[Bitcode] Use range-based for loops (NFC) (llvm#139421)

Author: kazutakahirata

llvm/lib/Bitcode/Writer/BitcodeWriter.cpp

@@ -2659,9 +2659,9 @@ void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
 
       Record.push_back(VE.getInstructionID(&I));
 
-      for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
-        Record.push_back(MDs[i].first);
-        Record.push_back(VE.getMetadataID(MDs[i].second));
+      for (const auto &[ID, MD] : MDs) {
+        Record.push_back(ID);
+        Record.push_back(VE.getMetadataID(MD));
       }
       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
       Record.clear();

llvm/lib/Bitcode/Writer/ValueEnumerator.cpp

@@ -485,8 +485,8 @@ ValueEnumerator::ValueEnumerator(const Module &M,
         // Enumerate metadata attached with this instruction.
         MDs.clear();
         I.getAllMetadataOtherThanDebugLoc(MDs);
-        for (unsigned i = 0, e = MDs.size(); i != e; ++i)
-          EnumerateMetadata(&F, MDs[i].second);
+        for (const auto &MD : MDs)
+          EnumerateMetadata(&F, MD.second);
 
         // Don't enumerate the location directly -- it has a special record
         // type -- but enumerate its operands.