diff --git a/arch/arm64/src/Toolchain.defs b/arch/arm64/src/Toolchain.defs
index a62d87c14e..c8d6052ca2 100644
--- a/arch/arm64/src/Toolchain.defs
+++ b/arch/arm64/src/Toolchain.defs
@@ -80,6 +80,11 @@ ifeq ($(CONFIG_MM_UBSAN_TRAP_ON_ERROR),y)
   ARCHOPTIMIZATION += -fsanitize-undefined-trap-on-error
 endif
 
+ifeq ($(CONFIG_ARCH_FPU),y)
+  ARCHCXXFLAGS += -D_LDBL_EQ_DBL
+  ARCHCFLAGS   += -D_LDBL_EQ_DBL
+endif
+
 ARCHCFLAGS += -fno-common
 ARCHCXXFLAGS += -fno-common -nostdinc++