add comment for test cases

Author: mingmingl-llvm

llvm/test/tools/llvm-profdata/profile-symbol-list-compress.test

@@ -5,6 +5,9 @@ REQUIRES: zlib
 ; RUN: llvm-profdata show -sample -show-prof-sym-list %t.3.output > %t.4.output
 ; RUN: diff -b %S/Inputs/profile-symbol-list.expected %t.4.output
 
+;; Generate two SampleFDO binary profiles and merge them.
+;; Tests that the vtable counters in the merged profile are the aggregated
+;; result from both sources.
 ; RUN: llvm-profdata merge -sample -extbinary -compress-all-sections -extbinary-write-vtable-type-prof -prof-sym-list=%S/Inputs/profile-symbol-list-1.text %S/Inputs/sample-profile-ext.proftext -o %t.1.output
 ; RUN: llvm-profdata merge -sample -extbinary -compress-all-sections -extbinary-write-vtable-type-prof -prof-sym-list=%S/Inputs/profile-symbol-list-2.text %S/Inputs/sample-profile-ext.proftext -o %t.2.output
 ; RUN: llvm-profdata merge -sample -extbinary -compress-all-sections -extbinary-write-vtable-type-prof %t.1.output %t.2.output -o %t.3.output

llvm/test/tools/llvm-profdata/profile-symbol-list.test

@@ -8,6 +8,9 @@
 
 ; NOSYMLIST: ProfileSymbolListSection {{.*}} Size: 0
 
+;; Generate two SampleFDO binary profiles and merge them.
+;; Tests that the vtable counters in the merged profile are the aggregated
+;; result from both sources.
 ; RUN: llvm-profdata merge -sample -extbinary -extbinary-write-vtable-type-prof -prof-sym-list=%S/Inputs/profile-symbol-list-1.text %S/Inputs/sample-profile-ext.proftext -o %t.1.output
 ; RUN: llvm-profdata merge -sample -extbinary -extbinary-write-vtable-type-prof -prof-sym-list=%S/Inputs/profile-symbol-list-2.text %S/Inputs/sample-profile-ext.proftext -o %t.2.output
 ; RUN: llvm-profdata merge -sample -extbinary -extbinary-write-vtable-type-prof %t.1.output %t.2.output -o %t.3.output