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re PR c/59871 (No unused value warning for comma expression)

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PR c/59871
c/
	* c-typeck.c (build_compound_expr): Warn even for right-hand operand
	of a comma expression.
	(emit_side_effect_warnings): Likewise.
libdecnumber/
	* decNumberLocal.h (UBFROMUS, UBFROMUI): Remove last argument.
testsuite/
	* gcc.dg/20020220-2.c: Adjust dg-warning message.
	* gcc.dg/pr59871.c: New test.

From-SVN: r207002
This commit is contained in:
Marek Polacek 2014-01-23 19:04:29 +00:00 • committed by Marek Polacek
parent 20f18c3ce1
commit 789eadcd54
7 changed files with 79 additions and 6 deletions
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7
gcc/c/ChangeLog
View file

@ -1,3 +1,10 @@
2014-01-23 Marek Polacek <polacek@redhat.com>
PR c/59871
* c-typeck.c (build_compound_expr): Warn even for right-hand operand
of a comma expression.
(emit_side_effect_warnings): Likewise.
2014-01-23 Balaji V. Iyer <balaji.v.iyer@intel.com>
PR c/59825

34
gcc/c/c-typeck.c
View file

@ -4778,6 +4778,23 @@ build_compound_expr (location_t loc, tree expr1, tree expr2)
"left-hand operand of comma expression has no effect");
}
}
else if (TREE_CODE (expr1) == COMPOUND_EXPR
&& warn_unused_value)
{
tree r = expr1;
location_t cloc = loc;
while (TREE_CODE (r) == COMPOUND_EXPR)
{
if (EXPR_HAS_LOCATION (r))
cloc = EXPR_LOCATION (r);
r = TREE_OPERAND (r, 1);
}
if (!TREE_SIDE_EFFECTS (r)
&& !VOID_TYPE_P (TREE_TYPE (r))
&& !CONVERT_EXPR_P (r))
warning_at (cloc, OPT_Wunused_value,
"right-hand operand of comma expression has no effect");
}
/* With -Wunused, we should also warn if the left-hand operand does have
side-effects, but computes a value which is not used. For example, in
@ -9643,6 +9660,23 @@ emit_side_effect_warnings (location_t loc, tree expr)
if (!VOID_TYPE_P (TREE_TYPE (expr)) && !TREE_NO_WARNING (expr))
warning_at (loc, OPT_Wunused_value, "statement with no effect");
}
else if (TREE_CODE (expr) == COMPOUND_EXPR)
{
tree r = expr;
location_t cloc = loc;
while (TREE_CODE (r) == COMPOUND_EXPR)
{
if (EXPR_HAS_LOCATION (r))
cloc = EXPR_LOCATION (r);
r = TREE_OPERAND (r, 1);
}
if (!TREE_SIDE_EFFECTS (r)
&& !VOID_TYPE_P (TREE_TYPE (r))
&& !CONVERT_EXPR_P (r)
&& !TREE_NO_WARNING (expr))
warning_at (cloc, OPT_Wunused_value,
"right-hand operand of comma expression has no effect");
}
else
warn_if_unused_value (expr, loc);
}

6
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,9 @@
2014-01-23 Marek Polacek <polacek@redhat.com>
PR c/59871
* gcc.dg/20020220-2.c: Adjust dg-warning message.
* gcc.dg/pr59871.c: New test.
2014-01-23 Paolo Carlini <paolo.carlini@oracle.com>
PR c++/58980

4
gcc/testsuite/gcc.dg/20020220-2.c
View file

@ -1,5 +1,5 @@
/* PR c/4697
Test whether value computed not used warning is given for compound
Test whether operand has no effect warning is given for compound
expression. */
/* { dg-do compile } */
/* { dg-options "-O2 -Wunused" } */
@ -7,6 +7,6 @@
int b;
int foo (int a)
{
a = a + 1, 5 * b; /* { dg-warning "value computed is not used" } */
a = a + 1, 5 * b; /* { dg-warning "right-hand operand of comma expression has no effect" } */
return a;
}

22
gcc/testsuite/gcc.dg/pr59871.c Normal file
View file

@ -0,0 +1,22 @@
/* PR c/59871 */
/* { dg-do compile } */
/* { dg-options "-Wunused" } */
extern int bar ();
void
foo (int *p, int i)
{
p[0] = (bar (), 1, bar ()); /* { dg-warning "right-hand operand of comma expression has no effect" } */
p[1] = (1, bar ()); /* { dg-warning "left-hand operand of comma expression has no effect" } */
bar (), 1, bar (); /* { dg-warning "right-hand operand of comma expression has no effect" } */
bar (), 1; /* { dg-warning "right-hand operand of comma expression has no effect" } */
1, bar (); /* { dg-warning "left-hand operand of comma expression has no effect" } */
(bar (), 1); /* { dg-warning "right-hand operand of comma expression has no effect" } */
bar (), 5 * i; /* { dg-warning "right-hand operand of comma expression has no effect" } */
(bar (), 5 * i); /* { dg-warning "right-hand operand of comma expression has no effect" } */
(bar (), (bar (), (bar (), (bar (), (bar (), (bar (), (bar (), 7))))))); /* { dg-warning "right-hand operand of comma expression has no effect" } */
bar (), (bar (), (bar (), (bar (), (bar (), (bar (), (bar (), 7)))))); /* { dg-warning "right-hand operand of comma expression has no effect" } */
bar (), (bar (), (bar (), (bar (), (bar (), (bar (), (7, bar ())))))); /* { dg-warning "left-hand operand of comma expression has no effect" } */
(bar (), (bar (), (bar (), (bar (), (bar (), (bar (), (7, bar ()))))))); /* { dg-warning "left-hand operand of comma expression has no effect" } */
}

5
libdecnumber/ChangeLog
View file

@ -1,3 +1,8 @@
2014-01-23 Marek Polacek <polacek@redhat.com>
PR c/59871
* decNumberLocal.h (UBFROMUS, UBFROMUI): Remove last argument.
2014-01-02 Richard Sandiford <rdsandiford@googlemail.com>
Update copyright years

7
libdecnumber/decNumberLocal.h
View file

@ -153,10 +153,9 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
#define UBTOUI(b) (memcpy((void *)&uiwork, b, 4), uiwork)
/* Store a uInt, etc., into bytes starting at a char* or uByte*. */
/* Returns i, evaluated, for convenience; has to use uiwork because */
/* i may be an expression. */
#define UBFROMUS(b, i) (uswork=(i), memcpy(b, (void *)&uswork, 2), uswork)
#define UBFROMUI(b, i) (uiwork=(i), memcpy(b, (void *)&uiwork, 4), uiwork)
/* Has to use uiwork because i may be an expression. */
#define UBFROMUS(b, i) (uswork=(i), memcpy(b, (void *)&uswork, 2))
#define UBFROMUI(b, i) (uiwork=(i), memcpy(b, (void *)&uiwork, 4))
/* X10 and X100 -- multiply integer i by 10 or 100 */
/* [shifts are usually faster than multiply; could be conditional] */