[llvm] [NFC] Switch a number of DenseMaps to SmallDenseMaps for speedup (PR #109417)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `arc-builder` running on `arc-worker` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/3/builds/5226

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

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
...
10.105 [34/18/26] Linking CXX executable unittests/DebugInfo/Symbolizer/DebugInfoSymbolizerTests
10.181 [33/18/27] Linking CXX executable unittests/DebugInfo/GSYM/DebugInfoGSYMTests
10.370 [32/18/28] Linking CXX executable unittests/DWARFLinkerParallel/DWARFLinkerParallelTests
10.622 [31/18/29] Linking CXX executable unittests/Debuginfod/DebuginfodTests
10.831 [30/18/30] Linking CXX executable unittests/DebugInfo/PDB/DebugInfoPDBTests
11.319 [29/18/31] Linking CXX executable unittests/ExecutionEngine/ExecutionEngineTests
11.450 [28/18/32] Linking CXX executable unittests/DebugInfo/LogicalView/DebugInfoLogicalViewTests
11.495 [27/18/33] Linking CXX executable unittests/ExecutionEngine/JITLink/JITLinkTests
11.892 [26/18/34] Linking CXX executable unittests/InterfaceStub/InterfaceStubTests
12.089 [25/18/35] Building CXX object unittests/Analysis/CMakeFiles/AnalysisTests.dir/SparsePropagation.cpp.o
FAILED: unittests/Analysis/CMakeFiles/AnalysisTests.dir/SparsePropagation.cpp.o 
/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 -Iunittests/Analysis -I/buildbot/worker/arc-folder/llvm-project/llvm/unittests/Analysis -Iinclude -I/buildbot/worker/arc-folder/llvm-project/llvm/include -I/buildbot/worker/arc-folder/llvm-project/third-party/unittest/googletest/include -I/buildbot/worker/arc-folder/llvm-project/third-party/unittest/googlemock/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -fno-lifetime-dse -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 -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG  -Wno-variadic-macros -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -Wno-suggest-override -std=c++17 -MD -MT unittests/Analysis/CMakeFiles/AnalysisTests.dir/SparsePropagation.cpp.o -MF unittests/Analysis/CMakeFiles/AnalysisTests.dir/SparsePropagation.cpp.o.d -o unittests/Analysis/CMakeFiles/AnalysisTests.dir/SparsePropagation.cpp.o -c /buildbot/worker/arc-folder/llvm-project/llvm/unittests/Analysis/SparsePropagation.cpp
/buildbot/worker/arc-folder/llvm-project/llvm/unittests/Analysis/SparsePropagation.cpp:141:8: error: 'void {anonymous}::TestLatticeFunc::ComputeInstructionState(llvm::Instruction&, llvm::DenseMap<llvm::PointerIntPair<llvm::Value*, 2, {anonymous}::IPOGrouping>, {anonymous}::TestLatticeVal>&, llvm::SparseSolver<llvm::PointerIntPair<llvm::Value*, 2, {anonymous}::IPOGrouping>, {anonymous}::TestLatticeVal, llvm::LatticeKeyInfo<llvm::PointerIntPair<llvm::Value*, 2, {anonymous}::IPOGrouping> > >&)' marked 'override', but does not override
  141 |   void ComputeInstructionState(
      |        ^~~~~~~~~~~~~~~~~~~~~~~
/buildbot/worker/arc-folder/llvm-project/llvm/unittests/Analysis/SparsePropagation.cpp:230:19: error: cannot declare field '{anonymous}::SparsePropagationTest::Lattice' to be of abstract type '{anonymous}::TestLatticeFunc'
  230 |   TestLatticeFunc Lattice;
      |                   ^~~~~~~
/buildbot/worker/arc-folder/llvm-project/llvm/unittests/Analysis/SparsePropagation.cpp:98:7: note:   because the following virtual functions are pure within '{anonymous}::TestLatticeFunc':
   98 | class TestLatticeFunc
      |       ^~~~~~~~~~~~~~~
In file included from /buildbot/worker/arc-folder/llvm-project/llvm/unittests/Analysis/SparsePropagation.cpp:9:
/buildbot/worker/arc-folder/llvm-project/llvm/include/llvm/Analysis/SparsePropagation.h:90:16: note:     'void llvm::AbstractLatticeFunction<LatticeKey, LatticeVal>::ComputeInstructionState(llvm::Instruction&, llvm::SmallDenseMap<LatticeKey, LatticeVal, 16>&, llvm::SparseSolver<LatticeKey, LatticeVal>&) [with LatticeKey = llvm::PointerIntPair<llvm::Value*, 2, {anonymous}::IPOGrouping>; LatticeVal = {anonymous}::TestLatticeVal]'
   90 |   virtual void ComputeInstructionState(
      |                ^~~~~~~~~~~~~~~~~~~~~~~
12.089 [25/17/36] Linking CXX executable tools/clang/unittests/CodeGen/ClangCodeGenTests
12.797 [25/16/37] Linking CXX executable unittests/Linker/LinkerTests
12.809 [25/15/38] Linking CXX executable unittests/FuzzMutate/FuzzMutateTests
13.072 [25/14/39] Linking CXX executable unittests/CodeGen/GlobalISel/GlobalISelTests
13.238 [25/13/40] Linking CXX executable tools/clang/unittests/Tooling/ToolingTests
13.609 [25/12/41] Linking CXX executable unittests/DebugInfo/DWARF/DebugInfoDWARFTests
13.683 [25/11/42] Linking CXX executable tools/clang/unittests/Index/IndexTests
13.743 [25/10/43] Linking CXX executable tools/clang/unittests/Support/ClangSupportTests
13.804 [25/9/44] Linking CXX executable tools/clang/unittests/Serialization/SerializationTests
14.125 [25/8/45] Linking CXX executable unittests/CodeGen/CodeGenTests
14.682 [25/7/46] Linking CXX executable tools/clang/unittests/Frontend/FrontendTests
14.694 [25/6/47] Linking CXX executable unittests/Frontend/LLVMFrontendTests
15.562 [25/5/48] Linking CXX executable unittests/ExecutionEngine/Orc/OrcJITTests
16.295 [25/4/49] Linking CXX executable unittests/IR/IRTests
16.364 [25/3/50] Linking CXX executable unittests/ExecutionEngine/MCJIT/MCJITTests
20.152 [25/2/51] Linking CXX executable tools/clang/unittests/Interpreter/ExceptionTests/ClangReplInterpreterExceptionTests
20.287 [25/1/52] Linking CXX executable tools/clang/unittests/Interpreter/ClangReplInterpreterTests
ninja: build stopped: subcommand failed.

```

</details>

https://github.com/llvm/llvm-project/pull/109417