x86_64-asm: =m operand fixes

The problem was with tcctest.c:

    unsigned set;
    __asm__("btsl %1,%0" : "=m"(set) : "Ir"(20) : "cc");

when with tcc compiled with the HAVE_SELINUX option, run with
tcc -run, it would use large addresses far beyond the 32bits
range when tcc did not use the pc-relative mode for accessing
'set' in global data memory.  In fact the assembler did not
know about %rip at all.

Changes:
- memory operands use (%rax) not (%eax)
- conversion from VT_LLOCAL: use type VT_PTR
- support 'k' modifier
- support %rip register
- support X(%rip) pc-relative addresses

The test in tcctest.c is from Michael Matz.

tests/tcctest.c

@@ -2565,12 +2565,33 @@ static __inline__ unsigned long long inc64(unsigned long long a)
     __asm__("addl $1, %%eax ; adcl $0, %%edx" : "=A" (res) : "A" (a));
 #endif
     return res;
+}
+
+struct struct123 {
+    int a;
+    int b;
+};
+struct struct1231 {
+    unsigned long addr;
+};
+
+unsigned long mconstraint_test(struct struct1231 *r)
+{
+    unsigned long ret;
+    unsigned int a[2];
+    a[0] = 0;
+    __asm__ volatile ("lea %2,%0; movl 4(%0),%k0; addl %2,%k0; movl $51,%2; movl $52,4%2; movl $63,%1"
+	             : "=&r" (ret), "=m" (a)
+	             : "m" (*(struct struct123 *)r->addr));
+    return ret + a[0];
 }
 
 unsigned int set;
 
 void asm_test(void)
 {
+    char buf[128];
+    unsigned int val;
     struct struct123 s1;
     struct struct1231 s2 = { (unsigned long)&s1 };
 
@@ -2592,6 +2613,10 @@ void asm_test(void)
 
     /* 'A' constraint test */
     printf("mul64=0x%Lx\n", mul64(0x12345678, 0xabcd1234));
+    printf("inc64=0x%Lx\n", inc64(0x12345678ffffffff));
+
+    s1.a = 42;
+    s1.b = 43;
     printf("mconstraint: %d", mconstraint_test(&s2));
     printf(" %d %d\n", s1.a, s1.b);
     set = 0xff;
@@ -2600,9 +2625,6 @@ void asm_test(void)
     /* NOTE: we test here if C labels are correctly restored after the
        asm statement */
     goto label1;
- label2:
-    __asm__("btsl %1,%0" : "=m"(set) : "Ir"(20) : "cc");
-#ifdef __GNUC__ // works strange with GCC 4.3
  label2:
     __asm__("btsl %1,%0" : "=m"(set) : "Ir"(20) : "cc");
     printf("set=0x%x\n", set);