[InstCombine][NFC] Rename check run label

[piotr]

Summary

The existing check run label "DEFAULT" may clash with
the label from switch "DEFAULT", so renaming it for clarity.

[piotr]

Note: I am aware the "DEFAULT" prefix is currently unused, but was not sure if the intention was for it to be used in the near future - so I am leaving it there for now.

[nikic]

The existing check run label "DEFAULT" may clash with
the label from switch "DEFAULT", so renaming it for clarity.

Not sure I understand the clash. The check-prefixes and the variable names shouldn't clash, right?

[piotr]

llvm/test/Transforms/InstCombine/unreachable-code.ll

146

Part of this line contains a substring that could potentially be matched with the check run line "DEFAULT:".

[nikic]

LGTM -- The described file check behavior seems very weird to me, but changing the prefix doesn't hurt either.

llvm/test/Transforms/InstCombine/unreachable-code.ll

146

Is that intentional FileCheck behavior rather than a bug? It seems pretty odd to me that a check prefix would get matched inside a placeholder declaration of a different check prefix.

[piotr]

llvm/test/Transforms/InstCombine/unreachable-code.ll

146

Not sure - I was surprised to see this failing too. Maybe --match-full-lines would've avoided the failure, although I didn't check.

llvm/test/Transforms/InstCombine/unreachable-code.ll

 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 2
-; RUN: opt -S -passes=instcombine -instcombine-infinite-loop-threshold=2 < %s | FileCheck %s --check-prefixes=CHECK,DEFAULT
+; RUN: opt -S -passes=instcombine -instcombine-infinite-loop-threshold=2 < %s | FileCheck %s --check-prefixes=CHECK,DEFAULT_ITER
 ; RUN: opt -S -passes='instcombine<max-iterations=1>' < %s | FileCheck %s --check-prefixes=CHECK,MAX1
 
 declare void @dummy()
 
 define i32 @br_true(i1 %x) {
 ; CHECK-LABEL: define i32 @br_true
 ; CHECK-SAME: (i1 [[X:%.*]]) {
 ; CHECK-NEXT:    br i1 true, label [[IF:%.*]], label [[ELSE:%.*]]

 default:
   call void @dummy()
   ret void
 }
 
 define void @switch_default(i32 %x) {
 ; CHECK-LABEL: define void @switch_default
 ; CHECK-SAME: (i32 [[X:%.*]]) {
 ; CHECK-NEXT:    switch i32 -1, label [[DEFAULT:%.*]] [
 ; CHECK-NEXT:    i32 0, label [[CASE0:%.*]]
 ; CHECK-NEXT:    ]
 ; CHECK:       case0:
 ; CHECK-NEXT:    ret void
 ; CHECK:       default:
 ; CHECK-NEXT:    call void @dummy()
 ; CHECK-NEXT:    ret void
 ;
loop:
   call void @dummy()
   br label %loop
 
 exit:
   call void @dummy()
   ret void
 }
 ;; NOTE: These prefixes are unused and the list is autogenerated. Do not add tests below this line:
-; DEFAULT: {{.*}}
+; DEFAULT_ITER: {{.*}}
 ; MAX1: {{.*}}