Add stub support for the asm constraint modifier '%'.

NEWS.md

@@ -5,6 +5,7 @@ libFirm 1.22.1 (2016-01-07)
 * Add `ia32-get_ip={pop,thunk}`
 * Generate 'mov $~1, %r; rol x, %r' for '~(1 << x)' (ia32)
 * Generate 'mov $~0x80000000, %r; ror x, %r' for '~(0x80000000 >> x)' (ia32)
+* Stub support for the asm constraint modifier '%'
 * Bugfixes
 
 libFirm 1.22.0 (2015-12-31)

ir/be/beasm.c

@@ -82,6 +82,7 @@ void be_parse_asm_constraints_internal(be_asm_constraint_t *const constraint, id
 		case ' ':
 		case '\t':
 		case '\n':
+		case '%':
 		case '=':
 		case '+':
 		case '&':

ir/be/bemain.c

@@ -137,7 +137,7 @@ static void be_init_default_asm_constraint_flags(void)
 	/* List of constraints supported by gcc for any machine (or at least
 	 * recognized). Mark them as NO_SUPPORT so we can differentiate them
 	 * from INVALID. Backends should change the flags they support. */
-	char const *const gcc_common_flags = "%,0123456789<>EFGHIJKLMNOPVXgimoprs";
+	char const *const gcc_common_flags = ",0123456789<>EFGHIJKLMNOPVXgimoprs";
 	be_set_constraint_support(ASM_CONSTRAINT_FLAG_NO_SUPPORT, gcc_common_flags);
 	/* Skip whitespace.
 	 * TODO '*' actually penalizes the selection of the next constraint letter.
@@ -173,6 +173,7 @@ asm_constraint_flags_t be_parse_asm_constraints(const char *constraint)
 	switch (*c) {
 	case '=': ++c; flags = ASM_CONSTRAINT_FLAG_MODIFIER_WRITE; break;
 	case '+': ++c; flags = ASM_CONSTRAINT_FLAG_MODIFIER_READ | ASM_CONSTRAINT_FLAG_MODIFIER_WRITE; break;
+	case '%': ++c; /* FALLTHROUGH */ /* TODO stub, should mark this operand as commutative with the next. */
 	default:       flags = ASM_CONSTRAINT_FLAG_MODIFIER_READ; break;
 	}