c++: ICE with reinterpret_cast and switch [PR113545]
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Commit Message
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
-- >8 --
Jason, this is the patch you proposed for PR113545. It looks very safe
so I'm posting it here so that it's not forgotten.
PR c++/113545
gcc/cp/ChangeLog:
* constexpr.cc (cxx_eval_switch_expr): If the condition doesn't reduce
to an INTEGER_CST, consider it non-constant.
gcc/testsuite/ChangeLog:
* g++.dg/cpp1y/constexpr-reinterpret3.C: Remove dg-ice.
---
gcc/cp/constexpr.cc | 10 ++++++++++
gcc/testsuite/g++.dg/cpp1y/constexpr-reinterpret3.C | 4 +---
2 files changed, 11 insertions(+), 3 deletions(-)
base-commit: 93e1559bea434a681208e5e7a21513d7da2844d6
prerequisite-patch-id: 9dda211bd29817f18d2d46c3c5a7bbe3708cf9f2
Comments
On 2/10/24 17:42, Marek Polacek wrote:
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
OK, thanks.
> -- >8 --
> Jason, this is the patch you proposed for PR113545. It looks very safe
> so I'm posting it here so that it's not forgotten.
>
> PR c++/113545
>
> gcc/cp/ChangeLog:
>
> * constexpr.cc (cxx_eval_switch_expr): If the condition doesn't reduce
> to an INTEGER_CST, consider it non-constant.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp1y/constexpr-reinterpret3.C: Remove dg-ice.
> ---
> gcc/cp/constexpr.cc | 10 ++++++++++
> gcc/testsuite/g++.dg/cpp1y/constexpr-reinterpret3.C | 4 +---
> 2 files changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc
> index 2ebb1470dd5..fa346fe01c9 100644
> --- a/gcc/cp/constexpr.cc
> +++ b/gcc/cp/constexpr.cc
> @@ -7106,6 +7106,16 @@ cxx_eval_switch_expr (const constexpr_ctx *ctx, tree t,
> cond = cxx_eval_constant_expression (ctx, cond, vc_prvalue,
> non_constant_p, overflow_p);
> VERIFY_CONSTANT (cond);
> + if (TREE_CODE (cond) != INTEGER_CST)
> + {
> + /* If the condition doesn't reduce to an INTEGER_CST it isn't a usable
> + switch condition even if it's constant enough for other things
> + (c++/113545). */
> + gcc_checking_assert (ctx->quiet);
> + *non_constant_p = true;
> + return t;
> + }
> +
> *jump_target = cond;
>
> tree body
> diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-reinterpret3.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-reinterpret3.C
> index 51feb2e558e..adc0b418df9 100644
> --- a/gcc/testsuite/g++.dg/cpp1y/constexpr-reinterpret3.C
> +++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-reinterpret3.C
> @@ -1,7 +1,5 @@
> // PR c++/113545
> -// { dg-do compile { target c++14 } }
> -// Please change the above "dg-do compile" to "dg-do run" when the ICE is resolved.
> -// { dg-ice "PR112545 - constexpr function with switch called for reinterpret_cast" }
> +// { dg-do run { target c++14 } }
>
> char foo;
>
>
> base-commit: 93e1559bea434a681208e5e7a21513d7da2844d6
> prerequisite-patch-id: 9dda211bd29817f18d2d46c3c5a7bbe3708cf9f2
@@ -7106,6 +7106,16 @@ cxx_eval_switch_expr (const constexpr_ctx *ctx, tree t,
cond = cxx_eval_constant_expression (ctx, cond, vc_prvalue,
non_constant_p, overflow_p);
VERIFY_CONSTANT (cond);
+ if (TREE_CODE (cond) != INTEGER_CST)
+ {
+ /* If the condition doesn't reduce to an INTEGER_CST it isn't a usable
+ switch condition even if it's constant enough for other things
+ (c++/113545). */
+ gcc_checking_assert (ctx->quiet);
+ *non_constant_p = true;
+ return t;
+ }
+
*jump_target = cond;
tree body
@@ -1,7 +1,5 @@
// PR c++/113545
-// { dg-do compile { target c++14 } }
-// Please change the above "dg-do compile" to "dg-do run" when the ICE is resolved.
-// { dg-ice "PR112545 - constexpr function with switch called for reinterpret_cast" }
+// { dg-do run { target c++14 } }
char foo;