[clang] [llvm] [LLVM] Add `__builtin_readfixedtimer` intrinsic and buiiltin for realtime clocks (PR #81331)

[Joseph Huber via cfe-commits]

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@@ -312,6 +312,12 @@ void IntrinsicLowering::LowerIntrinsicCall(CallInst *CI) {
     CI->replaceAllUsesWith(ConstantInt::get(Type::getInt64Ty(Context), 0));
     break;
   }
+  case Intrinsic::readfixedtimer: {
+    errs() << "WARNING: this target does not support the llvm.readfixedtimer"
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jhuber6 wrote:

Not that I could tell, but I figured better safe than sorry.

https://github.com/llvm/llvm-project/pull/81331