[llvm] [LV] Ignore some costs when loop gets fully unrolled (PR #106699)

Mon Dec 9 10:25:40 PST 2024

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `libc-x86_64-debian-dbg-runtimes-build` running on `libc-x86_64-debian` while building `llvm` at step 4 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/78/builds/11135

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

```
Step 4 (annotate) failure: 'python ../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py ...' (failure)
...
Running: ninja libc
[1/38] Generating VCSRevision.h
[2/38] Generating VCSVersion.inc
[3/38] Building CXX object tools/clang/lib/Basic/CMakeFiles/obj.clangBasic.dir/Version.cpp.o
[4/38] Building CXX object tools/llvm-config/CMakeFiles/llvm-config.dir/llvm-config.cpp.o
[5/38] Linking CXX executable bin/llvm-config
[6/38] Building CXX object lib/Object/CMakeFiles/LLVMObject.dir/IRSymtab.cpp.o
[7/38] Linking CXX static library lib/libLLVMObject.a
[8/38] Linking CXX static library lib/libclangBasic.a
[9/38] Building CXX object lib/Transforms/Vectorize/CMakeFiles/LLVMVectorize.dir/LoopVectorize.cpp.o
FAILED: lib/Transforms/Vectorize/CMakeFiles/LLVMVectorize.dir/LoopVectorize.cpp.o 
/usr/bin/clang++ -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/build/lib/Transforms/Vectorize -I/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/llvm-project/llvm/lib/Transforms/Vectorize -I/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/build/include -I/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -g  -fno-exceptions -funwind-tables -fno-rtti -std=c++17 -MD -MT lib/Transforms/Vectorize/CMakeFiles/LLVMVectorize.dir/LoopVectorize.cpp.o -MF lib/Transforms/Vectorize/CMakeFiles/LLVMVectorize.dir/LoopVectorize.cpp.o.d -o lib/Transforms/Vectorize/CMakeFiles/LLVMVectorize.dir/LoopVectorize.cpp.o -c /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:2699:49: error: reference to local binding 'IV' declared in enclosing function 'addFullyUnrolledInstructionsToIgnore'
               [&](const User *U) { return U == IV || U == Cmp; }))
                                                ^
/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:2694:21: note: 'IV' declared here
  for (const auto &[IV, IndDesc] : IL) {
                    ^
1 error generated.
[10/38] Linking CXX executable bin/llvm-size
[11/38] Linking CXX executable bin/llvm-objcopy
[12/38] Linking CXX executable bin/llvm-readobj
[13/38] Linking CXX executable bin/sanstats
[14/38] Linking CXX executable bin/llvm-symbolizer
[15/38] Linking CXX executable bin/llvm-cov
[16/38] Linking CXX executable bin/llvm-xray
[17/38] Linking CXX executable bin/obj2yaml
[18/38] Linking CXX executable bin/llvm-ar
[19/38] Linking CXX executable bin/llvm-profdata
[20/38] Linking CXX executable bin/sancov
[21/38] Linking CXX executable bin/llvm-objdump
[22/38] Linking CXX executable bin/llvm-nm
[23/38] Building CXX object lib/CodeGen/AsmPrinter/CMakeFiles/LLVMAsmPrinter.dir/AsmPrinter.cpp.o
[24/38] Building CXX object lib/LTO/CMakeFiles/LLVMLTO.dir/LTO.cpp.o
ninja: build stopped: subcommand failed.
['ninja', 'libc'] exited with return code 1.
The build step threw an exception...
Traceback (most recent call last):
  File "/home/llvm-libc-buildbot/home/sivachandra/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/build/../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py", line 160, in step
    yield
  File "/home/llvm-libc-buildbot/home/sivachandra/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/build/../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py", line 124, in main
    run_command(['ninja', 'libc'])
  File "/home/llvm-libc-buildbot/home/sivachandra/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/build/../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py", line 175, in run_command
    util.report_run_cmd(cmd, cwd=directory)
  File "/home/llvm-libc-buildbot/home/sivachandra/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/llvm-zorg/zorg/buildbot/builders/annotated/util.py", line 49, in report_run_cmd
    subprocess.check_call(cmd, shell=shell, *args, **kwargs)
