MachineIRBuilder: Rename buildMerge. NFC

`buildMerge` may build a G_MERGE_VALUES, G_BUILD_VECTOR or
G_CONCAT_VECTORS. Rename it to `buildMergeLikeInstr`.

This is a follow-up suggested in https://reviews.llvm.org/D140964

Differential Revision: https://reviews.llvm.org/D141372
diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index e21de08..8a1fce2 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -235,7 +235,7 @@
   // Requested sub-vectors of NarrowTy.
   for (unsigned i = 0; i < NumNarrowTyPieces; ++i, Offset += NumElts) {
     ArrayRef<Register> Pieces(&Elts[Offset], NumElts);
-    VRegs.push_back(MIRBuilder.buildMerge(NarrowTy, Pieces).getReg(0));
+    VRegs.push_back(MIRBuilder.buildMergeLikeInstr(NarrowTy, Pieces).getReg(0));
   }
 
   // Leftover element(s).
@@ -244,7 +244,8 @@
   } else {
     LLT LeftoverTy = LLT::fixed_vector(LeftoverNumElts, EltTy);
     ArrayRef<Register> Pieces(&Elts[Offset], LeftoverNumElts);
-    VRegs.push_back(MIRBuilder.buildMerge(LeftoverTy, Pieces).getReg(0));
+    VRegs.push_back(
+        MIRBuilder.buildMergeLikeInstr(LeftoverTy, Pieces).getReg(0));
   }
 }
 
@@ -257,7 +258,7 @@
     assert(LeftoverRegs.empty());
 
     if (!ResultTy.isVector()) {
-      MIRBuilder.buildMerge(DstReg, PartRegs);
+      MIRBuilder.buildMergeLikeInstr(DstReg, PartRegs);
       return;
     }
 
@@ -306,7 +307,7 @@
   else
     appendVectorElts(AllElts, Leftover);
 
-  MIRBuilder.buildMerge(DstReg, AllElts);
+  MIRBuilder.buildMergeLikeInstr(DstReg, AllElts);
 }
 
 /// Append the result registers of G_UNMERGE_VALUES \p MI to \p Regs.
@@ -423,7 +424,7 @@
     if (NumSubParts == 1)
       Remerge[I] = SubMerge[0];
     else
-      Remerge[I] = MIRBuilder.buildMerge(NarrowTy, SubMerge).getReg(0);
+      Remerge[I] = MIRBuilder.buildMergeLikeInstr(NarrowTy, SubMerge).getReg(0);
 
     // In the sign extend padding case, re-use the first all-signbit merge.
     if (AllMergePartsArePadding && !AllPadReg)
@@ -442,11 +443,11 @@
   // the result.
 
   if (DstTy == LCMTy) {
-    MIRBuilder.buildMerge(DstReg, RemergeRegs);
+    MIRBuilder.buildMergeLikeInstr(DstReg, RemergeRegs);
     return;
   }
 
-  auto Remerge = MIRBuilder.buildMerge(LCMTy, RemergeRegs);
+  auto Remerge = MIRBuilder.buildMergeLikeInstr(LCMTy, RemergeRegs);
   if (DstTy.isScalar() && LCMTy.isScalar()) {
     MIRBuilder.buildTrunc(DstReg, Remerge);
     return;
@@ -460,7 +461,7 @@
       UnmergeDefs[I] = MRI.createGenericVirtualRegister(DstTy);
 
     MIRBuilder.buildUnmerge(UnmergeDefs,
-                            MIRBuilder.buildMerge(LCMTy, RemergeRegs));
+                            MIRBuilder.buildMergeLikeInstr(LCMTy, RemergeRegs));
     return;
   }
 
@@ -941,7 +942,7 @@
     if (DstTy.isVector())
       MIRBuilder.buildBuildVector(DstReg, DstRegs);
     else
-      MIRBuilder.buildMerge(DstReg, DstRegs);
+      MIRBuilder.buildMergeLikeInstr(DstReg, DstRegs);
     MI.eraseFromParent();
     return Legalized;
   }
@@ -1013,7 +1014,7 @@
           MIRBuilder.buildFreeze(NarrowTy, Unmerge.getReg(i)).getReg(0));
     }
 
-    MIRBuilder.buildMerge(MI.getOperand(0).getReg(), Parts);
+    MIRBuilder.buildMergeLikeInstr(MI.getOperand(0).getReg(), Parts);
     MI.eraseFromParent();
     return Legalized;
   }
@@ -1188,7 +1189,7 @@
         MIB.addUse(SrcRegs[j / 2][i]).add(MI.getOperand(j + 1));
     }
     MIRBuilder.setInsertPt(MBB, MBB.getFirstNonPHI());
-    MIRBuilder.buildMerge(MI.getOperand(0), DstRegs);
+    MIRBuilder.buildMergeLikeInstr(MI.getOperand(0), DstRegs);
     Observer.changedInstr(MI);
     MI.eraseFromParent();
     return Legalized;
@@ -1365,7 +1366,7 @@
 
