In https://github.com/llvm/llvm-project/issues/57452, we found that IRTranslator is translating `i1 true` into `i32 -1`.
This is because IRTranslator uses SExt for indices.
In this fix, we change the expected behavior of extractelement's index, moving from SExt to ZExt.
This change includes both documentation, SelectionDAG and IRTranslator.
We also included a test for AMDGPU, updated tests for AArch64, Mips, PowerPC, RISCV, VE, WebAssembly and X86
This patch fixes issue #57452.
Differential Revision: https://reviews.llvm.org/D132978
We do this mostly to be able to test the insert_vector_elt isel
patterns. As long as we don't, most single element insertions show up as
`BUILD_VECTOR` in the backend.
Reviewed By: kaz7
Differential Revision: https://reviews.llvm.org/D93759
