Revert "[llvm-exegesis][AArch64] Disable pauth and ldgm as unsupporte… (#134971)

…d instructions (#132346)"

This reverts commit 559540d as it has
cause build failures in llvm-clang-x86_64-gcc-ubuntu

Author: madhur13490

llvm/test/tools/llvm-exegesis/AArch64/skip_unsupported_instructions.s

@@ -9,58 +9,12 @@
 #include "AArch64.h"
 #include "AArch64RegisterInfo.h"
 
-#ifdef __linux__
-#include <linux/prctl.h> // For PR_PAC_* constants
-#include <sys/prctl.h>
-#endif
-
 #define GET_AVAILABLE_OPCODE_CHECKER
 #include "AArch64GenInstrInfo.inc"
 
 namespace llvm {
 namespace exegesis {
 
-bool isPointerAuth(unsigned Opcode) {
-  switch (Opcode) {
-  default:
-    return false;
-
-  // FIXME: Pointer Authentication instructions.
-  // We would like to measure these instructions, but they can behave
-  // differently on different platforms, and maybe the snippets need to look
-  // different for these instructions,
-  // Platform-specific handling:  On Linux, we disable authentication, may
-  // interfere with measurements. On non-Linux platforms, disable opcodes for
-  // now.
-  case AArch64::AUTDA:
-  case AArch64::AUTDB:
-  case AArch64::AUTDZA:
-  case AArch64::AUTDZB:
-  case AArch64::AUTIA:
-  case AArch64::AUTIA1716:
-  case AArch64::AUTIASP:
-  case AArch64::AUTIAZ:
-  case AArch64::AUTIB:
-  case AArch64::AUTIB1716:
-  case AArch64::AUTIBSP:
-  case AArch64::AUTIBZ:
-  case AArch64::AUTIZA:
-  case AArch64::AUTIZB:
-    return true;
-  }
-}
-
-bool isLoadTagMultiple(unsigned Opcode) {
-  switch (Opcode) {
-  default:
-    return false;
-
-  // Load tag multiple instruction
-  case AArch64::LDGM:
-    return true;
-  }
-}
-
 static unsigned getLoadImmediateOpcode(unsigned RegBitWidth) {
   switch (RegBitWidth) {
   case 32:
@@ -180,35 +134,6 @@ class ExegesisAArch64Target : public ExegesisTarget {
     // Function return is a pseudo-instruction that needs to be expanded
     PM.add(createAArch64ExpandPseudoPass());
   }
-
-  const char *getIgnoredOpcodeReasonOrNull(const LLVMState &State,
-                                           unsigned Opcode) const override {
-    if (const char *Reason =
-            ExegesisTarget::getIgnoredOpcodeReasonOrNull(State, Opcode))
-      return Reason;
-
-    if (isPointerAuth(Opcode)) {
-#ifdef __linux__
-      // Disable all PAC keys. Note that while we expect the measurements to
-      // be the same with PAC keys disabled, they could potentially be lower
-      // since authentication checks are bypassed.
-      if (prctl(PR_PAC_SET_ENABLED_KEYS,
-                PR_PAC_APIAKEY | PR_PAC_APIBKEY | PR_PAC_APDAKEY |
-                    PR_PAC_APDBKEY, // all keys
-                0,                  // disable all
-                0, 0) < 0) {
-        return "Failed to disable PAC keys";
-      }
-#else
-      return "Unsupported opcode: isPointerAuth";
-#endif
-    }
-
-    if (isLoadTagMultiple(Opcode))
-      return "Unsupported opcode: load tag multiple";
-
-    return nullptr;
-  }
 };
 
 } // namespace