diff --git a/gcc/config/aarch64/aarch64-option-extensions.def b/gcc/config/aarch64/aarch64-option-extensions.def
index ca0864220da615566994c41e5f7e250954d9ec90..ec4530179278df9ec2189b52342cc6d57cafc8dd 100644
--- a/gcc/config/aarch64/aarch64-option-extensions.def
+++ b/gcc/config/aarch64/aarch64-option-extensions.def
@@ -226,4 +226,7 @@ AARCH64_OPT_EXTENSION("f64mm", AARCH64_FL_F64MM, \
 AARCH64_OPT_EXTENSION("bf16", AARCH64_FL_BF16, \
 		      AARCH64_FL_SIMD | AARCH64_FL_FP, 0, false, "bf16")
 
+/* Enabling/Disabling "flagm" only changes "flagm".  */
+AARCH64_OPT_EXTENSION("flagm", AARCH64_FL_FLAGM, 0, 0, false, "flagm")
+
 #undef AARCH64_OPT_EXTENSION
diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h
index d241c5b873dd97dfc9bff141614e6405392a97b0..0bdcc74ace5878fda5b56e1b697dedbaca78ed05 100644
--- a/gcc/config/aarch64/aarch64.h
+++ b/gcc/config/aarch64/aarch64.h
@@ -224,6 +224,9 @@ extern unsigned aarch64_architecture_version;
 /* 64-bit Floating-point Matrix Multiply (F64MM) extensions.  */
 #define AARCH64_FL_F64MM      (1ULL << 38)
 
+/* Flag Manipulation Instructions (FLAGM) extension.  */
+#define AARCH64_FL_FLAGM      (1ULL << 39)
+
 /* Has FP and SIMD.  */
 #define AARCH64_FL_FPSIMD     (AARCH64_FL_FP | AARCH64_FL_SIMD)
 
@@ -241,7 +244,7 @@ extern unsigned aarch64_architecture_version;
   (AARCH64_FL_FOR_ARCH8_2 | AARCH64_FL_V8_3)
 #define AARCH64_FL_FOR_ARCH8_4			\
   (AARCH64_FL_FOR_ARCH8_3 | AARCH64_FL_V8_4 | AARCH64_FL_F16FML \
-   | AARCH64_FL_DOTPROD | AARCH64_FL_RCPC8_4)
+   | AARCH64_FL_DOTPROD | AARCH64_FL_RCPC8_4 | AARCH64_FL_FLAGM)
 #define AARCH64_FL_FOR_ARCH8_5			\
   (AARCH64_FL_FOR_ARCH8_4 | AARCH64_FL_V8_5	\
    | AARCH64_FL_SB | AARCH64_FL_SSBS | AARCH64_FL_PREDRES)