[llvm] Reland [AMDGPU] Support block load/store for CSR #130013 (PR #137169)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-ppc64-aix` running on `aix-ppc64` while building `llvm` at step 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/64/builds/3202

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

```
Step 5 (build-unified-tree) failure: build (failure)
...
3142.676 [2014/10/3359] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SILoadStoreOptimizer.cpp.o
3146.836 [2013/10/3360] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SILowerControlFlow.cpp.o
3149.448 [2012/10/3361] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIInsertWaitcnts.cpp.o
3150.808 [2011/10/3362] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SILateBranchLowering.cpp.o
3151.781 [2010/10/3363] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SILowerI1Copies.cpp.o
3156.611 [2009/10/3364] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIInstrInfo.cpp.o
3160.223 [2008/10/3365] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIMachineScheduler.cpp.o
3160.654 [2007/10/3366] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SILowerWWMCopies.cpp.o
3160.798 [2006/10/3367] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIModeRegister.cpp.o
3161.055 [2005/10/3368] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SILowerSGPRSpills.cpp.o
FAILED: lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SILowerSGPRSpills.cpp.o 
/home/llvm/llvm-external-buildbots/clang.19.1.2/bin/clang++ -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_LARGE_FILE_API -D_XOPEN_SOURCE=700 -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/llvm/llvm-external-buildbots/workers/aix-ppc64/clang-ppc64-aix/build/lib/Target/AMDGPU -I/home/llvm/llvm-external-buildbots/workers/aix-ppc64/clang-ppc64-aix/llvm-project/llvm/lib/Target/AMDGPU -I/home/llvm/llvm-external-buildbots/workers/aix-ppc64/clang-ppc64-aix/build/include -I/home/llvm/llvm-external-buildbots/workers/aix-ppc64/clang-ppc64-aix/llvm-project/llvm/include -mcmodel=large -fPIC -Werror -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 -std=c++17  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -pthread -MD -MT lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SILowerSGPRSpills.cpp.o -MF lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SILowerSGPRSpills.cpp.o.d -o lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SILowerSGPRSpills.cpp.o -c /home/llvm/llvm-external-buildbots/workers/aix-ppc64/clang-ppc64-aix/llvm-project/llvm/lib/Target/AMDGPU/SILowerSGPRSpills.cpp
/home/llvm/llvm-external-buildbots/workers/aix-ppc64/clang-ppc64-aix/llvm-project/llvm/lib/Target/AMDGPU/SILowerSGPRSpills.cpp:172:25: error: unused variable 'RI' [-Werror,-Wunused-variable]
  172 |   const SIRegisterInfo *RI = ST.getRegisterInfo();
      |                         ^~
1 error generated.
3161.056 [2005/9/3369] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIModeRegisterDefaults.cpp.o
3163.151 [2005/8/3370] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIMemoryLegalizer.cpp.o
3163.765 [2005/7/3371] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIMachineFunctionInfo.cpp.o
3164.471 [2005/6/3372] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIOptimizeExecMasking.cpp.o
3169.693 [2005/5/3373] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIOptimizeExecMaskingPreRA.cpp.o
3171.316 [2005/4/3374] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIISelLowering.cpp.o
3172.465 [2005/3/3375] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIPostRABundler.cpp.o
3173.400 [2005/2/3376] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIPeepholeSDWA.cpp.o
3183.096 [2005/1/3377] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/SIOptimizeVGPRLiveRange.cpp.o
ninja: build stopped: subcommand failed.

```

</details>

https://github.com/llvm/llvm-project/pull/137169