diff --git a/llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp b/llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp
--- a/llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp
@@ -745,6 +745,7 @@
     LLVMContext::MD_dereferenceable,
     LLVMContext::MD_dereferenceable_or_null,
     LLVMContext::MD_access_group,
+    LLVMContext::MD_noundef,
   };
 
   for (unsigned ID : KnownIDs)
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -2698,6 +2698,11 @@
       case LLVMContext::MD_preserve_access_index:
         // Preserve !preserve.access.index in K.
         break;
+      case LLVMContext::MD_noundef:
+        // If K does move, keep noundef if it is present in both instructions.
+        if (DoesKMove)
+          K->setMetadata(Kind, JMD);
+        break;
     }
   }
   // Set !invariant.group from J if J has it. If both instructions have it
diff --git a/llvm/test/Transforms/InstCombine/phi-load-metadata-4.ll b/llvm/test/Transforms/InstCombine/phi-load-metadata-4.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/phi-load-metadata-4.ll
@@ -0,0 +1,70 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -passes=instcombine -S < %s | FileCheck %s
+
+declare void @bar()
+declare void @baz()
+
+; Check that !noundef metadata is combined
+define ptr @test_phi_combine_load_metadata(i1 %c, ptr dereferenceable(8) %p1, ptr dereferenceable(8) %p2) {
+; CHECK-LABEL: @test_phi_combine_load_metadata(
+; CHECK-NEXT:    br i1 [[C:%.*]], label [[T:%.*]], label [[F:%.*]]
+; CHECK:       t:
+; CHECK-NEXT:    call void @bar()
+; CHECK-NEXT:    br label [[CONT:%.*]]
+; CHECK:       f:
+; CHECK-NEXT:    call void @baz()
+; CHECK-NEXT:    br label [[CONT]]
+; CHECK:       cont:
+; CHECK-NEXT:    [[RES_IN:%.*]] = phi ptr [ [[P1:%.*]], [[T]] ], [ [[P2:%.*]], [[F]] ]
+; CHECK-NEXT:    [[RES:%.*]] = load ptr, ptr [[RES_IN]], align 8, !noundef !0
+; CHECK-NEXT:    ret ptr [[RES]]
+;
+  br i1 %c, label %t, label %f
+t:
+  call void @bar()
+  %v1 = load ptr, ptr %p1, align 8, !noundef !0
+  br label %cont
+
+f:
+  call void @baz()
+  %v2 = load ptr, ptr %p2, align 8, !noundef !0
+  br label %cont
+
+cont:
+  %res = phi ptr [ %v1, %t ], [ %v2, %f ]
+  ret ptr %res
+}
+
+; Check that !noundef metadata is not combined as a result of
+; there is a load don't have a noundef metadata.
+define ptr @test_phi_combine_load_metadata_negative(i1 %c, ptr dereferenceable(8) %p1, ptr dereferenceable(8) %p2) {
+; CHECK-LABEL: @test_phi_combine_load_metadata_negative(
+; CHECK-NEXT:    br i1 [[C:%.*]], label [[T:%.*]], label [[F:%.*]]
+; CHECK:       t:
+; CHECK-NEXT:    call void @bar()
+; CHECK-NEXT:    br label [[CONT:%.*]]
+; CHECK:       f:
+; CHECK-NEXT:    call void @baz()
+; CHECK-NEXT:    br label [[CONT]]
+; CHECK:       cont:
+; CHECK-NEXT:    [[RES_IN:%.*]] = phi ptr [ [[P1:%.*]], [[T]] ], [ [[P2:%.*]], [[F]] ]
+; CHECK-NEXT:    [[RES:%.*]] = load ptr, ptr [[RES_IN]], align 8
+; CHECK-NEXT:    ret ptr [[RES]]
+;
+  br i1 %c, label %t, label %f
+t:
+  call void @bar()
+  %v1 = load ptr, ptr %p1, align 8, !noundef !0
+  br label %cont
+
+f:
+  call void @baz()
+  %v2 = load ptr, ptr %p2, align 8
+  br label %cont
+
+cont:
+  %res = phi ptr [ %v1, %t ], [ %v2, %f ]
+  ret ptr %res
+}
+
+!0 = !{}