[llvm] DAG: Avoid comparing Register to unsigned 0 (PR #155164)

Mon Aug 25 00:03:16 PDT 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `sanitizer-x86_64-linux-fast` running on `sanitizer-buildbot3` while building `llvm` at step 2 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/169/builds/14366

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 2 (annotate) failure: 'python ../sanitizer_buildbot/sanitizers/zorg/buildbot/builders/sanitizers/buildbot_selector.py' (failure)
...
llvm-lit: /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:527: note: using lld-link: /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/lld-link
llvm-lit: /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:527: note: using ld64.lld: /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/ld64.lld
llvm-lit: /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:527: note: using wasm-ld: /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/wasm-ld
llvm-lit: /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:527: note: using ld.lld: /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/ld.lld
llvm-lit: /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:527: note: using lld-link: /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/lld-link
llvm-lit: /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:527: note: using ld64.lld: /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/ld64.lld
llvm-lit: /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:527: note: using wasm-ld: /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/wasm-ld
llvm-lit: /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/utils/lit/lit/main.py:74: note: The test suite configuration requested an individual test timeout of 0 seconds but a timeout of 900 seconds was requested on the command line. Forcing timeout to be 900 seconds.
-- Testing: 92243 tests, 88 workers --
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90
FAIL: LLVM :: tools/llvm-exegesis/RISCV/rvv/filter.test (26050 of 92243, 3 of 3 attempts)
******************** TEST 'LLVM :: tools/llvm-exegesis/RISCV/rvv/filter.test' FAILED ********************
Exit Code: 2

Command Output (stderr):
--
/home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/llvm-exegesis -mtriple=riscv64 -mcpu=sifive-x280 -benchmark-phase=assemble-measured-code --mode=inverse_throughput --opcode-name=PseudoVNCLIPU_WX_M1_MASK     --riscv-filter-config='vtype = {VXRM: rod, AVL: VLMAX, SEW: e(8|16), Policy: ta/mu}' --max-configs-per-opcode=1000 --min-instructions=10 | /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/FileCheck /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/tools/llvm-exegesis/RISCV/rvv/filter.test # RUN: at line 1
+ /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/FileCheck /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/tools/llvm-exegesis/RISCV/rvv/filter.test
+ /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/llvm-exegesis -mtriple=riscv64 -mcpu=sifive-x280 -benchmark-phase=assemble-measured-code --mode=inverse_throughput --opcode-name=PseudoVNCLIPU_WX_M1_MASK '--riscv-filter-config=vtype = {VXRM: rod, AVL: VLMAX, SEW: e(8|16), Policy: ta/mu}' --max-configs-per-opcode=1000 --min-instructions=10
PseudoVNCLIPU_WX_M1_MASK: Failed to produce any snippet via: instruction has tied variables, avoiding Read-After-Write issue, picking random def and use registers not aliasing each other, for uses, one unique register for each position
FileCheck error: '<stdin>' is empty.
FileCheck command line:  /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/FileCheck /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/tools/llvm-exegesis/RISCV/rvv/filter.test

--

********************
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90..
Slowest Tests:
--------------------------------------------------------------------------
330.22s: LLVM :: CodeGen/AMDGPU/memintrinsic-unroll.ll
289.27s: LLVM :: CodeGen/AMDGPU/amdgcn.bitcast.1024bit.ll
153.28s: LLVM :: CodeGen/AMDGPU/sched-group-barrier-pipeline-solver.mir
93.03s: Clang :: Analysis/runtime-regression.c
86.92s: Clang :: CodeGen/AArch64/sve-intrinsics/acle_sve_reinterpret.c
76.29s: LLVM :: CodeGen/AMDGPU/amdgcn.bitcast.512bit.ll
72.74s: Clang :: CodeGen/X86/avx512f-builtins.c
64.15s: LLVM :: CodeGen/AMDGPU/amdgcn.bitcast.960bit.ll
63.89s: LLVM :: CodeGen/X86/vector-interleaved-load-i8-stride-8.ll
59.89s: LLVM :: CodeGen/RISCV/rvv/expandload.ll
58.23s: Clang :: Driver/fsanitize.c
58.12s: Clang :: CodeGen/X86/avx-builtins.c
58.11s: LLVM :: MC/Mips/mips-jump-pc-region.s
58.00s: Clang :: Analysis/PR24184.cpp
57.57s: LLVM :: CodeGen/AMDGPU/amdgcn.bitcast.896bit.ll
53.49s: LLVM :: CodeGen/AMDGPU/amdgcn.bitcast.832bit.ll
53.21s: Clang :: Headers/arm-neon-header.c
53.13s: Clang :: CodeGen/X86/rot-intrinsics.c
51.59s: LLVM :: CodeGen/AMDGPU/bf16.ll
49.37s: LLVM :: CodeGen/AMDGPU/amdgcn.bitcast.768bit.ll
Step 14 (stage2/msan check) failure: stage2/msan check (failure)
...
llvm-lit: /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:527: note: using lld-link: /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/lld-link
llvm-lit: /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:527: note: using ld64.lld: /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/ld64.lld
llvm-lit: /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:527: note: using wasm-ld: /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/wasm-ld
llvm-lit: /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:527: note: using ld.lld: /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/ld.lld
llvm-lit: /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:527: note: using lld-link: /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/lld-link
llvm-lit: /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:527: note: using ld64.lld: /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/ld64.lld
llvm-lit: /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/utils/lit/lit/llvm/config.py:527: note: using wasm-ld: /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/wasm-ld
llvm-lit: /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/utils/lit/lit/main.py:74: note: The test suite configuration requested an individual test timeout of 0 seconds but a timeout of 900 seconds was requested on the command line. Forcing timeout to be 900 seconds.
-- Testing: 92243 tests, 88 workers --
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90
FAIL: LLVM :: tools/llvm-exegesis/RISCV/rvv/filter.test (26050 of 92243, 3 of 3 attempts)
******************** TEST 'LLVM :: tools/llvm-exegesis/RISCV/rvv/filter.test' FAILED ********************
Exit Code: 2

