[AsmPrinter] Avoid repeated hash lookups (NFC) (#127744)

Author: kazutakahirata

llvm/lib/CodeGen/AsmPrinter/EHStreamer.cpp

@@ -252,10 +252,10 @@ void EHStreamer::computeCallSiteTable(
     if (&MBB == &Asm->MF->front() || MBB.isBeginSection()) {
       // We start a call-site range upon function entry and at the beginning of
       // every basic block section.
-      CallSiteRanges.push_back(
-          {Asm->MBBSectionRanges[MBB.getSectionID()].BeginLabel,
-           Asm->MBBSectionRanges[MBB.getSectionID()].EndLabel,
-           Asm->getMBBExceptionSym(MBB), CallSites.size()});
+      auto &Range = Asm->MBBSectionRanges[MBB.getSectionID()];
+      CallSiteRanges.push_back({Range.BeginLabel, Range.EndLabel,
+                                Asm->getMBBExceptionSym(MBB),
+                                CallSites.size()});
       PreviousIsInvoke = false;
       SawPotentiallyThrowing = false;
       LastLabel = nullptr;