On 12/12/23 17:48, Marek Polacek wrote:
On Fri, Dec 08, 2023 at 11:09:15PM -0500, Jason Merrill wrote:
On 12/8/23 16:15, Marek Polacek wrote:
On Fri, Dec 08, 2023 at 12:09:18PM -0500, Jason Merrill wrote:
On 12/5/23 15:31, Marek Polacek wrote:
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
-- >8 --
This test shows that we cannot clear *walk_subtrees in
cp_fold_immediate_r when we're in_immediate_context, because that,
as the comment says, affects cp_fold_r as well. Here we had an
expression with
min ((long int) VIEW_CONVERT_EXPR<long unsigned int>(bytecount), (long int)
<<< Unknown tree: sizeof_expr
(int) <<< error >>> >>>)
as its sub-expression, and we never evaluated that into
min ((long int) bytecount, 4)
so the SIZEOF_EXPR leaked into the middle end.
(There's still one *walk_subtrees = 0; in cp_fold_immediate_r, but that
one should be OK.)
PR c++/112869
gcc/cp/ChangeLog:
* cp-gimplify.cc (cp_fold_immediate_r): Don't clear *walk_subtrees
for unevaluated operands.
I agree that we want this change for in_immediate_context (), but I don't
see why we want it for TYPE_P or unevaluated_p (code) or
cp_unevaluated_operand?
No particular reason, just paranoia. How's this?
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
-- >8 --
This test shows that we cannot clear *walk_subtrees in
cp_fold_immediate_r when we're in_immediate_context, because that,
as the comment says, affects cp_fold_r as well. Here we had an
expression with
min ((long int) VIEW_CONVERT_EXPR<long unsigned int>(bytecount), (long int)
<<< Unknown tree: sizeof_expr
(int) <<< error >>> >>>)
as its sub-expression, and we never evaluated that into
min ((long int) bytecount, 4)
so the SIZEOF_EXPR leaked into the middle end.
(There's still one *walk_subtrees = 0; in cp_fold_immediate_r, but that
one should be OK.)
PR c++/112869
gcc/cp/ChangeLog:
* cp-gimplify.cc (cp_fold_immediate_r): Don't clear *walk_subtrees
for in_immediate_context.
gcc/testsuite/ChangeLog:
* g++.dg/template/sizeof18.C: New test.
---
gcc/cp/cp-gimplify.cc | 6 +++++-
gcc/testsuite/g++.dg/template/sizeof18.C | 8 ++++++++
2 files changed, 13 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/template/sizeof18.C
diff --git a/gcc/cp/cp-gimplify.cc b/gcc/cp/cp-gimplify.cc
index 5abb91bbdd3..6af7c787372 100644
--- a/gcc/cp/cp-gimplify.cc
+++ b/gcc/cp/cp-gimplify.cc
@@ -1179,11 +1179,15 @@ cp_fold_immediate_r (tree *stmt_p, int *walk_subtrees,
void *data_)
/* No need to look into types or unevaluated operands.
NB: This affects cp_fold_r as well. */
- if (TYPE_P (stmt) || unevaluated_p (code) || in_immediate_context ())
+ if (TYPE_P (stmt) || unevaluated_p (code))
{
*walk_subtrees = 0;
return NULL_TREE;
}
+ else if (in_immediate_context ())
+ /* Don't clear *walk_subtrees here: we still need to walk the subtrees
+ of SIZEOF_EXPR and similar. */
+ return NULL_TREE;
tree decl = NULL_TREE;
bool call_p = false;
diff --git a/gcc/testsuite/g++.dg/template/sizeof18.C
b/gcc/testsuite/g++.dg/template/sizeof18.C
new file mode 100644
index 00000000000..afba9946258
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/sizeof18.C
@@ -0,0 +1,8 @@
+// PR c++/112869
+// { dg-do compile }
+
+void min(long, long);
+template <class T> void Binaryread(int &, T, unsigned long);
+template <> void Binaryread(int &, float, unsigned long bytecount) {
+ min(bytecount, sizeof(int));
+}
Hmm, actually, why does the above make a difference for this testcase?
...
It seems that in_immediate_context always returns true in cp_fold_function
because current_binding_level->kind == sk_template_parms. That seems like a
problem. Maybe for cp_fold_immediate_r we only want to check
cp_unevaluated_operand or DECL_IMMEDIATE_CONTEXT (current_function_decl)?
Yeah, I suppose that could become an issue. How about this, then?
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
-- >8 --
This test shows that we cannot clear *walk_subtrees in
cp_fold_immediate_r when we're in_immediate_context, because that,
as the comment says, affects cp_fold_r as well. Here we had an
expression with
min ((long int) VIEW_CONVERT_EXPR<long unsigned int>(bytecount), (long int)
<<< Unknown tree: sizeof_expr
(int) <<< error >>> >>>)
as its sub-expression, and we never evaluated that into
min ((long int) bytecount, 4)
so the SIZEOF_EXPR leaked into the middle end.
(There's still one *walk_subtrees = 0; in cp_fold_immediate_r, but that
one should be OK.)
PR c++/112869
gcc/cp/ChangeLog:
* cp-gimplify.cc (cp_fold_immediate_r): Don't clear *walk_subtrees
in an unevaluated operand or immediate function.
gcc/testsuite/ChangeLog:
* g++.dg/template/sizeof18.C: New test.
---
gcc/cp/cp-gimplify.cc | 8 +++++++-
gcc/testsuite/g++.dg/template/sizeof18.C | 8 ++++++++
2 files changed, 15 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/template/sizeof18.C
diff --git a/gcc/cp/cp-gimplify.cc b/gcc/cp/cp-gimplify.cc
index c307e1b62db..413ebafbd1a 100644
--- a/gcc/cp/cp-gimplify.cc
+++ b/gcc/cp/cp-gimplify.cc
@@ -1179,11 +1179,17 @@ cp_fold_immediate_r (tree *stmt_p, int *walk_subtrees,
void *data_)
/* No need to look into types or unevaluated operands.
NB: This affects cp_fold_r as well. */
- if (TYPE_P (stmt) || unevaluated_p (code) || in_immediate_context ())
+ if (TYPE_P (stmt) || unevaluated_p (code))
{
*walk_subtrees = 0;
return NULL_TREE;
}
+ else if (cp_unevaluated_operand
+ || (current_function_decl
+ && DECL_IMMEDIATE_FUNCTION_P (current_function_decl)))
It should still be fine to clear *walk_subtrees in these cases; the
problem I was talking about above was that in_immediate_context was
returning true for all functions, not just consteval functions.
I think the fix is not adding an else, but rather replacing the
in_immediate_context call with "unevaluated or consteval cfun".
+ /* Don't clear *walk_subtrees here: we still need to walk the subtrees
+ of SIZEOF_EXPR and similar. */
We shouldn't need to walk subtrees of SIZEOF_EXPR or other unevaluated
operands, they'll all get cp_folded away. The bug was that we weren't
calling cp_fold on the SIZEOF_EXPR itself.
Jason
