On 6/23/21 7:37 PM, Patrick Palka wrote:
Here we're crashing because cp_fold_function walks into the (templated)
requirements of a requires-expression outside a template, but the
folding routines aren't prepared to handle templated trees. This patch
fixes this by making cp_fold use evaluate_requires_expr to fold a
requires-expression as a whole, which also means we no longer need to
explicitly do so during gimplification. (We don't immediately fold
non-dependent requires-expressions at parse time for sake of better
diagnostics in case one appears as the condition of a failed
static_assert.)
Bootstrapped and regtested on x86_64-pc-linux-gnu, also tested on
cmcstl2 and range-v3, does this look OK for trunk/11?
OK.
PR c++/101182
gcc/cp/ChangeLog:
* constraint.cc (evaluate_requires_expr): Adjust function comment.
* cp-gimplify.c (cp_genericize_r) <case REQUIRES_EXPR>: Move to ...
(cp_fold) <case REQUIRES_EXPR>: ... here.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/concepts-requires27.C: New test.
---
gcc/cp/constraint.cc | 2 +-
gcc/cp/cp-gimplify.c | 10 ++++------
gcc/testsuite/g++.dg/cpp2a/concepts-requires27.C | 10 ++++++++++
3 files changed, 15 insertions(+), 7 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-requires27.C
diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
index 74b16d27101..286332ba2a7 100644
--- a/gcc/cp/constraint.cc
+++ b/gcc/cp/constraint.cc
@@ -3340,7 +3340,7 @@ evaluate_concept_check (tree check)
}
/* Evaluate the requires-expression T, returning either boolean_true_node
- or boolean_false_node. This is used during gimplification and constexpr
+ or boolean_false_node. This is used during folding and constexpr
evaluation. */
tree
diff --git a/gcc/cp/cp-gimplify.c b/gcc/cp/cp-gimplify.c
index 96d91b6ef2f..33e10556e32 100644
--- a/gcc/cp/cp-gimplify.c
+++ b/gcc/cp/cp-gimplify.c
@@ -1465,12 +1465,6 @@ cp_genericize_r (tree *stmt_p, int *walk_subtrees, void
*data)
TARGET_EXPR_NO_ELIDE (stmt) = 1;
break;
- case REQUIRES_EXPR:
- /* Emit the value of the requires-expression. */
- *stmt_p = evaluate_requires_expr (stmt);
- *walk_subtrees = 0;
- break;
-
case TEMPLATE_ID_EXPR:
gcc_assert (concept_check_p (stmt));
/* Emit the value of the concept check. */
@@ -2708,6 +2702,10 @@ cp_fold (tree x)
x = r;
break;
+ case REQUIRES_EXPR:
+ x = evaluate_requires_expr (x);
+ break;
+
default:
return org_x;
}
diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-requires27.C
b/gcc/testsuite/g++.dg/cpp2a/concepts-requires27.C
new file mode 100644
index 00000000000..87a759a689a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/concepts-requires27.C
@@ -0,0 +1,10 @@
+// PR c++/101182
+// { dg-do compile { target concepts } }
+
+int a;
+int g(bool);
+
+int f() {
+ g(requires { a++; });
+ return requires { a++; };
+}
