https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106981
Tobias Burnus <burnus at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords|ice-on-valid-code |ice-on-invalid-code
--- Comment #2 from Tobias Burnus <burnus at gcc dot gnu.org> ---
Fails in
c_parser_binary_expression's POP for the second c_type_equal, which is
probably:
stack[sp].expr \
= convert_lvalue_to_rvalue (stack[sp].loc, \
stack[sp].expr, true, true); \
there:
c_tree_equal (t1=0x7ffff710dce0, t2=0x7ffff710dba0) at
../../repos/gcc-trunk-commit/gcc/c/c-typeck.cc:16039
(gdb) p debug((tree)0x7ffff710dce0)
*(totals + (sizetype) ((long unsigned int) (x % ((int) n / 10 + 1)) * 8))
(gdb) p debug((tree)0x7ffff710dba0)
*(totals + (sizetype) ((long unsigned int) (x % (int) ((unsigned int) (n / 10)
+ 1)) * 8))
where 'n' is 'long long' and 'x' and the digits are 'int' - the expr right of
'%' differs in terms of casts.
The ICE can be prevented with:
------------------------
--- a/gcc/c/c-typeck.cc
+++ b/gcc/c/c-typeck.cc
@@ -16216,6 +16216,9 @@ c_tree_equal (tree t1, tree t2)
&& n != TREE_OPERAND_LENGTH (t2))
return false;
+ if (n >= TREE_OPERAND_LENGTH (t2))
+ return false;
+
for (i = 0; i < n; ++i)
if (!c_tree_equal (TREE_OPERAND (t1, i), TREE_OPERAND (t2, i)))
return false;
------------------------
With this patch, the code fails – but C++ and C have different messages.
* gcc – points to tailing ';':
input5.i:7:86: error: invalid form of ‘#pragma omp atomic’ before ‘;’ token
7 | c[x] = totals[x%((int)(n/10 + 1))] = (a[x] + b[x]) +
totals[x%((int) n/10 + 1)];
|
^
* g++ - points to '(' in '... = (a[x ...':
input5.i:7:44: error: invalid form of ‘#pragma omp atomic’ before ‘(’ token
7 | c[x] = totals[x%((int)(n/10 + 1))] = (a[x] + b[x]) +
totals[x%((int) n/10 + 1)];
| ^
**************
Open... specification view. The expression is in the source code:
__v_ = __x________________________ = ____expr_____ +
________x'________________
c[x] = totals[x%((int)(n/10 + 1))] = (a[x] + b[x]) + totals[x%((int) n/10 +
1)];
and, obviously, x != x' due to the cast differences.
Looking at the OpenACC 3.2 spec, he last expr fits, except that x != x':
---------
If the atomic-clause is capture:
v = x++;
v = x--;
v = ++x;
v = --x;
v = x binop= expr;
v = x = x binop expr;
v = x = expr binop x;
---------
Likewise in OpenMP 5.2:
---------
An update-atomic structured block is update-expr-stmt, an update expression
statement that has one of the following forms:
...
x = x binop expr;
x = expr binop x;
...
A capture-atomic structured block is capture-stmt, a capture statement that
has one of the following forms:
v = expr-stmt
...
---------