  File "/usr/lib/python3.11/subprocess.py", line 413, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['ninja', 'libc']' returned non-zero exit status 1.
Step 6 (build libc) failure: build libc (failure)
...
Running: ninja libc
[1/38] Generating VCSRevision.h
[2/38] Generating VCSVersion.inc
[3/38] Building CXX object tools/clang/lib/Basic/CMakeFiles/obj.clangBasic.dir/Version.cpp.o
[4/38] Building CXX object tools/llvm-config/CMakeFiles/llvm-config.dir/llvm-config.cpp.o
[5/38] Linking CXX executable bin/llvm-config
[6/38] Building CXX object lib/Object/CMakeFiles/LLVMObject.dir/IRSymtab.cpp.o
[7/38] Linking CXX static library lib/libLLVMObject.a
[8/38] Linking CXX static library lib/libclangBasic.a
[9/38] Building CXX object lib/Transforms/Vectorize/CMakeFiles/LLVMVectorize.dir/LoopVectorize.cpp.o
FAILED: lib/Transforms/Vectorize/CMakeFiles/LLVMVectorize.dir/LoopVectorize.cpp.o 
/usr/bin/clang++ -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/build/lib/Transforms/Vectorize -I/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/llvm-project/llvm/lib/Transforms/Vectorize -I/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/build/include -I/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -g  -fno-exceptions -funwind-tables -fno-rtti -std=c++17 -MD -MT lib/Transforms/Vectorize/CMakeFiles/LLVMVectorize.dir/LoopVectorize.cpp.o -MF lib/Transforms/Vectorize/CMakeFiles/LLVMVectorize.dir/LoopVectorize.cpp.o.d -o lib/Transforms/Vectorize/CMakeFiles/LLVMVectorize.dir/LoopVectorize.cpp.o -c /home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:2699:49: error: reference to local binding 'IV' declared in enclosing function 'addFullyUnrolledInstructionsToIgnore'
               [&](const User *U) { return U == IV || U == Cmp; }))
                                                ^
/home/llvm-libc-buildbot/buildbot-worker/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:2694:21: note: 'IV' declared here
  for (const auto &[IV, IndDesc] : IL) {
                    ^
1 error generated.
[10/38] Linking CXX executable bin/llvm-size
[11/38] Linking CXX executable bin/llvm-objcopy
[12/38] Linking CXX executable bin/llvm-readobj
[13/38] Linking CXX executable bin/sanstats
[14/38] Linking CXX executable bin/llvm-symbolizer
[15/38] Linking CXX executable bin/llvm-cov
[16/38] Linking CXX executable bin/llvm-xray
[17/38] Linking CXX executable bin/obj2yaml
[18/38] Linking CXX executable bin/llvm-ar
[19/38] Linking CXX executable bin/llvm-profdata
[20/38] Linking CXX executable bin/sancov
[21/38] Linking CXX executable bin/llvm-objdump
[22/38] Linking CXX executable bin/llvm-nm
[23/38] Building CXX object lib/CodeGen/AsmPrinter/CMakeFiles/LLVMAsmPrinter.dir/AsmPrinter.cpp.o
[24/38] Building CXX object lib/LTO/CMakeFiles/LLVMLTO.dir/LTO.cpp.o
ninja: build stopped: subcommand failed.
['ninja', 'libc'] exited with return code 1.
The build step threw an exception...
Traceback (most recent call last):
  File "/home/llvm-libc-buildbot/home/sivachandra/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/build/../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py", line 160, in step
    yield
  File "/home/llvm-libc-buildbot/home/sivachandra/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/build/../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py", line 124, in main
    run_command(['ninja', 'libc'])
  File "/home/llvm-libc-buildbot/home/sivachandra/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/build/../llvm-zorg/zorg/buildbot/builders/annotated/libc-linux.py", line 175, in run_command
    util.report_run_cmd(cmd, cwd=directory)
  File "/home/llvm-libc-buildbot/home/sivachandra/libc-x86_64-debian/libc-x86_64-debian-dbg-runtimes-build/llvm-zorg/zorg/buildbot/builders/annotated/util.py", line 49, in report_run_cmd
    subprocess.check_call(cmd, shell=shell, *args, **kwargs)
  File "/usr/lib/python3.11/subprocess.py", line 413, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['ninja', 'libc']' returned non-zero exit status 1.

```

</details>

https://github.com/llvm/llvm-project/pull/106699