> Am 05.07.2025 um 17:41 schrieb Andrew Pinski <quic_apin...@quicinc.com>:
>
> The cdce code introduces a test for a NaN using the EQ_EXPR code.
> The problem is EQ_EXPR can cause an exception with non-call exceptions
> and signaling nans turned on. This is now correctly rejected by the verfier
> since r16-241-g4c40e3d7b9152f.
> The fix is seperate out the comparison into its own statement from the
> GIMPLE_COND.
>
> Bootstrapped and tested on x86_64-linux-gnu with no regressions.
Ok
Richard
> PR tree-optimization/120951
>
> gcc/ChangeLog:
>
> * tree-call-cdce.cc (use_internal_fn): For non-call exceptions
> with EQ_EXPR can throw for floating point types, then create
> the EQ_EXPR seperately.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/torture/pr120951-1.c: New test.
>
> Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
> ---
> gcc/testsuite/gcc.dg/torture/pr120951-1.c | 12 ++++++++++++
> gcc/tree-call-cdce.cc | 17 +++++++++++++++--
> 2 files changed, 27 insertions(+), 2 deletions(-)
> create mode 100644 gcc/testsuite/gcc.dg/torture/pr120951-1.c
>
> diff --git a/gcc/testsuite/gcc.dg/torture/pr120951-1.c
> b/gcc/testsuite/gcc.dg/torture/pr120951-1.c
> new file mode 100644
> index 00000000000..4e2b41deb52
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/torture/pr120951-1.c
> @@ -0,0 +1,12 @@
> +/* { dg-do compile } */
> +/* { dg-options "-fnon-call-exceptions -fsignaling-nans" } */
> +
> +/* PR tree-optimization/120951 */
> +
> +/* cdce would create a trapping comparison inside a condition.
> + tests to make sure that does not happen. */
> +
> +double f(double r, double i) {
> + return __builtin_fmod(r, i);
> +}
> +
> diff --git a/gcc/tree-call-cdce.cc b/gcc/tree-call-cdce.cc
> index 649c1e2b9f9..3edea754ee4 100644
> --- a/gcc/tree-call-cdce.cc
> +++ b/gcc/tree-call-cdce.cc
> @@ -36,6 +36,7 @@ along with GCC; see the file COPYING3. If not see
> #include "builtins.h"
> #include "internal-fn.h"
> #include "tree-dfa.h"
> +#include "tree-eh.h"
>
>
> /* This pass serves two closely-related purposes:
> @@ -1222,8 +1223,20 @@ use_internal_fn (gcall *call)
> {
> /* Skip the call if LHS == LHS. If we reach here, EDOM is the only
> valid errno value and it is used iff the result is NaN. */
> - conds.quick_push (gimple_build_cond (EQ_EXPR, lhs, lhs,
> - NULL_TREE, NULL_TREE));
> + /* In the case of non call exceptions, with signaling NaNs, EQ_EXPR
> + can throw an exception and that can't be part of the GIMPLE_COND. */
> + if (flag_exceptions
> + && cfun->can_throw_non_call_exceptions
> + && operation_could_trap_p (EQ_EXPR, true, false, NULL_TREE))
> + {
> + tree b = make_ssa_name (boolean_type_node);
> + conds.quick_push (gimple_build_assign (b, EQ_EXPR, lhs, lhs));
> + conds.quick_push (gimple_build_cond (NE_EXPR, b, boolean_false_node,
> + NULL_TREE, NULL_TREE));
> + }
> + else
> + conds.quick_push (gimple_build_cond (EQ_EXPR, lhs, lhs,
> + NULL_TREE, NULL_TREE));
> nconds++;
>
> /* Try replacing the original call with a direct assignment to
> --
> 2.43.0
>
