[CLANG_X] Loop not vectorized in MkFit

[iarspider]

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>> Compiling (...)/cms/cmssw/CMSSW_14_1_CLANG_X_2024-02-06-2300/src/RecoTracker/MkFitCore/src/radix_sort.cc
/data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/llvm/17.0.3-58617194c079c8f35fd2aa0eeb9674ef/bin/clang++ -c -DGNU_GCC -D_GNU_SOURCE -DTBB_USE_GLIBCXX_VERSION=120301 -DTBB_SUPPRESS_DEPRECATED_MESSAGES -DTBB_PREVIEW_RESUMABLE_TASKS=1 -DTBB_PREVIEW_TASK_GROUP_EXTENSIONS=1 -DCMSSW_GIT_HASH='CMSSW_14_1_CLANG_X_2024-02-06-2300' -DPROJECT_NAME='CMSSW' -DPROJECT_VERSION='CMSSW_14_1_CLANG_X_2024-02-06-2300' -I/data/cmsbld/jenkins/workspace/build-any-ib/w/tmp/BUILDROOT/4653e4858633c7925b084632648ff40c/opt/cmssw/el8_amd64_gcc12/cms/cmssw/CMSSW_14_1_CLANG_X_2024-02-06-2300/src -I/data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/pcre/8.43-37eb2e8b73bab83d6645ecfd5d73dcaa/include -I/data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/bz2lib/1.0.6-d065ccd79984efc6d4660f410e4c81de/include -isystem/data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/lcg/root/6.30.05-0bda4ba0a0084b1b4c83e4b8f805f59c/include -isystem/data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/tbb/v2021.9.0-5109e373398eaf79a8268d6a86a2f6e2/include -I/data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/cms/vdt/0.4.3-5a80085534117eaccb28e669c6da4b6f/include -I/data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/xz/5.2.5-6f3f49b07db84e10c9be594a1176c114/include -I/data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/zlib/1.2.11-51072030b7f93c3ac6c4235f21e413cb/include -I/data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/json/3.11.3-2540d984125d8aab890b619b66fd01ff/include -O2 -pthread -pipe -Werror=main -Werror=pointer-arith -Werror=overlength-strings -Wno-vla -Werror=overflow -std=c++17 -ftree-vectorize -Werror=array-bounds -Werror=type-limits -fvisibility-inlines-hidden -fno-math-errno --param vect-max-version-for-alias-checks=50 -Xassembler --compress-debug-sections -Wno-error=array-bounds -Warray-bounds -fuse-ld=bfd -msse3 -felide-constructors -fmessage-length=0 -Wall -Wno-long-long -Wreturn-type -Wextra -Wpessimizing-move -Wclass-memaccess -Wno-cast-function-type -Wno-unused-but-set-parameter -Wno-ignored-qualifiers -Wno-unused-parameter -Wunused -Wparentheses -Werror=return-type -Werror=missing-braces -Werror=unused-value -Werror=unused-label -Werror=address -Werror=format -Werror=sign-compare -Werror=write-strings -Werror=delete-non-virtual-dtor -Werror=strict-aliasing -Werror=narrowing -Werror=reorder -Werror=unused-variable -Werror=conversion-null -Wnon-virtual-dtor -Werror=switch -fdiagnostics-show-option -Wno-unused-local-typedefs -Wno-attributes -Wno-psabi -Wno-deprecated-copy -Wno-deprecated -Wno-c99-extensions -Wno-c++11-narrowing -D__STRICT_ANSI__ -Wno-unused-private-field -Wno-unknown-pragmas -Wno-unused-command-line-argument -Wno-unknown-warning-option -ftemplate-depth=512 -Wno-error=potentially-evaluated-expression -Wno-tautological-type-limit-compare -fsized-deallocation --gcc-toolchain=/data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/gcc/12.3.1-40d504be6370b5a30e3947a6e575ca28 -Ofast -fno-reciprocal-math -mrecip=none -DBOOST_DISABLE_ASSERTS -fopenmp-simd -fPIC -MMD -MF tmp/el8_amd64_gcc12/src/RecoTracker/MkFitCore/src/RecoTrackerMkFitCore/radix_sort.cc.d /data/cmsbld/jenkins/workspace/build-any-ib/w/tmp/BUILDROOT/4653e4858633c7925b084632648ff40c/opt/cmssw/el8_amd64_gcc12/cms/cmssw/CMSSW_14_1_CLANG_X_2024-02-06-2300/src/RecoTracker/MkFitCore/src/radix_sort.cc -o tmp/el8_amd64_gcc12/src/RecoTracker/MkFitCore/src/RecoTrackerMkFitCore/radix_sort.cc.o
  (...)/cms/cmssw/CMSSW_14_1_CLANG_X_2024-02-06-2300/src/RecoTracker/MkFitCore/src/PropagationMPlex.cc:1086:8: warning: loop not vectorized: the optimizer was unable to perform the requested transformation; the transformation might be disabled or specified as part of an unsupported transformation ordering [-Wpass-failed=transform-warning]
  1086 |   void propagateHelixToPlaneMPlex(const MPlexLS& inErr,
      |        ^
  (...)/cms/cmssw/CMSSW_14_1_CLANG_X_2024-02-06-2300/src/RecoTracker/MkFitCore/src/PropagationMPlex.cc:1086:8: warning: loop not vectorized: the optimizer was unable to perform the requested transformation; the transformation might be disabled or specified as part of an unsupported transformation ordering [-Wpass-failed=transform-warning]
 2 warnings generated.

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A new Issue was created by @iarspider .

@antoniovilela, @rappoccio, @Dr15Jones, @sextonkennedy, @makortel, @smuzaffar can you please review it and eventually sign/assign? Thanks.

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[iarspider]

assign RecoTracker/MkFitCore

[cmsbuild]

New categories assigned: reconstruction

@jfernan2,@mandrenguyen you have been requested to review this Pull request/Issue and eventually sign? Thanks

[iarspider]

@dan131riley it seems that the fix in #43725 was not enough?

[slava77]

pointer to

1086 |   void propagateHelixToPlaneMPlex(

is not very helpful in the context of "loop is not vectorized" message.
Is there a way to point to the actual code with the loop?

This seems more connected to #41730 (and the discussion in #41624 ).
It looks like we may need to add more #if !defined(__clang__) around #pragma omp simd

[dan131riley]

This is caused by changes introduced in #43146. Compiling with "-g" resolves where the problems are--I'm looking at whether those loops vectorize (or should vectorize) with the various compilers.

/mnt/data1/dsr/CMSSW_14_1_CLANG_X_2024-02-06-2300/src/RecoTracker/MkFitCore/src/PropagationMPlex.cc:231:1: warning: loop not vectorized: the optimizer was unable to perform the requested transformation; the transformation might be disabled or specified as part of an unsupported transformation ordering [-Wpass-failed=transform-warning]
  231 | #pragma omp simd
      | ^
/mnt/data1/dsr/CMSSW_14_1_CLANG_X_2024-02-06-2300/src/RecoTracker/MkFitCore/src/PropagationMPlex.cc:245:1: warning: loop not vectorized: the optimizer was unable to perform the requested transformation; the transformation might be disabled or specified as part of an unsupported transformation ordering [-Wpass-failed=transform-warning]
  245 | #pragma omp simd
      | ^
2 warnings generated.