OpenE2K
/
gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

c++: Fix pretty-print of pointer minus integer. 

For whatever reason, GCC internally represents a pointer minus an integer as
a pointer plus a very large unsigned integer.  But exposing that to users is
unsightly, and it's easy enough to show the real value.

gcc/cp/ChangeLog:

	* error.c (dump_binary_op): Handle negative operand to
	POINTER_PLUS_EXPR.

gcc/c-family/ChangeLog:

	* c-pretty-print.c (pp_c_additive_expression): Handle negative
	operand to POINTER_PLUS_EXPR.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/constexpr-ptrsub2.C: New test.
This commit is contained in:
Jason Merrill 2020-06-04 15:56:57 -04:00
parent 640e05e02b
commit 5094c4400a
3 changed files with 22 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
gcc/c-family/c-pretty-print.c
View File

@ -1898,7 +1898,16 @@ pp_c_additive_expression (c_pretty_printer *pp, tree e)
else
pp_minus (pp);
pp_c_whitespace (pp);
pp->multiplicative_expression (TREE_OPERAND (e, 1));
{
tree op1 = TREE_OPERAND (e, 1);
if (code == POINTER_PLUS_EXPR
&& TREE_CODE (op1) == INTEGER_CST
&& tree_int_cst_sign_bit (op1))
/* A pointer minus an integer is represented internally as plus a very
large number, don't expose that to users. */
op1 = convert (ssizetype, op1);
pp->multiplicative_expression (op1);
}
break;
default:

9
gcc/cp/error.c
View File

@ -2909,7 +2909,14 @@ dump_binary_op (cxx_pretty_printer *pp, const char *opstring, tree t,
else
pp_string (pp, M_("<unknown operator>"));
pp_cxx_whitespace (pp);
dump_expr (pp, TREE_OPERAND (t, 1), flags | TFF_EXPR_IN_PARENS);
tree op1 = TREE_OPERAND (t, 1);
if (TREE_CODE (t) == POINTER_PLUS_EXPR
&& TREE_CODE (op1) == INTEGER_CST
&& tree_int_cst_sign_bit (op1))
/* A pointer minus an integer is represented internally as plus a very
large number, don't expose that to users. */
op1 = convert (ssizetype, op1);
dump_expr (pp, op1, flags | TFF_EXPR_IN_PARENS);
pp_cxx_right_paren (pp);
}

4
gcc/testsuite/g++.dg/cpp0x/constexpr-ptrsub2.C Normal file
View File

@ -0,0 +1,4 @@
// { dg-do compile { target c++11 } }
char c;
constexpr char p2 = *(&c - 1); // { dg-error "-1" }