Add RCPC ISA detection on win-arm64 (#82527)

* Add RCPC ISA detection on win-arm64

* Address feedback

Author: EgorBo

src/coreclr/nativeaot/Runtime/windows/PalRedhawkMinWin.cpp

@@ -761,6 +761,18 @@ REDHAWK_PALIMPORT void REDHAWK_PALAPI PAL_GetCpuCapabilityFlags(int* flags)
 {
     *flags = 0;
 
+// Older version of SDK would return false for these intrinsics
+// but make sure we pass the right values to the APIs
+#ifndef PF_ARM_V81_ATOMIC_INSTRUCTIONS_AVAILABLE
+#define PF_ARM_V81_ATOMIC_INSTRUCTIONS_AVAILABLE 34
+#endif
+#ifndef PF_ARM_V82_DP_INSTRUCTIONS_AVAILABLE
+#define PF_ARM_V82_DP_INSTRUCTIONS_AVAILABLE 43
+#endif
+#ifndef PF_ARM_V83_LRCPC_INSTRUCTIONS_AVAILABLE
+#define PF_ARM_V83_LRCPC_INSTRUCTIONS_AVAILABLE 45
+#endif
+
     // FP and SIMD support are enabled by default
     *flags |= ARM64IntrinsicConstants_AdvSimd;
 
@@ -780,6 +792,16 @@ REDHAWK_PALIMPORT void REDHAWK_PALAPI PAL_GetCpuCapabilityFlags(int* flags)
     {
         *flags |= ARM64IntrinsicConstants_Atomics;
     }
+
+    if (IsProcessorFeaturePresent(PF_ARM_V82_DP_INSTRUCTIONS_AVAILABLE))
+    {
+        *flags |= ARM64IntrinsicConstants_Dp;
+    }
+
+    if (IsProcessorFeaturePresent(PF_ARM_V83_LRCPC_INSTRUCTIONS_AVAILABLE))
+    {
+        *flags |= ARM64IntrinsicConstants_Rcpc;
+    }
 }
 
 #endif

src/coreclr/vm/codeman.cpp

@@ -1656,7 +1656,10 @@ void EEJitManager::SetCpuInfo()
 #define PF_ARM_V81_ATOMIC_INSTRUCTIONS_AVAILABLE 34
 #endif
 #ifndef PF_ARM_V82_DP_INSTRUCTIONS_AVAILABLE
-# define PF_ARM_V82_DP_INSTRUCTIONS_AVAILABLE 43
+#define PF_ARM_V82_DP_INSTRUCTIONS_AVAILABLE 43
+#endif
+#ifndef PF_ARM_V83_LRCPC_INSTRUCTIONS_AVAILABLE
+#define PF_ARM_V83_LRCPC_INSTRUCTIONS_AVAILABLE 45
 #endif
 
     // PF_ARM_V81_ATOMIC_INSTRUCTIONS_AVAILABLE (34)
@@ -1671,6 +1674,12 @@ void EEJitManager::SetCpuInfo()
         CPUCompileFlags.Set(InstructionSet_Dp);
     }
 
+    // PF_ARM_V83_LRCPC_INSTRUCTIONS_AVAILABLE (45)
+    if (IsProcessorFeaturePresent(PF_ARM_V83_LRCPC_INSTRUCTIONS_AVAILABLE))
+    {
+        CPUCompileFlags.Set(InstructionSet_Rcpc);
+    }
+
 #endif // HOST_64BIT
     if (GetDataCacheZeroIDReg() == 4)
     {