[analyzer][NFC] Use switch statement in MallocChecker::performKernelMalloc

Reviewed By: steakhal

Differential Revision: https://reviews.llvm.org/D159397

Author: brad0

clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp

@@ -1141,22 +1141,28 @@ MallocChecker::performKernelMalloc(const CallEvent &Call, CheckerContext &C,
   llvm::Triple::OSType OS = Ctx.getTargetInfo().getTriple().getOS();
 
   if (!KernelZeroFlagVal) {
-    if (OS == llvm::Triple::FreeBSD)
+    switch (OS) {
+    case llvm::Triple::FreeBSD:
       KernelZeroFlagVal = 0x0100;
-    else if (OS == llvm::Triple::NetBSD)
+      break;
+    case llvm::Triple::NetBSD:
       KernelZeroFlagVal = 0x0002;
-    else if (OS == llvm::Triple::OpenBSD)
+      break;
+    case llvm::Triple::OpenBSD:
       KernelZeroFlagVal = 0x0008;
-    else if (OS == llvm::Triple::Linux)
+      break;
+    case llvm::Triple::Linux:
       // __GFP_ZERO
       KernelZeroFlagVal = 0x8000;
-    else
+      break;
+    default:
       // FIXME: We need a more general way of getting the M_ZERO value.
       // See also: O_CREAT in UnixAPIChecker.cpp.
 
       // Fall back to normal malloc behavior on platforms where we don't
       // know M_ZERO.
       return std::nullopt;
+    }
   }
 
   // We treat the last argument as the flags argument, and callers fall-back to