[llvm] [NFC] LLVM reduce: remove unused variable (PR #133584)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-nvptx-nvidia-ubuntu` running on `as-builder-7` while building `llvm` at step 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/180/builds/15569

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

```
Step 5 (build-unified-tree) failure: build (failure)
...
52.965 [30/15/2685] Building CXX object lib/Target/X86/CMakeFiles/LLVMX86CodeGen.dir/X86AsmPrinter.cpp.o
52.999 [30/14/2686] Building CXX object lib/Target/X86/CMakeFiles/LLVMX86CodeGen.dir/X86FixupInstTuning.cpp.o
53.081 [30/13/2687] Building CXX object lib/Target/X86/CMakeFiles/LLVMX86CodeGen.dir/X86ReturnThunks.cpp.o
53.114 [30/12/2688] Building CXX object lib/Target/X86/CMakeFiles/LLVMX86CodeGen.dir/X86InstrInfo.cpp.o
53.199 [30/11/2689] Building CXX object lib/Target/X86/CMakeFiles/LLVMX86CodeGen.dir/X86ISelDAGToDAG.cpp.o
53.347 [30/10/2690] Building CXX object lib/Target/X86/CMakeFiles/LLVMX86CodeGen.dir/X86IndirectBranchTracking.cpp.o
53.359 [30/9/2691] Building CXX object lib/Target/X86/CMakeFiles/LLVMX86CodeGen.dir/X86RegisterInfo.cpp.o
53.515 [30/8/2692] Building CXX object lib/Target/X86/CMakeFiles/LLVMX86CodeGen.dir/X86ISelLowering.cpp.o
53.575 [30/7/2693] Building CXX object lib/Target/X86/CMakeFiles/LLVMX86CodeGen.dir/X86FastPreTileConfig.cpp.o
53.628 [30/6/2694] Building CXX object tools/llvm-reduce/CMakeFiles/llvm-reduce.dir/deltas/ReduceOperandsToArgs.cpp.o
FAILED: tools/llvm-reduce/CMakeFiles/llvm-reduce.dir/deltas/ReduceOperandsToArgs.cpp.o 
CCACHE_CPP2=yes CCACHE_HASHDIR=yes /usr/bin/ccache /usr/bin/c++ -DGTEST_HAS_RTTI=0 -DLLVM_BUILD_STATIC -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/buildbot/worker/as-builder-7/ramdisk/llvm-nvptx-nvidia-ubuntu/build/tools/llvm-reduce -I/home/buildbot/worker/as-builder-7/ramdisk/llvm-nvptx-nvidia-ubuntu/llvm-project/llvm/tools/llvm-reduce -I/home/buildbot/worker/as-builder-7/ramdisk/llvm-nvptx-nvidia-ubuntu/build/include -I/home/buildbot/worker/as-builder-7/ramdisk/llvm-nvptx-nvidia-ubuntu/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -std=c++17 -MD -MT tools/llvm-reduce/CMakeFiles/llvm-reduce.dir/deltas/ReduceOperandsToArgs.cpp.o -MF tools/llvm-reduce/CMakeFiles/llvm-reduce.dir/deltas/ReduceOperandsToArgs.cpp.o.d -o tools/llvm-reduce/CMakeFiles/llvm-reduce.dir/deltas/ReduceOperandsToArgs.cpp.o -c /home/buildbot/worker/as-builder-7/ramdisk/llvm-nvptx-nvidia-ubuntu/llvm-project/llvm/tools/llvm-reduce/deltas/ReduceOperandsToArgs.cpp
/home/buildbot/worker/as-builder-7/ramdisk/llvm-nvptx-nvidia-ubuntu/llvm-project/llvm/tools/llvm-reduce/deltas/ReduceOperandsToArgs.cpp: In function ‘void replaceFunctionCalls(llvm::Function*, llvm::Function*)’:
/home/buildbot/worker/as-builder-7/ramdisk/llvm-nvptx-nvidia-ubuntu/llvm-project/llvm/tools/llvm-reduce/deltas/ReduceOperandsToArgs.cpp:112:29: error: ‘void llvm::FPMathOperator::setFastMathFlags(llvm::FastMathFlags)’ is private within this context
  112 |       FPOp->setFastMathFlags(CI->getFastMathFlags());
      |       ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /home/buildbot/worker/as-builder-7/ramdisk/llvm-nvptx-nvidia-ubuntu/llvm-project/llvm/tools/llvm-reduce/deltas/ReduceOperandsToArgs.cpp:17:
/home/buildbot/worker/as-builder-7/ramdisk/llvm-nvptx-nvidia-ubuntu/llvm-project/llvm/include/llvm/IR/Operator.h:264:8: note: declared private here
  264 |   void setFastMathFlags(FastMathFlags FMF) {
      |        ^~~~~~~~~~~~~~~~
53.683 [30/5/2695] Building CXX object lib/Target/X86/CMakeFiles/LLVMX86CodeGen.dir/X86FixupSetCC.cpp.o
53.692 [30/4/2696] Building CXX object lib/Target/X86/CMakeFiles/LLVMX86CodeGen.dir/X86OptimizeLEAs.cpp.o
53.811 [30/3/2697] Building CXX object lib/Target/X86/CMakeFiles/LLVMX86CodeGen.dir/GISel/X86InstructionSelector.cpp.o
53.841 [30/2/2698] Building CXX object lib/Target/X86/CMakeFiles/LLVMX86CodeGen.dir/X86ISelLoweringCall.cpp.o
53.906 [30/1/2699] Building CXX object lib/Target/X86/CMakeFiles/LLVMX86CodeGen.dir/X86MCInstLower.cpp.o
ninja: build stopped: subcommand failed.

```

</details>

https://github.com/llvm/llvm-project/pull/133584