[llvm] [BitcodeReader][NFC] Tidy getEnableSplitLTOUnitAndUnifiedFlag (PR #165732)

[Andrew Ng via llvm-commits]

https://github.com/nga888 created https://github.com/llvm/llvm-project/pull/165732

None

>From 7e88bbee6ef4e2ade78507eb3ea6dc79ca56fbd6 Mon Sep 17 00:00:00 2001
From: Andrew Ng <andrew.ng at sony.com>
Date: Wed, 29 Oct 2025 11:34:23 +0000
Subject: [PATCH] [BitcodeReader][NFC] Tidy getEnableSplitLTOUnitAndUnifiedFlag

---
 llvm/lib/Bitcode/Reader/BitcodeReader.cpp | 34 ++++++-----------------
 1 file changed, 9 insertions(+), 25 deletions(-)

diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index 466dcb02696f4..1bdf3e9f684f5 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -8566,16 +8566,13 @@ Expected<std::unique_ptr<ModuleSummaryIndex>> BitcodeModule::getSummary() {
 }
 
 static Expected<std::pair<bool, bool>>
-getEnableSplitLTOUnitAndUnifiedFlag(BitstreamCursor &Stream,
-                                                 unsigned ID,
-                                                 BitcodeLTOInfo &LTOInfo) {
+getEnableSplitLTOUnitAndUnifiedFlag(BitstreamCursor &Stream, unsigned ID) {
   if (Error Err = Stream.EnterSubBlock(ID))
     return std::move(Err);
-  SmallVector<uint64_t, 64> Record;
 
+  SmallVector<uint64_t, 64> Record;
   while (true) {
     BitstreamEntry Entry;
-    std::pair<bool, bool> Result = {false,false};
     if (Error E = Stream.advanceSkippingSubblocks().moveInto(Entry))
       return std::move(E);
 
@@ -8584,8 +8581,8 @@ getEnableSplitLTOUnitAndUnifiedFlag(BitstreamCursor &Stream,
     case BitstreamEntry::Error:
       return error("Malformed block");
     case BitstreamEntry::EndBlock: {
-      // If no flags record found, set both flags to false.
-      return Result;
+      // If no flags record found, return both flags as false.
+      return std::make_pair(false, false);
     }
     case BitstreamEntry::Record:
       // The interesting case.
@@ -8607,9 +8604,7 @@ getEnableSplitLTOUnitAndUnifiedFlag(BitstreamCursor &Stream,
 
       bool EnableSplitLTOUnit = Flags & 0x8;
       bool UnifiedLTO = Flags & 0x200;
-      Result = {EnableSplitLTOUnit, UnifiedLTO};
-
-      return Result;
+      return std::make_pair(EnableSplitLTOUnit, UnifiedLTO);
     }
     }
   }
@@ -8638,26 +8633,15 @@ Expected<BitcodeLTOInfo> BitcodeModule::getLTOInfo() {
                             /*EnableSplitLTOUnit=*/false, /*UnifiedLTO=*/false};
 
     case BitstreamEntry::SubBlock:
-      if (Entry.ID == bitc::GLOBALVAL_SUMMARY_BLOCK_ID) {
-        BitcodeLTOInfo LTOInfo;
+      if (Entry.ID == bitc::GLOBALVAL_SUMMARY_BLOCK_ID ||
+          Entry.ID == bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID) {
         Expected<std::pair<bool, bool>> Flags =
-            getEnableSplitLTOUnitAndUnifiedFlag(Stream, Entry.ID, LTOInfo);
+            getEnableSplitLTOUnitAndUnifiedFlag(Stream, Entry.ID);
         if (!Flags)
           return Flags.takeError();
-        std::tie(LTOInfo.EnableSplitLTOUnit, LTOInfo.UnifiedLTO) = Flags.get();
-        LTOInfo.IsThinLTO = true;
-        LTOInfo.HasSummary = true;
-        return LTOInfo;
-      }
-
-      if (Entry.ID == bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID) {
         BitcodeLTOInfo LTOInfo;
-        Expected<std::pair<bool, bool>> Flags =
-            getEnableSplitLTOUnitAndUnifiedFlag(Stream, Entry.ID, LTOInfo);
-        if (!Flags)
-          return Flags.takeError();
         std::tie(LTOInfo.EnableSplitLTOUnit, LTOInfo.UnifiedLTO) = Flags.get();
-        LTOInfo.IsThinLTO = false;
+        LTOInfo.IsThinLTO = (Entry.ID == bitc::GLOBALVAL_SUMMARY_BLOCK_ID);
         LTOInfo.HasSummary = true;
         return LTOInfo;
       }