Index: clang/include/clang/Basic/TargetInfo.h
===================================================================
--- clang/include/clang/Basic/TargetInfo.h
+++ clang/include/clang/Basic/TargetInfo.h
@@ -210,6 +210,8 @@
 
   unsigned HasAArch64SVETypes : 1;
 
+  unsigned ARMCDECoprocMask : 8;
+
   // TargetInfo Constructor.  Default initializes all fields.
   TargetInfo(const llvm::Triple &T);
 
@@ -808,6 +810,10 @@
   /// available on this target.
   bool hasAArch64SVETypes() const { return HasAArch64SVETypes; }
 
+  /// For ARM targets returns a mask defining which coprocessors are configured
+  /// as Custom Datapath.
+  uint32_t getARMCDECoprocMask() const { return ARMCDECoprocMask; }
+
   /// Returns whether the passed in string is a valid clobber in an
   /// inline asm statement.
   ///
Index: clang/lib/Basic/TargetInfo.cpp
===================================================================
--- clang/lib/Basic/TargetInfo.cpp
+++ clang/lib/Basic/TargetInfo.cpp
@@ -113,6 +113,7 @@
   HasBuiltinMSVaList = false;
   IsRenderScriptTarget = false;
   HasAArch64SVETypes = false;
+  ARMCDECoprocMask = 0;
 
   // Default to no types using fpret.
   RealTypeUsesObjCFPRet = 0;
Index: clang/lib/Basic/Targets/ARM.h
===================================================================
--- clang/lib/Basic/Targets/ARM.h
+++ clang/lib/Basic/Targets/ARM.h
@@ -108,6 +108,7 @@
   bool supportsThumb2() const;
   bool hasMVE() const;
   bool hasMVEFloat() const;
+  bool hasCDE() const;
 
   StringRef getCPUAttr() const;
   StringRef getCPUProfile() const;
Index: clang/lib/Basic/Targets/ARM.cpp
===================================================================
--- clang/lib/Basic/Targets/ARM.cpp
+++ clang/lib/Basic/Targets/ARM.cpp
@@ -154,6 +154,8 @@
   return hasMVE() && (MVE & MVE_FP);
 }
 
+bool ARMTargetInfo::hasCDE() const { return getARMCDECoprocMask() != 0; }
+
 bool ARMTargetInfo::isThumb() const {
   return ArchISA == llvm::ARM::ISAKind::THUMB;
 }
@@ -422,6 +424,7 @@
   HWDiv = 0;
   DotProd = 0;
   HasFloat16 = true;
+  ARMCDECoprocMask = 0;
 
   // This does not diagnose illegal cases like having both
   // "+vfpv2" and "+vfpv3" or having "+neon" and "-fp64".
@@ -486,6 +489,9 @@
       FPU |= FPARMV8;
       MVE |= MVE_INT | MVE_FP;
       HW_FP |= HW_FP_SP | HW_FP_HP;
+    } else if (Feature >= "+cdecp0" && Feature <= "+cdecp7") {
+      unsigned Coproc = Feature.back() - '0';
+      ARMCDECoprocMask |= (1U << Coproc);
     }
   }
 
@@ -758,6 +764,12 @@
     Builder.defineMacro("__ARM_FEATURE_MVE", hasMVEFloat() ? "3" : "1");
   }
 
+  if (hasCDE()) {
+    Builder.defineMacro("__ARM_FEATURE_CDE", "1");
+    Builder.defineMacro("__ARM_FEATURE_CDE_COPROC",
+                        "0x" + Twine::utohexstr(getARMCDECoprocMask()));
+  }
+
   Builder.defineMacro("__ARM_SIZEOF_WCHAR_T",
                       Twine(Opts.WCharSize ? Opts.WCharSize : 4));
 
Index: clang/test/Preprocessor/arm-target-features.c
===================================================================
--- clang/test/Preprocessor/arm-target-features.c
+++ clang/test/Preprocessor/arm-target-features.c
@@ -800,6 +800,18 @@
 // CHECK-V81M-MVE-NODSP-NOT: #define __ARM_FEATURE_MVE
 // CHECK-V81M-MVE-NODSP-NOT: #define __ARM_FEATURE_DSP
 
+// Test CDE (Custom Datapath Extension) feature test macros
+
+// RUN: %clang -target arm-arm-none-eabi -march=armv8m.main -x c -E -dM %s -o - | FileCheck --check-prefix=CHECK-V8M-NOCDE %s
+// CHECK-V8M-NOCDE-NOT: #define __ARM_FEATURE_CDE
+// CHECK-V8M-NOCDE-NOT: #define __ARM_FEATURE_CDE_COPROC
+// RUN: %clang -target arm-arm-none-eabi -march=armv8m.main+cdecp0+cdecp1+cdecp7 -x c -E -dM %s -o - | FileCheck -match-full-lines --check-prefix=CHECK-V8M-CDE-MASK1 %s
+// CHECK-V8M-CDE-MASK1: #define __ARM_FEATURE_CDE 1
+// CHECK-V8M-CDE-MASK1: #define __ARM_FEATURE_CDE_COPROC 0x83
+// RUN: %clang -target arm-arm-none-eabi -march=armv8m.main+cdecp0+cdecp1+cdecp2+cdecp3+cdecp4+cdecp5+cdecp6+cdecp7 -x c -E -dM %s -o - | FileCheck -match-full-lines --check-prefix=CHECK-V8M-CDE-MASK2 %s
+// CHECK-V8M-CDE-MASK2: #define __ARM_FEATURE_CDE 1
+// CHECK-V8M-CDE-MASK2: #define __ARM_FEATURE_CDE_COPROC 0xff
+
 // RUN: %clang -target armv8.1a-none-none-eabi -x c -E -dM %s -o - | FileCheck -match-full-lines --check-prefix=CHECK-V81A %s
 // CHECK-V81A: #define __ARM_ARCH 8
 // CHECK-V81A: #define __ARM_ARCH_8_1A__ 1