[ARM] Fix armv6kz LDREX definition (#122965)

Fixes #37901

This behavior is consistent with GCC

Author: Un1q32

clang/lib/Basic/Targets/ARM.cpp

@@ -617,7 +617,8 @@ bool ARMTargetInfo::handleTargetFeatures(std::vector<std::string> &Features,
   case 6:
     if (ArchProfile == llvm::ARM::ProfileKind::M)
       LDREX = 0;
-    else if (ArchKind == llvm::ARM::ArchKind::ARMV6K)
+    else if (ArchKind == llvm::ARM::ArchKind::ARMV6K ||
+             ArchKind == llvm::ARM::ArchKind::ARMV6KZ)
       LDREX = LDREX_D | LDREX_W | LDREX_H | LDREX_B;
     else
       LDREX = LDREX_W;

clang/test/Preprocessor/arm-acle-6.4.c

@@ -93,6 +93,10 @@
 
 // CHECK-V6K: __ARM_FEATURE_LDREX 0xf
 
+// RUN: %clang -target arm-none-linux-eabi -march=armv6kz -x c -E -dM %s -o - | FileCheck %s -check-prefix CHECK-V6KZ
+ 
+// CHECK-V6KZ: __ARM_FEATURE_LDREX 0xf
+
 // RUN: %clang -target arm-none-linux-eabi -march=armv7-a -x c -E -dM %s -o - | FileCheck %s -check-prefix CHECK-V7A
 
 // CHECK-V7A: __ARM_ARCH 7