_QkIsC6Dl4W452yrEI7i0-ERorCV_qojoWbwuxwoGDA7zxETnjI-ycdhLM7xwT61YV7nnhP_PnpzyKNJTe4mkNKVC9iF8KKV-r_M7zRryuVzqnxkutmNIDGv2L0FN3X5Q-qcfg764_yQd79gYctjat0u100TvoF3IpdHHobbiEz50398yBc49wibD_D5kIO8YmQo7QiRzQSS4zwD9IJ3LUAv9z6YWSf00JH4fBcEpQfJoSFB-hBHX-P5SgzlFKBEcosUdoZBZfYgA5nGKIf8yE3Q2nygF3J79EmYo5lLM69fjbmcg_XendfnuCZbRfLKB2QGs_U97p6YN8c33sBrsk87dJxrzTJGPeHsmYrUjZnm_1zEV1XRAcCDkjx4J0YL1GcxnDDyUgxo5TfK8EPUKQhxKlTWm6Lb1iu1-Y69YCs_mKV_NUVnOYUtkqz0QyL-VcpmktVD2v8Xw9X1txT1_upi93qG4i3SNx6LUW0DetZKV0y7dUalVrLpF7eC-gu2qiMfRTbRPT9TKrSv7Q_Qe5z-q6EbrZQbxMoEeM8yYRpiOLK14vUcTjn0o3U2179QK94U-UNMXqo7tyxtYDT5VcVLxAvFo0BfRxLY5PdVP26WxPhVuVz01Z6iZxxesaouLft45GT3rgkZd8AUEmPoKhQiYNdK_w6YgSmGmNJEfEt8cVPfRa6ZeulW7VdLHW60fM-Rfh7nLHxuWmXZYNtI_rIpI5KnkhNLBAlHVTCbSWDVryN4GMi-2i7G8gLLT_MFehp-nr70hW0H4qE2NRvmWVLHW00BuvdJuu29X5y5-PN1-_PPx19zzXW3RbD-Rayaw0LMuUyR1d_JH-NgAdfDm_HPvCTspTh3i-wWazXb2u7cNTBYKNmbZvh5z2saji73MJ7hYc2GtyFKzVeW5EbhBtC2g8FIIQiQgOQYBQv8BdzPPf4RzkhrFBp4WwNs2Q4ZYGkYO2BIK8HnDit-mDgsgsAhhA7_kq5wpoUYyTNQy2Iv00TX2cJpGbJmheZws4jkAFI6U1n50SsvfaEYIDxjzPoZQG8NfH2HFac92-2LiVt2WuxSYiaJgCxCOdhIxI0hYe3lCHERzE_bjYjDZPOSSJuagqWW2R4vU9KyFD6ea9JUUkZd45l7meVe8PVB-yJGG4p_7jUN9Of3uAD3bUfnfzp1B2egvRy-0fMgHmTjsQ4MY2OsFgFDxOnbMo7OgMtM1kUei8cxiGvswh0KVIULyEs916a3umT0kn7OqOcBhigYmX8FQnIF7Kcl3IprY5aWVOcWgxtVkTjHiVByw57UbqB0GbB7Ez1I-O49KzfryVvTTey-Ifxx6zsC1jMR6omYowiM7zCEz8TZTTMrmDOxymeko91n3dg8lQpVEcnievHZ3m-Q2vs_gml_HPesv1H3fn5lhZSH7AOkh0KCQ_9clZSFVTfi0febyEw9xp34K0N-dt8qfbFqiYDeNqQqOEcXRUuK4YerAO4jkAhHptIsfuMN_glAon7eG4f9Kqu1rl8wgwDrtb0BsKgSdhMADCoymZtkPSDm3Y0dnvD1XOXLdP11wseLxuC4ENjIditaHJaQjY-SBoMAhEEmJPRG77u4f4MFPnSZN7TJLcaNQ10UyWCtrVvuU07DJTOFQti8MUWoCstMBpV-MRR1-1cMMm29fsRoK9ahNB4jhEUDt3V63dPzV3L1zquixH3sGfPUbuzU7Nq8Ae9xYM_3TboH8I0kV94Hp-6ND9clqLJuFVMqFJSEN-pTKVi0lXQJtfNEaEbP8aQggyV_1VU-WTyzsZoBfxr5YTTnzh8pQl2CFxAjkyinEqwoimwuEkoFc5j0ReT8AvoLoU78iIgGdwylU2IQ4hDiO-gwkl3ph7jJCIEpG62AtjB4p7AZHMxxrHWFaLq2piIEFHVsNkDr1ivZkEZusrVxh1IJ83UMpXE90T_eC5-HVllE8M-H8AIMyiVA">