opt: constprop also 'cond && 0'

We didn't handle constants in logical expressions when they weren't
the first operand.  Some reordering in the loop structure is enough
to handle them.

tccgen.c

@@ -4909,31 +4909,38 @@ static void expr_land(void)
 {
     expr_or();
     if (tok == TOK_LAND) {
+	int t = 0;
+	for(;;) {
 	    if ((vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST) {
-            CType ctb, cti;
+		CType ctb;
 		ctb.t = VT_BOOL;
-            cti.t = VT_INT;
-            next();
 		gen_cast(&ctb);
 		if (vtop->c.i) {
 		    vpop();
-                expr_land();
-                gen_cast(&ctb);
 		} else {
 		    int saved_nocode_wanted = nocode_wanted;
 		    nocode_wanted = 1;
-                expr_land();
+		    while (tok == TOK_LAND) {
+			next();
+			expr_or();
 			vpop();
-                nocode_wanted = saved_nocode_wanted;
 		    }
-            gen_cast(&cti);
+		    if (t)
+		      gsym(t);
+		    nocode_wanted = saved_nocode_wanted;
+		    gen_cast(&int_type);
+		    break;
+		}
 	    } else {
-            int t = 0;
+		if (!t)
 		  save_regs(1);
-            for(;;) {
 		t = gvtst(1, t);
+	    }
 	    if (tok != TOK_LAND) {
+		if (t)
 		  vseti(VT_JMPI, t);
+		else
+		  vpushi(1);
 		break;
 	    }
 	    next();
@@ -4941,37 +4948,43 @@ static void expr_land(void)
 	}
     }
 }
-}
 
 static void expr_lor(void)
 {
     expr_land();
     if (tok == TOK_LOR) {
+	int t = 0;
+	for(;;) {
 	    if ((vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST) {
-            CType ctb, cti;
+		CType ctb;
 		ctb.t = VT_BOOL;
-            cti.t = VT_INT;
-            next();
 		gen_cast(&ctb);
-            if (vtop->c.i) {
+		if (!vtop->c.i) {
+		    vpop();
+		} else {
 		    int saved_nocode_wanted = nocode_wanted;
 		    nocode_wanted = 1;
-                expr_lor();
+		    while (tok == TOK_LOR) {
+			next();
+			expr_land();
 			vpop();
-                nocode_wanted = saved_nocode_wanted;
-            } else {
-                vpop();
-                expr_lor();
-                gen_cast(&ctb);
 		    }
-            gen_cast(&cti);
+		    if (t)
+		      gsym(t);
+		    nocode_wanted = saved_nocode_wanted;
+		    gen_cast(&int_type);
+		    break;
+		}
 	    } else {
-            int t = 0;
+		if (!t)
 		  save_regs(1);
-            for(;;) {
 		t = gvtst(0, t);
+	    }
 	    if (tok != TOK_LOR) {
+		if (t)
 		  vseti(VT_JMP, t);
+		else
+		  vpushi(0);
 		break;
 	    }
 	    next();
@@ -4979,7 +4992,6 @@ static void expr_lor(void)
 	}
     }
 }
-}
 
 /* Assuming vtop is a value used in a conditional context
    (i.e. compared with zero) return 0 if it's false, 1 if

tests/tcctest.c

@@ -1232,6 +1232,38 @@ void optimize_out(void)
       printf("ool6:%d\n", defined_function());
       goto breakhere;
   }
+
+  /* Test that constants in logical && are optimized: */
+  i = 0 && undefined_function();
+  i = defined_function() && 0 && undefined_function();
+  if (0 && undefined_function())
+    undefined_function();
+  if (defined_function() && 0)
+    undefined_function();
+  if (0 && 0)
+    undefined_function();
+  if (defined_function() && 0 && undefined_function())
+    undefined_function();
+  /* The same for || : */
+  i = 1 || undefined_function();
+  i = defined_function() || 1 || undefined_function();
+  if (1 || undefined_function())
+    ;
+  else
+    undefined_function();
+  if (defined_function() || 1)
+    ;
+  else
+    undefined_function();
+  if (1 || 1)
+    ;
+  else
+    undefined_function();
+  if (defined_function() || 1 || undefined_function())
+    ;
+  else
+    undefined_function();
+
   if (1)
     return;
   printf ("oor:%d\n", undefined_function());
@@ -2544,6 +2576,13 @@ void sizeof_test(void)
     printf("sizeof( (struct {int i; int j;}){4,5} ) = %d\n",
 	   sizeof( (struct {int i; int j;}){4,5} ));
     /* And as direct sizeof argument (as unary expression): */
+    printf("sizeof (struct {short i; short j;}){4,5} = %d\n",
+	   sizeof (struct {short i; short j;}){4,5} );
+
+    /* sizeof(x && y) should be sizeof(int), even if constant
+       evaluating is possible. */
+    printf("sizeof(t && 0) = %d\n", sizeof(t && 0));
+    printf("sizeof(1 && 1) = %d\n", sizeof(1 && 1));
     printf("sizeof(t || 1) = %d\n", sizeof(t || 1));
     printf("sizeof(0 || 0) = %d\n", sizeof(0 || 0));
 }