Fix some code suppression fallout

Some more subtle issues with code suppression:
- outputting asms but not their operand setup is broken
- but global asms must always be output
- statement expressions are transparent to code suppression
- vtop can't be transformed from VT_CMP/VT_JMP when nocode_wanted

Also remove .exe files from tests2 if they don't fail.

tests/tcctest.c

@@ -1404,6 +1404,15 @@ void optimize_out(void)
   if (defined_function() && 0)
     refer_to_undefined();
 
+  if (0) {
+      (void)sizeof( ({
+		     do { } while (0);
+		     0;
+		     }) );
+      undefined_function();
+  }
+
+  /* Leave the "if(1)return; printf()" in this order and last in the function */
   if (1)
     return;
   printf ("oor:%d\n", undefined_function());
@@ -3251,6 +3260,28 @@ void trace_console(long len, long len2)
       {
         printf("huh?\n");
       }
+#endif
+}
+
+void test_asm_dead_code(void)
+{
+  long rdi;
+  /* Try to make sure that xdi contains a zero, and hence will
+     lead to a segfault if the next asm is evaluated without
+     arguments being set up.  */
+  asm volatile ("" : "=D" (rdi) : "0" (0));
+  (void)sizeof (({
+      int var;
+      /* This shouldn't trigger a segfault, either the argument
+         registers need to be set up and the asm emitted despite
+	 this being in an unevaluated context, or both the argument
+	 setup _and_ the asm emission need to be suppressed.  The latter
+	 is better.  Disabling asm code gen when suppression is on
+	 also fixes the above trace_console bug, but that came earlier
+	 than asm suppression.  */
+      asm volatile ("movl $0,(%0)" : : "D" (&var) : "memory");
+      var;
+  }));
 }
 
 void asm_test(void)
@@ -3334,6 +3365,7 @@ void asm_test(void)
     printf ("fancycpy2(%d)=%d\n", val, val2);
     asm volatile ("mov $0x4243, %%esi" : "=r" (regvar));
     printf ("regvar=%x\n", regvar);
+    test_high_clobbers();
     trace_console(8, 8);
     test_asm_dead_code();
     return;

tests/tests2/85-asm-outside-function.c

@@ -1,7 +1,9 @@
+extern int printf (const char *, ...);
 extern void vide(void);
 __asm__("vide: ret");
 
 int main() {
     vide();
+    printf ("okay\n");
     return 0;
 }

tests/tests2/85-asm-outside-function.expect

@@ -0,0 +1 @@
+okay

tests/tests2/88_codeopt.c

@@ -0,0 +1,68 @@
+/* Check some way in where code suppression caused various
+   miscompilations.  */
+extern int printf (const char *, ...);
+typedef unsigned long size_t;
+
+size_t _brk_start, _brk_end;
+void * extend_brk(size_t size, size_t align)
+{
+    size_t mask = align - 1;
+    void *ret = 0;
+
+     do {
+	 if (__builtin_expect(!!(_brk_start == 0), 0))
+	   do {
+	       printf("wrong1\n");
+	   } while (0);
+     } while (0);
+     _brk_end = (_brk_end + mask) & ~mask;
+     ret = (void *)_brk_end;
+     _brk_end += size;
+
+     return ret;
+}
+
+static void get_args (int a, int b)
+{
+  if (a != 1)
+    printf("wrong2\n");
+  else
+    printf("okay\n");
+}
+
+void bla(void)
+{
+  int __ret = 42;
+  ({
+    if (__builtin_expect(!!(0), 0)) {
+      if (__builtin_expect(!!__ret, 0))
+        printf("wrong3\n");
+      int x = !!(__ret);
+    }
+    __ret;
+  });
+  get_args(!!__ret, sizeof(__ret));
+}
+
+_Bool chk(unsigned long addr, unsigned long limit, unsigned long size)
+{
+  _Bool ret;
+  /* This just needs to compile, no runtime test.  (And it doesn't compile
+     only with certain internal checking added that's not committed).  */
+  if (0)
+    ret = 0 != (!!(addr > limit - size));
+}
+
+int main()
+{
+  void *r;
+  _brk_start = 1024;
+  _brk_end = 1024;
+  r = extend_brk (4096, 16);
+  if (!r)
+    printf("wrong4\n");
+  else
+    printf("okay\n");
+  bla();
+  return 0;
+}

tests/tests2/88_codeopt.expect

@@ -0,0 +1,2 @@
+okay
+okay

tests/tests2/Makefile

@@ -59,7 +59,7 @@ all test: $(filter-out $(SKIP),$(TESTS))
 	    $(TCC) $< -o ./$*.exe $(FILTER) 2>&1 && \
 	    ./$*.exe $(ARGS) >$*.output 2>&1 || true; \
 	  fi
-	@diff -Nbu $(SRC)/$*.expect $*.output && rm -f $*.output
+	@diff -Nbu $(SRC)/$*.expect $*.output && rm -f $*.output $*.exe
 
 # automatically generate .expect files with gcc:
 %.expect : %.c