Make asm without side-effects not optimisable-out
Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/library/sha256.c b/library/sha256.c
index e655cf8..18be8a4 100644
--- a/library/sha256.c
+++ b/library/sha256.c
@@ -202,9 +202,9 @@
if (setjmp(return_from_sigill) == 0) { /* First return only */
/* If this traps, we will return a second time from setjmp() with 1 */
#if defined(MBEDTLS_ARCH_IS_ARM64)
- asm ("sha256h q0, q0, v0.4s" : : : "v0");
+ asm volatile ("sha256h q0, q0, v0.4s" : : : "v0");
#else
- asm ("sha256h.32 q0, q0, q0" : : : "q0");
+ asm volatile ("sha256h.32 q0, q0, q0" : : : "q0");
#endif
ret = 1;
}