     // Gather the destination registers into the final destination.
     Register DstReg = MI.getOperand(0).getReg();
-    MIRBuilder.buildMerge(DstReg, DstRegs);
+    MIRBuilder.buildMergeLikeInstr(DstReg, DstRegs);
     MI.eraseFromParent();
     return Legalized;
   }
@@ -1385,7 +1386,7 @@
       DstRegs.push_back(DstPart.getReg(0));
     }
 
-    MIRBuilder.buildMerge(MI.getOperand(0), DstRegs);
+    MIRBuilder.buildMergeLikeInstr(MI.getOperand(0), DstRegs);
 
     Observer.changedInstr(MI);
     MI.eraseFromParent();
@@ -1602,16 +1603,17 @@
   // Build merges of each piece.
   ArrayRef<Register> Slicer(Unmerges);
   for (int I = 0; I != NumMerge; ++I, Slicer = Slicer.drop_front(PartsPerGCD)) {
-    auto Merge = MIRBuilder.buildMerge(WideTy, Slicer.take_front(PartsPerGCD));
+    auto Merge =
+        MIRBuilder.buildMergeLikeInstr(WideTy, Slicer.take_front(PartsPerGCD));
     NewMergeRegs.push_back(Merge.getReg(0));
   }
 
   // A truncate may be necessary if the requested type doesn't evenly divide the
   // original result type.
   if (DstTy.getSizeInBits() == WideDstTy.getSizeInBits()) {
-    MIRBuilder.buildMerge(DstReg, NewMergeRegs);
+    MIRBuilder.buildMergeLikeInstr(DstReg, NewMergeRegs);
   } else {
-    auto FinalMerge = MIRBuilder.buildMerge(WideDstTy, NewMergeRegs);
+    auto FinalMerge = MIRBuilder.buildMergeLikeInstr(WideDstTy, NewMergeRegs);
     MIRBuilder.buildTrunc(DstReg, FinalMerge.getReg(0));
   }
 
@@ -1739,7 +1741,7 @@
         RemergeParts.emplace_back(Parts[Idx]);
       }
 
-      MIRBuilder.buildMerge(MI.getOperand(I).getReg(), RemergeParts);
+      MIRBuilder.buildMergeLikeInstr(MI.getOperand(I).getReg(), RemergeParts);
       RemergeParts.clear();
     }
   }
@@ -2680,7 +2682,7 @@
     } else
       getUnmergePieces(SrcRegs, MIRBuilder, Src, SrcEltTy);
 
-    MIRBuilder.buildMerge(Dst, SrcRegs);
+    MIRBuilder.buildMergeLikeInstr(Dst, SrcRegs);
     MI.eraseFromParent();
     return Legalized;
   }
@@ -2688,7 +2690,7 @@
   if (DstTy.isVector()) {
     SmallVector<Register, 8> SrcRegs;
     getUnmergePieces(SrcRegs, MIRBuilder, Src, DstTy.getElementType());
-    MIRBuilder.buildMerge(Dst, SrcRegs);
+    MIRBuilder.buildMergeLikeInstr(Dst, SrcRegs);
     MI.eraseFromParent();
     return Legalized;
   }
@@ -3760,7 +3762,7 @@
       mergeMixedSubvectors(MI.getReg(i), OutputRegs[i]);
   } else {
     for (unsigned i = 0; i < NumDefs; ++i)
-      MIRBuilder.buildMerge(MI.getReg(i), OutputRegs[i]);
+      MIRBuilder.buildMergeLikeInstr(MI.getReg(i), OutputRegs[i]);
   }
 
   MI.eraseFromParent();
@@ -3808,7 +3810,7 @@
   if (NumLeftovers) {
     mergeMixedSubvectors(MI.getReg(0), OutputRegs);
   } else {
-    MIRBuilder.buildMerge(MI.getReg(0), OutputRegs);
+    MIRBuilder.buildMergeLikeInstr(MI.getReg(0), OutputRegs);
   }
 
   MI.eraseFromParent();
@@ -3911,10 +3913,11 @@
     for (unsigned i = 0, Offset = 0; i < NumNarrowTyPieces;
          ++i, Offset += NumNarrowTyElts) {
       ArrayRef<Register> Pieces(&Elts[Offset], NumNarrowTyElts);
-      NarrowTyElts.push_back(MIRBuilder.buildMerge(NarrowTy, Pieces).getReg(0));
+      NarrowTyElts.push_back(
+          MIRBuilder.buildMergeLikeInstr(NarrowTy, Pieces).getReg(0));
     }
 
