[PATCH] c++: non-dependent call to consteval operator [PR105912]

[PATCH] c++: non-dependent call to consteval operator [PR105912]

[Patrick Palka]

Here we were crashing when substituting a non-dependent call to a
consteval operator, whose CALL_EXPR_OPERATOR_SYNTAX flag we try to
propagate to the result, but the result isn't a CALL_EXPR since the
called function is consteval.  This patch fixes this by checking the
result of extract_call_expr accordingly.  (Note that we can't easily
check DECL_IMMEDIATE_FUNCTION_P here because we don't know which
function was selected by overload resolution from this call frame.)

Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK
for trunk/12?

	PR c++/105912

gcc/cp/ChangeLog:

	* pt.cc (tsubst_copy_and_build) <case CALL_EXPR>: Guard against
	NULL_TREE extract_call_expr result.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp2a/consteval31.C: New test.
---
 gcc/cp/pt.cc                             | 10 +++++----
 gcc/testsuite/g++.dg/cpp2a/consteval31.C | 26 ++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 4 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp2a/consteval31.C

diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 232964c2831..8a6ae5c42fe 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -21207,10 +21207,12 @@ tsubst_copy_and_build (tree t,
 	    bool rev = CALL_EXPR_REVERSE_ARGS (t);
 	    if (op || ord || rev)
 	      {
-		function = extract_call_expr (ret);
-		CALL_EXPR_OPERATOR_SYNTAX (function) = op;
-		CALL_EXPR_ORDERED_ARGS (function) = ord;
-		CALL_EXPR_REVERSE_ARGS (function) = rev;
+		if (tree call = extract_call_expr (ret))
+		  {
+		    CALL_EXPR_OPERATOR_SYNTAX (call) = op;
+		    CALL_EXPR_ORDERED_ARGS (call) = ord;
+		    CALL_EXPR_REVERSE_ARGS (call) = rev;
+		  }
 	      }
 	  }
 
diff --git a/gcc/testsuite/g++.dg/cpp2a/consteval31.C b/gcc/testsuite/g++.dg/cpp2a/consteval31.C
new file mode 100644
index 00000000000..85a4d1794e5
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/consteval31.C
@@ -0,0 +1,26 @@
+// PR c++/105912
+// { dg-do compile { target c++20 } }
+
+struct A {
+  consteval A operator+() {
+    return {};
+  }
+};
+
+consteval A operator~(A) {
+  return {};
+}
+
+consteval A operator+(A, A) {
+  return {};
+}
+
+template<class>
+void f() {
+  A a;
+  ~a;
+  a + a;
+  +a;
+}
+
+template void f<int>();
-- 
2.37.0.3.g30cc8d0f14

Re: [PATCH] c++: non-dependent call to consteval operator [PR105912]

[Jason Merrill]

On 7/11/22 21:27, Patrick Palka wrote:
> Here we were crashing when substituting a non-dependent call to a
> consteval operator, whose CALL_EXPR_OPERATOR_SYNTAX flag we try to
> propagate to the result, but the result isn't a CALL_EXPR since the
> called function is consteval.  This patch fixes this by checking the
> result of extract_call_expr accordingly.  (Note that we can't easily
> check DECL_IMMEDIATE_FUNCTION_P here because we don't know which
> function was selected by overload resolution from this call frame.)
> 
> Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK
> for trunk/12?
> 
> 	PR c++/105912
> 
> gcc/cp/ChangeLog:
> 
> 	* pt.cc (tsubst_copy_and_build) <case CALL_EXPR>: Guard against
> 	NULL_TREE extract_call_expr result.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* g++.dg/cpp2a/consteval31.C: New test.
> ---
>   gcc/cp/pt.cc                             | 10 +++++----
>   gcc/testsuite/g++.dg/cpp2a/consteval31.C | 26 ++++++++++++++++++++++++
>   2 files changed, 32 insertions(+), 4 deletions(-)
>   create mode 100644 gcc/testsuite/g++.dg/cpp2a/consteval31.C
> 
> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> index 232964c2831..8a6ae5c42fe 100644
> --- a/gcc/cp/pt.cc
> +++ b/gcc/cp/pt.cc
> @@ -21207,10 +21207,12 @@ tsubst_copy_and_build (tree t,
>   	    bool rev = CALL_EXPR_REVERSE_ARGS (t);
>   	    if (op || ord || rev)
>   	      {

I'd drop this pair of braces.  OK either way.

> -		function = extract_call_expr (ret);
> -		CALL_EXPR_OPERATOR_SYNTAX (function) = op;
> -		CALL_EXPR_ORDERED_ARGS (function) = ord;
> -		CALL_EXPR_REVERSE_ARGS (function) = rev;
> +		if (tree call = extract_call_expr (ret))
> +		  {
> +		    CALL_EXPR_OPERATOR_SYNTAX (call) = op;
> +		    CALL_EXPR_ORDERED_ARGS (call) = ord;
> +		    CALL_EXPR_REVERSE_ARGS (call) = rev;
> +		  }
>   	      }
>   	  }
>   
> diff --git a/gcc/testsuite/g++.dg/cpp2a/consteval31.C b/gcc/testsuite/g++.dg/cpp2a/consteval31.C
> new file mode 100644
> index 00000000000..85a4d1794e5
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp2a/consteval31.C
> @@ -0,0 +1,26 @@
> +// PR c++/105912
> +// { dg-do compile { target c++20 } }
> +
> +struct A {
> +  consteval A operator+() {
> +    return {};
> +  }
> +};
> +
> +consteval A operator~(A) {
> +  return {};
> +}
> +
> +consteval A operator+(A, A) {
> +  return {};
> +}
> +
> +template<class>
> +void f() {
> +  A a;
> +  ~a;
> +  a + a;
> +  +a;
> +}
> +
> +template void f<int>();