[llvm] [PredicateInfo] Reformat PT_Switch's annotation as valid comments (PR #165249)

[Kunqiu Chen via llvm-commits]

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@@ -133,19 +133,13 @@ define void @test4(i1 %b, i32 %x) {
 ; CHECK-LABEL: @test4(
 ; CHECK-NEXT:    br i1 [[B:%.*]], label [[SW:%.*]], label [[CASE3:%.*]]
 ; CHECK:       sw:
-; CHECK:         i32 0, label [[CASE0:%.*]]
-; CHECK-NEXT:    i32 1, label [[CASE1:%.*]]
-; CHECK-NEXT:    i32 2, label [[CASE0]]
-; CHECK-NEXT:    i32 3, label [[CASE3]]
-; CHECK-NEXT:    i32 4, label [[DEFAULT:%.*]]
-; CHECK-NEXT:    ] Edge: [label [[SW]],label %case1], RenamedOp: [[X:%.*]] }
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Camsyn wrote:

Outputs from -passes=print-predicateinfo consist of TWO parts:
1) Annotation of predicate info as comments
2) no-op bitcasts

The UTC would drop all comments :(
However, it's too annoying to hand-write IR checks for such a big testcase.
Maybe we can add a new feature for UTC to let it check the generated comments? @dtcxzyw 

https://github.com/llvm/llvm-project/pull/165249