Command Output (stderr):
--
/home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/llvm-exegesis -mtriple=riscv64 -mcpu=sifive-x280 -benchmark-phase=assemble-measured-code --mode=inverse_throughput --opcode-name=PseudoVNCLIPU_WX_M1_MASK     --riscv-filter-config='vtype = {VXRM: rod, AVL: VLMAX, SEW: e(8|16), Policy: ta/mu}' --max-configs-per-opcode=1000 --min-instructions=10 | /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/FileCheck /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/tools/llvm-exegesis/RISCV/rvv/filter.test # RUN: at line 1
+ /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/FileCheck /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/tools/llvm-exegesis/RISCV/rvv/filter.test
+ /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/llvm-exegesis -mtriple=riscv64 -mcpu=sifive-x280 -benchmark-phase=assemble-measured-code --mode=inverse_throughput --opcode-name=PseudoVNCLIPU_WX_M1_MASK '--riscv-filter-config=vtype = {VXRM: rod, AVL: VLMAX, SEW: e(8|16), Policy: ta/mu}' --max-configs-per-opcode=1000 --min-instructions=10
PseudoVNCLIPU_WX_M1_MASK: Failed to produce any snippet via: instruction has tied variables, avoiding Read-After-Write issue, picking random def and use registers not aliasing each other, for uses, one unique register for each position
FileCheck error: '<stdin>' is empty.
FileCheck command line:  /home/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/FileCheck /home/b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/tools/llvm-exegesis/RISCV/rvv/filter.test

--

********************
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90..
Slowest Tests:
--------------------------------------------------------------------------
330.22s: LLVM :: CodeGen/AMDGPU/memintrinsic-unroll.ll
289.27s: LLVM :: CodeGen/AMDGPU/amdgcn.bitcast.1024bit.ll
153.28s: LLVM :: CodeGen/AMDGPU/sched-group-barrier-pipeline-solver.mir
93.03s: Clang :: Analysis/runtime-regression.c
86.92s: Clang :: CodeGen/AArch64/sve-intrinsics/acle_sve_reinterpret.c
76.29s: LLVM :: CodeGen/AMDGPU/amdgcn.bitcast.512bit.ll
72.74s: Clang :: CodeGen/X86/avx512f-builtins.c
64.15s: LLVM :: CodeGen/AMDGPU/amdgcn.bitcast.960bit.ll
63.89s: LLVM :: CodeGen/X86/vector-interleaved-load-i8-stride-8.ll
59.89s: LLVM :: CodeGen/RISCV/rvv/expandload.ll
58.23s: Clang :: Driver/fsanitize.c
58.12s: Clang :: CodeGen/X86/avx-builtins.c
58.11s: LLVM :: MC/Mips/mips-jump-pc-region.s
58.00s: Clang :: Analysis/PR24184.cpp
57.57s: LLVM :: CodeGen/AMDGPU/amdgcn.bitcast.896bit.ll
53.49s: LLVM :: CodeGen/AMDGPU/amdgcn.bitcast.832bit.ll
53.21s: Clang :: Headers/arm-neon-header.c
53.13s: Clang :: CodeGen/X86/rot-intrinsics.c
51.59s: LLVM :: CodeGen/AMDGPU/bf16.ll
49.37s: LLVM :: CodeGen/AMDGPU/amdgcn.bitcast.768bit.ll

```

</details>

https://github.com/llvm/llvm-project/pull/155164