[TargetParser] Remove const from a return type (NFC) (#149255)

getHostCPUFeatures constructs and returns a temporary instance of
StringMap<bool>.  We don't need const on the return type.

Author: kazutakahirata

llvm/include/llvm/TargetParser/Host.h

@@ -53,7 +53,7 @@ LLVM_ABI StringRef getHostCPUName();
 /// which features may appear in this map, except that they are all valid LLVM
 /// feature names. The map can be empty, for example if feature detection
 /// fails.
-LLVM_ABI const StringMap<bool, MallocAllocator> getHostCPUFeatures();
+LLVM_ABI StringMap<bool, MallocAllocator> getHostCPUFeatures();
 
 /// This is a function compatible with cl::AddExtraVersionPrinter, which adds
 /// info about the current target triple and detected CPU.

llvm/lib/TargetParser/Host.cpp

@@ -1855,7 +1855,7 @@ VendorSignatures getVendorSignature(unsigned *MaxLeaf) {
 
 #if defined(__i386__) || defined(_M_IX86) || \
     defined(__x86_64__) || defined(_M_X64)
-const StringMap<bool> sys::getHostCPUFeatures() {
+StringMap<bool> sys::getHostCPUFeatures() {
   unsigned EAX = 0, EBX = 0, ECX = 0, EDX = 0;
   unsigned MaxLevel;
   StringMap<bool> Features;
@@ -2068,7 +2068,7 @@ const StringMap<bool> sys::getHostCPUFeatures() {
   return Features;
 }
 #elif defined(__linux__) && (defined(__arm__) || defined(__aarch64__))
-const StringMap<bool> sys::getHostCPUFeatures() {
+StringMap<bool> sys::getHostCPUFeatures() {
   StringMap<bool> Features;
   std::unique_ptr<llvm::MemoryBuffer> P = getProcCpuinfoContent();
   if (!P)
@@ -2148,7 +2148,7 @@ const StringMap<bool> sys::getHostCPUFeatures() {
   return Features;
 }
 #elif defined(_WIN32) && (defined(__aarch64__) || defined(_M_ARM64))
-const StringMap<bool> sys::getHostCPUFeatures() {
+StringMap<bool> sys::getHostCPUFeatures() {
   StringMap<bool> Features;
 
   // If we're asking the OS at runtime, believe what the OS says
@@ -2167,7 +2167,7 @@ const StringMap<bool> sys::getHostCPUFeatures() {
 }
 #elif defined(__linux__) && defined(__loongarch__)
 #include <sys/auxv.h>
-const StringMap<bool> sys::getHostCPUFeatures() {
+StringMap<bool> sys::getHostCPUFeatures() {
   unsigned long hwcap = getauxval(AT_HWCAP);
   bool HasFPU = hwcap & (1UL << 3); // HWCAP_LOONGARCH_FPU
   uint32_t cpucfg2 = 0x2, cpucfg3 = 0x3;
@@ -2196,7 +2196,7 @@ const StringMap<bool> sys::getHostCPUFeatures() {
   return Features;
 }
 #elif defined(__linux__) && defined(__riscv)
-const StringMap<bool> sys::getHostCPUFeatures() {
+StringMap<bool> sys::getHostCPUFeatures() {
   RISCVHwProbe Query[]{{/*RISCV_HWPROBE_KEY_BASE_BEHAVIOR=*/3, 0},
                        {/*RISCV_HWPROBE_KEY_IMA_EXT_0=*/4, 0},
                        {/*RISCV_HWPROBE_KEY_MISALIGNED_SCALAR_PERF=*/9, 0}};
@@ -2279,7 +2279,7 @@ const StringMap<bool> sys::getHostCPUFeatures() {
   return Features;
 }
 #else
-const StringMap<bool> sys::getHostCPUFeatures() { return {}; }
+StringMap<bool> sys::getHostCPUFeatures() { return {}; }
 #endif
 
 #if __APPLE__