On 3/5/25 12:09 PM, Marek Polacek wrote:
On Tue, Mar 04, 2025 at 05:34:10PM -0500, Jason Merrill wrote:
On 2/11/25 6:24 PM, Marek Polacek wrote:
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?

-- >8 --
Here we ICE since r11-7740 because we no longer say that (long)&a
(where a is a global var) is non_constant_p.  So VERIFY_CONSTANT
does not return and we crash on tree_to_uhwi.  We should check
tree_fits_uhwi_p before calling tree_to_uhwi.

        PR c++/118775

gcc/cp/ChangeLog:

        * constexpr.cc (cxx_eval_call_expression): Check tree_fits_uhwi_p.

gcc/testsuite/ChangeLog:

        * g++.dg/cpp2a/constexpr-new24.C: New test.
        * g++.dg/cpp2a/constexpr-new25.C: New test.
---
   gcc/cp/constexpr.cc                          |  7 +++++
   gcc/testsuite/g++.dg/cpp2a/constexpr-new24.C | 25 ++++++++++++++++++
   gcc/testsuite/g++.dg/cpp2a/constexpr-new25.C | 27 ++++++++++++++++++++
   3 files changed, 59 insertions(+)
   create mode 100644 gcc/testsuite/g++.dg/cpp2a/constexpr-new24.C
   create mode 100644 gcc/testsuite/g++.dg/cpp2a/constexpr-new25.C

diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc
index f142dd32bc8..f8f9a9df1a2 100644
--- a/gcc/cp/constexpr.cc
+++ b/gcc/cp/constexpr.cc
@@ -2909,6 +2909,13 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree 
t,
          gcc_assert (arg0);
          if (new_op_p)
            {
+             if (!tree_fits_uhwi_p (arg0))
+               {
+                 if (!ctx->quiet)
+                   error_at (loc, "cannot allocate array: size too large");

"too large" seems misleading in this case, where it just isn't a
compile-time constant.

Fair, how about "size not constant"?
Why didn't the VERIFY_CONSTANT just above already reject this?

This is about *non_constant_p.  Since r11-7740 cxx_eval_constant_expression
returns early less often:

@@ -6656,7 +6656,8 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, 
tree t,

     if (TREE_CODE (t) == CONVERT_EXPR
         && ARITHMETIC_TYPE_P (type)
-       && INDIRECT_TYPE_P (TREE_TYPE (op)))
+       && INDIRECT_TYPE_P (TREE_TYPE (op))
+       && ctx->manifestly_const_eval)

Aha.  I think this should check ctx->strict instead of
ctx->manifestly_const_eval.

Jason

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