Hi,
I've noticed that there is already a -Wparentheses warning for code like
int y = x == 2 ?: 1
=> warning: the omitted middle operand in ?: will always be 'true',
suggest explicit middle operand [-Wparentheses]
But it is not emitted for code that uses bool, like:
void foo(bool x)
{
int y = x ?: 1;
and under C it is not emitted for compound expressions
that end with a comparison, like:
int y = (i++,i==1) ?: 1;
C++ is OK, but does only miss to warn on the bool data type.
The attached patch should fix these warnings.
Bootstrap and reg-testing is still running,
Is it OK for trunk after reg-testing?
Thanks
Bernd.
gcc/c-family:
2016-09-05 Bernd Edlinger <bernd.edlin...@hotmail.de>
* c-common.c (warn_for_omitted_condop): Also warn for boolean data.
gcc/c:
2016-09-05 Bernd Edlinger <bernd.edlin...@hotmail.de>
* c-parser.c (c_parser_conditional_expression): Pass the rightmost
COMPOUND_EXPR to warn_for_omitted_condop.
testsuite:
2016-09-05 Bernd Edlinger <bernd.edlin...@hotmail.de>
* c-c++-common/warn-ommitted-condop.c: Add more test cases.
Index: gcc/c/c-parser.c
===================================================================
--- gcc/c/c-parser.c (revision 240001)
+++ gcc/c/c-parser.c (working copy)
@@ -6423,16 +6423,20 @@ c_parser_conditional_expression (c_parser *parser,
if (c_parser_next_token_is (parser, CPP_COLON))
{
tree eptype = NULL_TREE;
+ tree e;
middle_loc = c_parser_peek_token (parser)->location;
pedwarn (middle_loc, OPT_Wpedantic,
"ISO C forbids omitting the middle term of a ?: expression");
- warn_for_omitted_condop (middle_loc, cond.value);
if (TREE_CODE (cond.value) == EXCESS_PRECISION_EXPR)
{
eptype = TREE_TYPE (cond.value);
cond.value = TREE_OPERAND (cond.value, 0);
}
+ e = cond.value;
+ while (TREE_CODE (e) == COMPOUND_EXPR)
+ e = TREE_OPERAND (e, 1);
+ warn_for_omitted_condop (middle_loc, e);
/* Make sure first operand is calculated only once. */
exp1.value = c_save_expr (default_conversion (cond.value));
if (eptype)
Index: gcc/c-family/c-common.c
===================================================================
--- gcc/c-family/c-common.c (revision 240001)
+++ gcc/c-family/c-common.c (working copy)
@@ -10619,7 +10619,8 @@ fold_offsetof (tree expr)
void
warn_for_omitted_condop (location_t location, tree cond)
{
- if (truth_value_p (TREE_CODE (cond)))
+ if (TREE_CODE (TREE_TYPE (cond)) == BOOLEAN_TYPE
+ || truth_value_p (TREE_CODE (cond)))
warning_at (location, OPT_Wparentheses,
"the omitted middle operand in ?: will always be %<true%>, "
"suggest explicit middle operand");
Index: gcc/testsuite/c-c++-common/warn-ommitted-condop.c
===================================================================
--- gcc/testsuite/c-c++-common/warn-ommitted-condop.c (revision 240001)
+++ gcc/testsuite/c-c++-common/warn-ommitted-condop.c (working copy)
@@ -1,8 +1,12 @@
/* { dg-options "-Wparentheses -ftrack-macro-expansion=0" } */
+#ifndef __cplusplus
+#define bool _Bool
+#endif
+
extern void f2 (int);
-void bar (int x, int y, int z)
+void bar (int x, int y, int z, bool b)
{
#define T(op) f2 (x op y ? : 1)
#define T2(op) f2 (x op y ? 2 : 1)
@@ -16,6 +20,8 @@ extern void f2 (int);
T(||); /* { dg-warning "omitted middle operand" } */
T(&&); /* { dg-warning "omitted middle operand" } */
f2 (!x ? : 1); /* { dg-warning "omitted middle operand" } */
+ f2 ((x,!x) ? : 1); /* { dg-warning "omitted middle operand" } */
+ f2 ((x,y,!x) ? : 1); /* { dg-warning "omitted middle operand" } */
T2(<); /* { dg-bogus "omitted middle operand" } */
T2(>); /* { dg-bogus "omitted middle operand" } */
T2(==); /* { dg-bogus "omitted middle operand" } */
@@ -26,4 +32,5 @@ extern void f2 (int);
T(*); /* { dg-bogus "omitted middle operand" } */
T(/); /* { dg-bogus "omitted middle operand" } */
T(^); /* { dg-bogus "omitted middle operand" } */
+ f2 (b ? : 1); /* { dg-warning "omitted middle operand" } */
}
