[llvm] [LoongArch] use TypeWidenVector for most illegal vector types (PR #126456)

[via llvm-commits]

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@@ -0,0 +1,322 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc --mtriple=loongarch64 --mattr=+lsx %s -o - | FileCheck %s
+
+
+define void @load_sext_2i8_to_2i64(ptr%ptr, ptr%dst) {
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heiher wrote:

It looks like this change was unintentionally lost during a rebase. Could you check?

https://github.com/llvm/llvm-project/pull/126456