diff --git a/cc/config/arm64_device.go b/cc/config/arm64_device.go
index bcff775ab..6a6382841 100644
--- a/cc/config/arm64_device.go
+++ b/cc/config/arm64_device.go
@@ -25,11 +25,6 @@ var (
 	arm64Cflags = []string{
 		// Help catch common 32/64-bit errors.
 		"-Werror=implicit-function-declaration",
-
-		// Prevent use of x18 register.
-		// TODO(pcc): Remove this flag once we upgrade past LLVM r340889
-		// which does this by default on Android.
-		"-ffixed-x18",
 	}
 
 	arm64ArchVariantCflags = map[string][]string{
diff --git a/cc/lto.go b/cc/lto.go
index d9d2662af..52b9a34d2 100644
--- a/cc/lto.go
+++ b/cc/lto.go
@@ -113,13 +113,6 @@ func (lto *lto) flags(ctx BaseModuleContext, flags Flags) Flags {
 			flags.LdFlags = append(flags.LdFlags, "-Wl,-plugin-opt,-inline-threshold=0")
 			flags.LdFlags = append(flags.LdFlags, "-Wl,-plugin-opt,-unroll-threshold=0")
 		}
-
-		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")
-		}
 	}
 	return flags
 }
diff --git a/cc/sanitize.go b/cc/sanitize.go
index 527ae334b..330a5e3a7 100644
--- a/cc/sanitize.go
+++ b/cc/sanitize.go
@@ -471,13 +471,6 @@ func (sanitize *sanitize) flags(ctx ModuleContext, flags Flags) Flags {
 			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)