diff --git a/llvm/include/llvm/CodeGen/GlobalISel/LegalizerInfo.h b/llvm/include/llvm/CodeGen/GlobalISel/LegalizerInfo.h
--- a/llvm/include/llvm/CodeGen/GlobalISel/LegalizerInfo.h
+++ b/llvm/include/llvm/CodeGen/GlobalISel/LegalizerInfo.h
@@ -113,6 +113,14 @@
     LLT MemoryTy;
     uint64_t AlignInBits;
     AtomicOrdering Ordering;
+
+    MemDesc() = default;
+    MemDesc(LLT MemoryTy, uint64_t AlignInBits, AtomicOrdering Ordering)
+        : MemoryTy(MemoryTy), AlignInBits(AlignInBits), Ordering(Ordering) {}
+    constexpr MemDesc(const MachineMemOperand &MMO)
+        : MemoryTy(MMO.getMemoryType()),
+          AlignInBits(MMO.getAlign().value() * 8),
+          Ordering(MMO.getSuccessOrdering()) {}
   };
 
   /// Operations which require memory can use this to place requirements on the
diff --git a/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
--- a/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
@@ -497,10 +497,7 @@
         continue;
       // Check for legality.
       if (LI) {
-        LegalityQuery::MemDesc MMDesc;
-        MMDesc.MemoryTy = MMO.getMemoryType();
-        MMDesc.AlignInBits = MMO.getAlign().value() * 8;
-        MMDesc.Ordering = MMO.getSuccessOrdering();
+        LegalityQuery::MemDesc MMDesc(MMO);
         LLT UseTy = MRI.getType(UseMI.getOperand(0).getReg());
         LLT SrcTy = MRI.getType(LoadMI->getPointerReg());
         if (LI->getAction({LoadMI->getOpcode(), {UseTy, SrcTy}, {MMDesc}})
@@ -724,10 +721,8 @@
     return false;
 
   const MachineMemOperand &MMO = LoadDef->getMMO();
-  LegalityQuery::MemDesc MMDesc;
+  LegalityQuery::MemDesc MMDesc(MMO);
   MMDesc.MemoryTy = LLT::scalar(NewSizeBits);
-  MMDesc.AlignInBits = MMO.getAlign().value() * 8;
-  MMDesc.Ordering = MMO.getSuccessOrdering();
   if (!isLegalOrBeforeLegalizer({TargetOpcode::G_SEXTLOAD,
                                  {MRI.getType(LoadDef->getDstReg()),
                                   MRI.getType(LoadDef->getPointerReg())},
@@ -3758,10 +3753,8 @@
   // may not use index 0.
   Register Ptr = LowestIdxLoad->getPointerReg();
   const MachineMemOperand &MMO = LowestIdxLoad->getMMO();
-  LegalityQuery::MemDesc MMDesc;
+  LegalityQuery::MemDesc MMDesc(MMO);
   MMDesc.MemoryTy = Ty;
-  MMDesc.AlignInBits = MMO.getAlign().value() * 8;
-  MMDesc.Ordering = MMO.getSuccessOrdering();
   if (!isLegalOrBeforeLegalizer(
           {TargetOpcode::G_LOAD, {Ty, MRI.getType(Ptr)}, {MMDesc}}))
     return false;
diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerInfo.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerInfo.cpp
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerInfo.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerInfo.cpp
@@ -352,8 +352,7 @@
 
   SmallVector<LegalityQuery::MemDesc, 2> MemDescrs;
   for (const auto &MMO : MI.memoperands())
-    MemDescrs.push_back({MMO->getMemoryType(), 8 * MMO->getAlign().value(),
-                         MMO->getSuccessOrdering()});
+    MemDescrs.push_back({*MMO});
 
   return getAction({MI.getOpcode(), Types, MemDescrs});
 }