[llvm] [RISCV][GISel] Legalizer and register bank selection for G_JUMP_TABLE and G_BRJT (PR #71970)

[Michael Maitland via llvm-commits]

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@@ -0,0 +1,121 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mtriple=riscv32 -mattr=+m -run-pass=legalizer %s -o - \
+# RUN: | FileCheck %s
+
+--- |
+  define i32 @jt_test(i32 %x) {
+  entry:
+    switch i32 %x, label %return [
+      i32 75, label %sw.bb
+      i32 34, label %sw.bb
+      i32 56, label %sw.bb
+      i32 35, label %sw.bb
+      i32 40, label %sw.bb
+      i32 4, label %sw.bb1
+      i32 5, label %sw.bb1
+      i32 6, label %sw.bb1
+    ]
+
+  sw.bb:                                            ; preds = %entry, %entry, %entry, %entry, %entry
+    %add = add nsw i32 %x, 42
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michaelmaitland wrote:

Do we need the `add` and `mul` here? Can we just return? Legalizer and regbank selection will never do any any optimizing of the jump table to the default label if jump targets only contain a branch to the default label.

https://github.com/llvm/llvm-project/pull/71970