[llvm] Use std::move to avoid copying (PR #116935)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-globalisel

Author: None (abhishek-kaushik22)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/116935.diff


3 Files Affected:

- (modified) llvm/lib/CodeGen/GlobalISel/GISelKnownBits.cpp (+1-1) 
- (modified) llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp (+1-1) 
- (modified) llvm/lib/CodeGen/MIRPrinter.cpp (+3-3) 


``````````diff
diff --git a/llvm/lib/CodeGen/GlobalISel/GISelKnownBits.cpp b/llvm/lib/CodeGen/GlobalISel/GISelKnownBits.cpp
index a700d866afa4ec..827da6a2ed8098 100644
--- a/llvm/lib/CodeGen/GlobalISel/GISelKnownBits.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/GISelKnownBits.cpp
@@ -537,7 +537,7 @@ void GISelKnownBits::computeKnownBitsImpl(Register R, KnownBits &Known,
     computeKnownBitsImpl(SrcReg, SrcOpKnown, SubDemandedElts, Depth + 1);
 
     if (SrcTy.isVector())
-      Known = SrcOpKnown;
+      Known = std::move(SrcOpKnown);
     else
       Known = SrcOpKnown.extractBits(BitWidth, BitWidth * DstIdx);
     break;
diff --git a/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp b/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp
index a9d28a39c4418b..748dd0ca9858e0 100644
--- a/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp
+++ b/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp
@@ -2927,7 +2927,7 @@ std::optional<ValueIDNum> InstrRefBasedLDV::pickOperandPHILoc(
     SmallVector<LocIdx, 4> NewCandidates;
     std::set_intersection(CandidateLocs.begin(), CandidateLocs.end(),
                           LocVec.begin(), LocVec.end(), std::inserter(NewCandidates, NewCandidates.begin()));
-    CandidateLocs = NewCandidates;
+    CandidateLocs = std::move(NewCandidates);
   }
   if (CandidateLocs.empty())
     return std::nullopt;
diff --git a/llvm/lib/CodeGen/MIRPrinter.cpp b/llvm/lib/CodeGen/MIRPrinter.cpp
index 658bbe0e577e5c..398f2934940f59 100644
--- a/llvm/lib/CodeGen/MIRPrinter.cpp
+++ b/llvm/lib/CodeGen/MIRPrinter.cpp
@@ -345,7 +345,7 @@ void MIRPrinter::convert(yaml::MachineFunction &YamlMF,
     if (PreferredReg)
       printRegMIR(PreferredReg, VReg.PreferredRegister, TRI);
     printRegFlags(Reg, VReg.RegisterFlags, MF, TRI);
-    YamlMF.VirtualRegisters.push_back(VReg);
+    YamlMF.VirtualRegisters.push_back(std::move(VReg));
   }
 
   // Print the live ins.
@@ -354,7 +354,7 @@ void MIRPrinter::convert(yaml::MachineFunction &YamlMF,
     printRegMIR(LI.first, LiveIn.Register, TRI);
     if (LI.second)
       printRegMIR(LI.second, LiveIn.VirtualRegister, TRI);
-    YamlMF.LiveIns.push_back(LiveIn);
+    YamlMF.LiveIns.push_back(std::move(LiveIn));
   }
 
   // Prints the callee saved registers.
@@ -364,7 +364,7 @@ void MIRPrinter::convert(yaml::MachineFunction &YamlMF,
     for (const MCPhysReg *I = CalleeSavedRegs; *I; ++I) {
       yaml::FlowStringValue Reg;
       printRegMIR(*I, Reg, TRI);
-      CalleeSavedRegisters.push_back(Reg);
+      CalleeSavedRegisters.push_back(std::move(Reg));
     }
     YamlMF.CalleeSavedRegisters = CalleeSavedRegisters;
   }

``````````

</details>


https://github.com/llvm/llvm-project/pull/116935