diff --git a/clang/include/clang/Basic/Builtins.def b/clang/include/clang/Basic/Builtins.def
--- a/clang/include/clang/Basic/Builtins.def
+++ b/clang/include/clang/Basic/Builtins.def
@@ -560,7 +560,7 @@
 BUILTIN(__builtin_stdarg_start, "vA.", "nt")
 BUILTIN(__builtin_assume_aligned, "v*vC*z.", "nctE")
 BUILTIN(__builtin_bcmp, "ivC*vC*z", "FnE")
-BUILTIN(__builtin_bcopy, "vv*v*z", "n")
+BUILTIN(__builtin_bcopy, "vvC*v*z", "nF")
 BUILTIN(__builtin_bzero, "vv*z", "nF")
 BUILTIN(__builtin_free, "vv*", "nF")
 BUILTIN(__builtin_malloc, "v*z", "nF")
@@ -1156,6 +1156,7 @@
 LIBBUILTIN(index, "c*cC*i",       "f",     STRINGS_H, ALL_GNU_LANGUAGES)
 LIBBUILTIN(rindex, "c*cC*i",      "f",     STRINGS_H, ALL_GNU_LANGUAGES)
 LIBBUILTIN(bzero, "vv*z",         "f",     STRINGS_H, ALL_GNU_LANGUAGES)
+LIBBUILTIN(bcopy, "vvC*v*z",      "f",     STRINGS_H, ALL_GNU_LANGUAGES)
 LIBBUILTIN(bcmp, "ivC*vC*z",      "fE",    STRINGS_H, ALL_GNU_LANGUAGES)
 // In some systems str[n]casejmp is a macro that expands to _str[n]icmp.
 // We undefine then here to avoid wrong name.
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -4356,6 +4356,10 @@
   case Builtin::BIbzero:
     return Builtin::BIbzero;
 
+  case Builtin::BI__builtin_bcopy:
+  case Builtin::BIbcopy:
+    return Builtin::BIbcopy;
+
   case Builtin::BIfree:
     return Builtin::BIfree;
 
@@ -4387,6 +4391,8 @@
         return Builtin::BIstrlen;
       if (FnInfo->isStr("bzero"))
         return Builtin::BIbzero;
+      if (FnInfo->isStr("bcopy"))
+        return Builtin::BIbcopy;
     } else if (isInStdNamespace()) {
       if (FnInfo->isStr("free"))
         return Builtin::BIfree;
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -3618,6 +3618,20 @@
     Builder.CreateMemSet(Dest, Builder.getInt8(0), SizeVal, false);
     return RValue::get(nullptr);
   }
+
+  case Builtin::BIbcopy:
+  case Builtin::BI__builtin_bcopy: {
+    Address Src = EmitPointerWithAlignment(E->getArg(0));
+    Address Dest = EmitPointerWithAlignment(E->getArg(1));
+    Value *SizeVal = EmitScalarExpr(E->getArg(2));
+    EmitNonNullArgCheck(RValue::get(Src.getPointer()), E->getArg(0)->getType(),
+                        E->getArg(0)->getExprLoc(), FD, 0);
+    EmitNonNullArgCheck(RValue::get(Dest.getPointer()), E->getArg(1)->getType(),
+			E->getArg(1)->getExprLoc(), FD, 1);
+    Builder.CreateMemMove(Dest, Src, SizeVal, false);
+    return RValue::get(Dest.getPointer());
+  }
+
   case Builtin::BImemcpy:
   case Builtin::BI__builtin_memcpy:
   case Builtin::BImempcpy:
diff --git a/clang/test/Analysis/bstring.c b/clang/test/Analysis/bstring.c
--- a/clang/test/Analysis/bstring.c
+++ b/clang/test/Analysis/bstring.c
@@ -483,8 +483,7 @@
 //===----------------------------------------------------------------------===
 
 #define bcopy BUILTIN(bcopy)
-// __builtin_bcopy is not defined with const in Builtins.def.
-void bcopy(/*const*/ void *s1, void *s2, size_t n);
+void bcopy(const void *s1, void *s2, size_t n);
 
 
 void bcopy0 (void) {
diff --git a/clang/test/Analysis/security-syntax-checks.m b/clang/test/Analysis/security-syntax-checks.m
--- a/clang/test/Analysis/security-syntax-checks.m
+++ b/clang/test/Analysis/security-syntax-checks.m
@@ -77,9 +77,9 @@
 }
 
 // Obsolete function bcopy
-void bcopy(void *, void *, size_t);
+void bcopy(const void *, void *, size_t);
 
-void test_bcopy(void *a, void *b, size_t n) {
+void test_bcopy(const void *a, void *b, size_t n) {
   bcopy(a, b, n); // expected-warning{{The bcopy() function is obsoleted by memcpy() or memmove(}}
 }
 
diff --git a/clang/test/CodeGen/PowerPC/builtins-ppc-xlcompat-macros.c b/clang/test/CodeGen/PowerPC/builtins-ppc-xlcompat-macros.c
--- a/clang/test/CodeGen/PowerPC/builtins-ppc-xlcompat-macros.c
+++ b/clang/test/CodeGen/PowerPC/builtins-ppc-xlcompat-macros.c
@@ -167,15 +167,15 @@
 }
 
 // 64BIT-LABEL: @testbcopy(
-// 64BIT:         call void @bcopy(ptr noundef {{%.*}}, ptr noundef {{%.*}}, i64 noundef {{%.*}})
+// 64BIT:         call void @llvm.memmove.p0.p0.i64(ptr align 1 {{%.*}}, ptr align 1 {{%.*}}, i64 {{%.*}}, i1 false)
 // 64BIT-NEXT:    ret void
 //
 // 32BIT-LABEL: @testbcopy(
-// 32BIT:         call void @bcopy(ptr noundef {{%.*}}, ptr noundef {{%.*}}, i32 noundef {{%.*}})
+// 32BIT:         call void @llvm.memmove.p0.p0.i32(ptr align 1 {{%.*}}, ptr align 1 {{%.*}}, i32 {{%.*}}, i1 false)
 // 32BIT-NEXT:    ret void
 //
 void testbcopy(const void *src, void *dest, size_t n) {
-  __bcopy(src, dest, n);
+  bcopy(src, dest, n);
 }
 
 // 64BIT-LABEL: @testbzero(