-    MIRBuilder.buildMerge(DstReg, NarrowTyElts);
+    MIRBuilder.buildMergeLikeInstr(DstReg, NarrowTyElts);
     MI.eraseFromParent();
     return Legalized;
   }
@@ -3942,10 +3945,11 @@
     SmallVector<Register, 8> Sources;
     for (unsigned j = 0; j < NumElts; ++j)
       Sources.push_back(MI.getOperand(1 + i * NumElts + j).getReg());
-    NarrowTyElts.push_back(MIRBuilder.buildMerge(NarrowTy, Sources).getReg(0));
+    NarrowTyElts.push_back(
+        MIRBuilder.buildMergeLikeInstr(NarrowTy, Sources).getReg(0));
   }
 
-  MIRBuilder.buildMerge(DstReg, NarrowTyElts);
+  MIRBuilder.buildMergeLikeInstr(DstReg, NarrowTyElts);
   MI.eraseFromParent();
   return Legalized;
 }
@@ -4588,7 +4592,7 @@
   MIRBuilder.buildUnmerge({InL, InH}, MI.getOperand(1));
 
   if (Amt.isZero()) {
-    MIRBuilder.buildMerge(MI.getOperand(0), {InL, InH});
+    MIRBuilder.buildMergeLikeInstr(MI.getOperand(0), {InL, InH});
     MI.eraseFromParent();
     return Legalized;
   }
@@ -4661,7 +4665,7 @@
     }
   }
 
-  MIRBuilder.buildMerge(MI.getOperand(0), {Lo, Hi});
+  MIRBuilder.buildMergeLikeInstr(MI.getOperand(0), {Lo, Hi});
   MI.eraseFromParent();
 
   return Legalized;
@@ -4772,7 +4776,7 @@
     llvm_unreachable("not a shift");
   }
 
-  MIRBuilder.buildMerge(DstReg, ResultRegs);
+  MIRBuilder.buildMergeLikeInstr(DstReg, ResultRegs);
   MI.eraseFromParent();
   return Legalized;
 }
@@ -5239,7 +5243,7 @@
 
   // Take only high half of registers if this is high mul.
   ArrayRef<Register> DstRegs(&DstTmpRegs[DstTmpParts - NumParts], NumParts);
-  MIRBuilder.buildMerge(DstReg, DstRegs);
+  MIRBuilder.buildMergeLikeInstr(DstReg, DstRegs);
   MI.eraseFromParent();
   return Legalized;
 }
@@ -5329,7 +5333,7 @@
   if (MRI.getType(DstReg).isVector())
     MIRBuilder.buildBuildVector(DstReg, DstRegs);
   else if (DstRegs.size() > 1)
-    MIRBuilder.buildMerge(DstReg, DstRegs);
+    MIRBuilder.buildMergeLikeInstr(DstReg, DstRegs);
   else
     MIRBuilder.buildCopy(DstReg, DstRegs[0]);
   MI.eraseFromParent();
@@ -5411,10 +5415,10 @@
   Register DstReg = MI.getOperand(0).getReg();
   if (WideSize > RegTy.getSizeInBits()) {
     Register MergeReg = MRI.createGenericVirtualRegister(LLT::scalar(WideSize));
-    MIRBuilder.buildMerge(MergeReg, DstRegs);
+    MIRBuilder.buildMergeLikeInstr(MergeReg, DstRegs);
     MIRBuilder.buildTrunc(DstReg, MergeReg);
   } else
-    MIRBuilder.buildMerge(DstReg, DstRegs);
+    MIRBuilder.buildMergeLikeInstr(DstReg, DstRegs);
 
   MI.eraseFromParent();
   return Legalized;
@@ -6672,7 +6676,7 @@
 
     if (InsertVal) {
       SrcRegs[IdxVal] = MI.getOperand(2).getReg();
-      MIRBuilder.buildMerge(DstReg, SrcRegs);
+      MIRBuilder.buildMergeLikeInstr(DstReg, SrcRegs);
     } else {
       MIRBuilder.buildCopy(DstReg, SrcRegs[IdxVal]);
     }
@@ -6844,7 +6848,7 @@
       if (SubVectorElts.size() == 1)
         MIRBuilder.buildCopy(Dst, SubVectorElts[0]);
       else
-        MIRBuilder.buildMerge(Dst, SubVectorElts);
+        MIRBuilder.buildMergeLikeInstr(Dst, SubVectorElts);
 
       MI.eraseFromParent();
       return Legalized;
@@ -6917,7 +6921,7 @@
         DstElts.push_back(UnmergeSrc.getReg(Idx));
       }
 
-      MIRBuilder.buildMerge(Dst, DstElts);
+      MIRBuilder.buildMergeLikeInstr(Dst, DstElts);
       MI.eraseFromParent();
       return Legalized;
     }