On 8/22/20 3:30 AM, Bruno Haible wrote:
-#if _GL_HAS_BUILTIN_UNREACHABLE
+ features such as function calls not inlined by the compiler. */
+
+#if _GL_HAS_BUILTIN_ASSUME
+/* Use a temporary variable, to avoid a clang warning
+ "the argument to '__builtin_assume' has side effects that will be discarded"
+ if R contains invocations of functions not marked as 'const'. */
+# define assume(R) \
+ ((void) ({ __typeof__ (R) _gl_verify_temp = (R); \
+ __builtin_assume (_gl_verify_temp); }))
+#elif _GL_HAS_BUILTIN_UNREACHABLE
# define assume(R) ((R) ? (void) 0 : __builtin_unreachable ())
This is OK, but please also mention in the comment that __builtin_assume
generates better code for Clang 8 than __builtin_unreachable does, as that's the
only reason to put up with all this mess.
