On Tue, Mar 18, 2025 at 04:19:12PM -0400, Jason Merrill wrote:
> On 3/18/25 3:12 PM, Marek Polacek wrote:
> > On Tue, Mar 18, 2025 at 03:05:57PM -0400, Patrick Palka wrote:
> > > On Tue, 18 Mar 2025, Marek Polacek wrote:
> > > 
> > > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk/14?
> > > > 
> > > > -- >8 --
> > > > This ICE appeared with the removal of NON_DEPENDENT_EXPR.  Previously
> > > > skip_simple_arithmetic would get NON_DEPENDENT_EXPR<CAST_EXPR<>> and
> > > > since NON_DEPENDENT_EXPR is neither BINARY_CLASS_P nor UNARY_CLASS_P,
> > > > there was no problem.  But now we pass just CAST_EXPR<> and a CAST_EXPR
> > > > is a tcc_unary, so we extract its null operand and crash.
> > > > 
> > > > skip_simple_arithmetic is called from save_expr.  cp_save_expr already
> > > > avoids calling save_expr in a template, so that seems like an 
> > > > appropriate
> > > > way to fix this.
> > > > 
> > > >         PR c++/119344
> > > > 
> > > > gcc/cp/ChangeLog:
> > > > 
> > > >         * typeck.cc (cp_build_binary_op): Use cp_save_expr instead of 
> > > > save_expr.
> > > > 
> > > > gcc/testsuite/ChangeLog:
> > > > 
> > > >         * g++.dg/conversion/ptrmem10.C: New test.
> > > 
> > > LGTM.  I'm surprised the CAST_EXPR for 'T()' has TREE_SIDE_EFFECTS set
> > > here, since it's just value initialization of scalar type.
> > 
> > Thanks for taking a look.  The TREE_SIDE_EFFECTS comes from:
> > 
> >        t = build_min (CAST_EXPR, type, parms);
> >        /* We don't know if it will or will not have side effects.  */
> >        TREE_SIDE_EFFECTS (t) = 1;
> > 
> > in build_functional_cast_1 where type=<record_type T>
> 
> Yep, we just don't currently bother to figure out the initialization because
> we don't need to in order to know the type of the cast.
> 
> The patch is OK, but let's go ahead and change the other uses of save_expr
> in that function as well.

Ok, here's what I'll push, thanks.

-- >8 --
This ICE appeared with the removal of NON_DEPENDENT_EXPR.  Previously
skip_simple_arithmetic would get NON_DEPENDENT_EXPR<CAST_EXPR<>> and
since NON_DEPENDENT_EXPR is neither BINARY_CLASS_P nor UNARY_CLASS_P,
there was no problem.  But now we pass just CAST_EXPR<> and a CAST_EXPR
is a tcc_unary, so we extract its null operand and crash.

skip_simple_arithmetic is called from save_expr.  cp_save_expr already
avoids calling save_expr in a template, so that seems like an appropriate
way to fix this.

        PR c++/119344

gcc/cp/ChangeLog:

        * typeck.cc (cp_build_binary_op): Use cp_save_expr instead of save_expr.

gcc/testsuite/ChangeLog:

        * g++.dg/conversion/ptrmem10.C: New test.

Reviewed-by: Patrick Palka <ppa...@redhat.com>
Reviewed-by: Jason Merrill <ja...@redhat.com>
---
 gcc/cp/typeck.cc                           | 20 ++++++++++----------
 gcc/testsuite/g++.dg/conversion/ptrmem10.C | 14 ++++++++++++++
 2 files changed, 24 insertions(+), 10 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/conversion/ptrmem10.C

diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc
index 4b382b95de1..c8e4441fb8b 100644
--- a/gcc/cp/typeck.cc
+++ b/gcc/cp/typeck.cc
@@ -5480,7 +5480,7 @@ cp_build_binary_op (const op_location_t &location,
           case stv_firstarg:
             {
               op0 = convert (TREE_TYPE (type1), op0);
-             op0 = save_expr (op0);
+             op0 = cp_save_expr (op0);
               op0 = build_vector_from_val (type1, op0);
              orig_type0 = type0 = TREE_TYPE (op0);
               code0 = TREE_CODE (type0);
@@ -5490,7 +5490,7 @@ cp_build_binary_op (const op_location_t &location,
           case stv_secondarg:
             {
               op1 = convert (TREE_TYPE (type0), op1);
-             op1 = save_expr (op1);
+             op1 = cp_save_expr (op1);
               op1 = build_vector_from_val (type0, op1);
              orig_type1 = type1 = TREE_TYPE (op1);
               code1 = TREE_CODE (type1);
@@ -6019,9 +6019,9 @@ cp_build_binary_op (const op_location_t &location,
            return error_mark_node;
 
          if (TREE_SIDE_EFFECTS (op0))
-           op0 = save_expr (op0);
+           op0 = cp_save_expr (op0);
          if (TREE_SIDE_EFFECTS (op1))
-           op1 = save_expr (op1);
+           op1 = cp_save_expr (op1);
 
          pfn0 = pfn_from_ptrmemfunc (op0);
          pfn0 = cp_fully_fold (pfn0);
@@ -6262,8 +6262,8 @@ cp_build_binary_op (const op_location_t &location,
          && !processing_template_decl
          && sanitize_flags_p (SANITIZE_POINTER_COMPARE))
        {
-         op0 = save_expr (op0);
-         op1 = save_expr (op1);
+         op0 = cp_save_expr (op0);
+         op1 = cp_save_expr (op1);
 
          tree tt = builtin_decl_explicit (BUILT_IN_ASAN_POINTER_COMPARE);
          instrument_expr = build_call_expr_loc (location, tt, 2, op0, op1);
@@ -6523,14 +6523,14 @@ cp_build_binary_op (const op_location_t &location,
            return error_mark_node;
          if (first_complex)
            {
-             op0 = save_expr (op0);
+             op0 = cp_save_expr (op0);
              real = cp_build_unary_op (REALPART_EXPR, op0, true, complain);
              imag = cp_build_unary_op (IMAGPART_EXPR, op0, true, complain);
              switch (code)
                {
                case MULT_EXPR:
                case TRUNC_DIV_EXPR:
-                 op1 = save_expr (op1);
+                 op1 = cp_save_expr (op1);
                  imag = build2 (resultcode, real_type, imag, op1);
                  /* Fall through.  */
                case PLUS_EXPR:
@@ -6543,13 +6543,13 @@ cp_build_binary_op (const op_location_t &location,
            }
          else
            {
-             op1 = save_expr (op1);
+             op1 = cp_save_expr (op1);
              real = cp_build_unary_op (REALPART_EXPR, op1, true, complain);
              imag = cp_build_unary_op (IMAGPART_EXPR, op1, true, complain);
              switch (code)
                {
                case MULT_EXPR:
-                 op0 = save_expr (op0);
+                 op0 = cp_save_expr (op0);
                  imag = build2 (resultcode, real_type, op0, imag);
                  /* Fall through.  */
                case PLUS_EXPR:
diff --git a/gcc/testsuite/g++.dg/conversion/ptrmem10.C 
b/gcc/testsuite/g++.dg/conversion/ptrmem10.C
new file mode 100644
index 00000000000..b5fc050ee81
--- /dev/null
+++ b/gcc/testsuite/g++.dg/conversion/ptrmem10.C
@@ -0,0 +1,14 @@
+// PR c++/119344
+// { dg-do compile { target c++11 } }
+
+struct S {
+    void fn();
+};
+typedef void (S::*T)(void);
+template <T Ptr>
+struct s
+{
+  static const bool t = Ptr != T();
+};
+
+int t1 = s<&S::fn>::t;

base-commit: 145c90720640ec6711ed3e5aa4152bbe1ee21751
-- 
2.48.1

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