[llvm] [RISCV][TTI] Use processShuffleMask for shuffle legalization estimate (PR #136191)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-x86_64-debian-dylib` running on `gribozavr4` while building `llvm` at step 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/60/builds/25376

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

```
Step 5 (build-unified-tree) failure: build (failure)
...
23.700 [2564/9/4714] Linking CXX static library lib/libLLVMExegesisAArch64.a
23.702 [2564/8/4715] Linking CXX static library lib/libLLVMX86CodeGen.a
23.707 [2563/8/4716] Linking CXX static library lib/libLLVMExegesisX86.a
24.393 [2563/7/4717] Building AMDGPUGenDAGISel.inc...
24.422 [2563/6/4718] Building AMDGPUGenAsmMatcher.inc...
24.998 [2563/5/4719] Building AMDGPUGenInstrInfo.inc...
25.647 [2563/4/4720] Building CXX object lib/LTO/CMakeFiles/LLVMLTO.dir/LTO.cpp.o
25.657 [2562/4/4721] Linking CXX static library lib/libLLVMLTO.a
26.667 [2562/3/4722] Building AMDGPUGenRegisterBank.inc...
27.125 [2562/2/4723] Building CXX object lib/Target/RISCV/CMakeFiles/LLVMRISCVCodeGen.dir/RISCVTargetTransformInfo.cpp.o
FAILED: lib/Target/RISCV/CMakeFiles/LLVMRISCVCodeGen.dir/RISCVTargetTransformInfo.cpp.o 
CCACHE_CPP2=yes CCACHE_HASHDIR=yes /usr/bin/ccache /usr/bin/clang++ -DGTEST_HAS_RTTI=0 -DLLVM_EXPORTS -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/b/1/llvm-x86_64-debian-dylib/build/lib/Target/RISCV -I/b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/lib/Target/RISCV -I/b/1/llvm-x86_64-debian-dylib/build/include -I/b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/include -fPIC -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 -ffunction-sections -fdata-sections -O3 -DNDEBUG -fvisibility=hidden  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -std=c++17 -MD -MT lib/Target/RISCV/CMakeFiles/LLVMRISCVCodeGen.dir/RISCVTargetTransformInfo.cpp.o -MF lib/Target/RISCV/CMakeFiles/LLVMRISCVCodeGen.dir/RISCVTargetTransformInfo.cpp.o.d -o lib/Target/RISCV/CMakeFiles/LLVMRISCVCodeGen.dir/RISCVTargetTransformInfo.cpp.o -c /b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
/b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp:710:11: error: no matching function for call to 'costShuffleViaSplitting'
          costShuffleViaSplitting(*this, LT.second, FVTp, Mask, CostKind);
          ^~~~~~~~~~~~~~~~~~~~~~~
/b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp:392:24: note: candidate function not viable: 1st argument ('const llvm::RISCVTTIImpl') would lose const qualifier
static InstructionCost costShuffleViaSplitting(RISCVTTIImpl &TTI, MVT LegalVT,
                       ^
1 error generated.
28.037 [2562/1/4724] Building AMDGPUGenRegisterInfo.inc...
ninja: build stopped: subcommand failed.

```

</details>

https://github.com/llvm/llvm-project/pull/136191