diff --git a/cc/sanitize.go b/cc/sanitize.go
index 330a5e3..527ae33 100644
--- a/cc/sanitize.go
+++ b/cc/sanitize.go
@@ -471,6 +471,13 @@
 			diagSanitizers = append(diagSanitizers, "cfi")
 		}
 
+		if ctx.Arch().ArchType == android.Arm64 {
+			// Prevent use of x18 register on arm64.
+			// TODO(pcc): Remove this flag once we upgrade past LLVM r340889
+			// which does this by default on Android.
+			flags.LdFlags = append(flags.LdFlags, "-Wl,-plugin-opt,-mattr=+reserve-x18")
+		}
+
 		if ctx.staticBinary() {
 			_, flags.CFlags = removeFromList("-fsanitize-cfi-cross-dso", flags.CFlags)
 			_, flags.LdFlags = removeFromList("-fsanitize-cfi-cross-dso", flags.LdFlags)