[llvm] [InstCombine] Fold `getelementptr inbounds null, idx -> null` (PR #130742)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

Failed Tests

Clang
Clang.CodeGenOpenCL/spir32_target.cl
Clang.CodeGenOpenCL/spir64_target.cl
Clang.CodeGenOpenCL/spirv_target.cl
LLVM
LLVM.CodeGen/Hexagon/64bit_tstbit.ll
LLVM.CodeGen/Hexagon/always-ext.ll
LLVM.CodeGen/Hexagon/autohvx/isel-concat-multiple.ll
LLVM.CodeGen/Hexagon/autohvx/isel-q-legalization-loop.ll
LLVM.CodeGen/Hexagon/autohvx/vector-align-terminator.ll
LLVM.CodeGen/Hexagon/autohvx/vector-align-use-in-different-block.ll
LLVM.CodeGen/Hexagon/reg-scavengebug-2.ll
LLVM.CodeGen/Hexagon/swp-const-tc1.ll
LLVM.CodeGen/PowerPC/loop-instr-form-non-inc.ll
LLVM.CodeGen/PowerPC/p10-spill-crgt.ll
LLVM.CodeGen/PowerPC/pr43527.ll
LLVM.CodeGen/PowerPC/sms-cpy-1.ll
LLVM.CodeGen/PowerPC/sms-phi.ll
LLVM.Transforms/LoopUnroll/PowerPC/p10-respect-unroll-pragma.ll

https://github.com/llvm/llvm-project/pull/130742