Andrew Pinski <quic_apin...@quicinc.com> writes:
> Early-RA was considering throwing instructions as being dead and removing
> them even if -fno-delete-dead-exceptions was in use. This fixes that
> oversight.
>
> Built and tested for aarch64-linux-gnu.
>
> PR target/116927
>
> gcc/ChangeLog:
>
> * config/aarch64/aarch64-early-ra.cc (early_ra::is_dead_insn): Insns
> that throw are not dead with -fno-delete-dead-exceptions.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/torture/pr116927-1.C: New test.
OK, thanks.
I don't like these magic flags that every relevant pass has to remember
to check individually. In practice, the only way they will be checked
is if code is copied-and-pasted between passes (meaning an abstraction
is missing) or by trial and error.
I couldn't find an obvious helper routine for it, though, so I agree
this is the established best practice.
Richard
>
> Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
> ---
> gcc/config/aarch64/aarch64-early-ra.cc | 6 ++++++
> gcc/testsuite/g++.dg/torture/pr116927-1.C | 15 +++++++++++++++
> 2 files changed, 21 insertions(+)
> create mode 100644 gcc/testsuite/g++.dg/torture/pr116927-1.C
>
> diff --git a/gcc/config/aarch64/aarch64-early-ra.cc
> b/gcc/config/aarch64/aarch64-early-ra.cc
> index 5f269d029b4..6e544dd6191 100644
> --- a/gcc/config/aarch64/aarch64-early-ra.cc
> +++ b/gcc/config/aarch64/aarch64-early-ra.cc
> @@ -3389,6 +3389,12 @@ early_ra::is_dead_insn (rtx_insn *insn)
> if (side_effects_p (set))
> return false;
>
> + /* If we can't delete dead exceptions and the insn throws,
> + then the instruction is not dead. */
> + if (!cfun->can_delete_dead_exceptions
> + && !insn_nothrow_p (insn))
> + return false;
> +
> return true;
> }
>
> diff --git a/gcc/testsuite/g++.dg/torture/pr116927-1.C
> b/gcc/testsuite/g++.dg/torture/pr116927-1.C
> new file mode 100644
> index 00000000000..22fa1dbd7e1
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/torture/pr116927-1.C
> @@ -0,0 +1,15 @@
> +// { dg-do compile }
> +// { dg-additional-options "-fnon-call-exceptions
> -fno-delete-dead-exceptions" }
> +
> +// PR target/116927
> +// aarch64's Early ra was removing possiblely trapping
> +// floating point insn
> +
> +void
> +foo (float f)
> +{
> + try {
> + f ++;
> + }catch(...)
> + {}
> +}
