From: Jason Merrill <jason@redhat.com>
Date: Tue, 20 Sep 2022 21:12:29 +0000 (-0400)
Subject: c++: check DECL_INITIAL for constexpr
X-Git-Tag: basepoints/gcc-14~4242
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=73d9b0e5947e162386f7e25d3851097cee1bb366;p=thirdparty%2Fgcc.git

c++: check DECL_INITIAL for constexpr

We were overlooking non-potentially-constant bits in variable initializer
because we didn't walk into DECL_INITIAL.

gcc/cp/ChangeLog:

	* constexpr.cc (potential_constant_expression_1): Look into
	DECL_INITIAL.  Use location wrappers.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp1y/constexpr-local4.C: Expect error sooner.
	* g++.dg/cpp2a/consteval24.C: Likewise.
	* g++.dg/cpp2a/consteval7.C: Likewise.
	* g++.dg/cpp2a/inline-asm3.C: Likewise.
---

diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc
index 10639876d9cf..ed41d7552696 100644
--- a/gcc/cp/constexpr.cc
+++ b/gcc/cp/constexpr.cc
@@ -8892,7 +8892,10 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now,
       {
         tree from = TREE_OPERAND (t, 0);
 	if (location_wrapper_p (t))
-	  return (RECUR (from, want_rval));
+	  {
+	    iloc_sentinel ils = loc;
+	    return (RECUR (from, want_rval));
+	  }
 	if (INDIRECT_TYPE_P (TREE_TYPE (t)))
 	  {
 	    STRIP_ANY_LOCATION_WRAPPER (from);
@@ -9348,7 +9351,7 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now,
 		   (tmp, /*constexpr_context_p=*/true, flags))
 	    return false;
 	}
-      return RECUR (tmp, want_rval);
+      return RECUR (DECL_INITIAL (tmp), want_rval);
 
     case TRY_FINALLY_EXPR:
       return (RECUR (TREE_OPERAND (t, 0), want_rval)
diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-local4.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-local4.C
index bef624885792..647b5dcd7cd5 100644
--- a/gcc/testsuite/g++.dg/cpp1y/constexpr-local4.C
+++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-local4.C
@@ -10,8 +10,8 @@ const A a = 42;
 
 constexpr int f()
 {
-  const int j = a.i;		// { dg-message "'a'" }
+  const int j = a.i;		// { dg-error "'a'" }
   return j;
 }
 
-static_assert (f() == 42,"");	// { dg-error "non-constant" }
+static_assert (f() == 42,"");	// { dg-error "" }
diff --git a/gcc/testsuite/g++.dg/cpp2a/consteval24.C b/gcc/testsuite/g++.dg/cpp2a/consteval24.C
index 6d0c63c749be..6d7034c5515e 100644
--- a/gcc/testsuite/g++.dg/cpp2a/consteval24.C
+++ b/gcc/testsuite/g++.dg/cpp2a/consteval24.C
@@ -27,4 +27,4 @@ bar ()
   return fn1 () + fn2 () + (s.*fn3) () + (s.*fn4) () + fn5 () + (s.*fn6) () + (s.*fn7) ();
 }
 
-auto a = bar ();
+auto a = bar ();		// { dg-error "bar" }
diff --git a/gcc/testsuite/g++.dg/cpp2a/consteval7.C b/gcc/testsuite/g++.dg/cpp2a/consteval7.C
index 23f3d25a39e0..74996d31a82e 100644
--- a/gcc/testsuite/g++.dg/cpp2a/consteval7.C
+++ b/gcc/testsuite/g++.dg/cpp2a/consteval7.C
@@ -10,4 +10,4 @@ consteval int qux () { S s = baz (); return s.b + s.c (); }
 consteval int quux () { constexpr S s = baz (); return s.b + s.c (); }	// { dg-error "immediate evaluation returns address of immediate function 'consteval int foo\\(\\)'" }
 constexpr auto d = baz ();	// { dg-error "immediate evaluation returns address of immediate function 'consteval int foo\\(\\)'" }
 constexpr auto e = qux ();
-constexpr auto f = quux ();
+constexpr auto f = quux ();	// { dg-error "quux" }
diff --git a/gcc/testsuite/g++.dg/cpp2a/inline-asm3.C b/gcc/testsuite/g++.dg/cpp2a/inline-asm3.C
index a7476b1d9d1a..a6f612e2447e 100644
--- a/gcc/testsuite/g++.dg/cpp2a/inline-asm3.C
+++ b/gcc/testsuite/g++.dg/cpp2a/inline-asm3.C
@@ -9,4 +9,4 @@ foo ()
  return i;
 }
 
-constexpr int i = foo ();
+constexpr int i = foo ();	// { dg-error "foo" }