On Fri, Aug 09, 2024 at 09:49:03AM +0200, Stefan Schulze Frielinghaus wrote:
> On Thu, Aug 08, 2024 at 01:56:48PM -0600, Jeff Law wrote:
> > > I haven't tested it extensively but it triggers at least for the current
> > > case.
> > > I would have loved to also print the insn but couldn't figure out how to
> > > ICE
> > > and stringify an insn. I will have a look at this tomorrow. Did you
> > > have any
> > > place in mind where to put/call something like this?
> > I didn't have anywhere specific in mind. As I suspected the
> > verify_rtl_sharing isn't a great fit from an implementation standpoint, but
> > it seems right conceptually.
>
> Right and since we are walking over all insns there anyway we could also
> check pseudos on the go. I didn't want to rename verify_rtl_sharing()
> since this is publicly visible but renamed verify_insn_sharing() into
> verify_insn_sharing_and_pseudo_references() to reflect the additional
> work---although the name is bit of a mouthful.
>
> > If you want to throw a patch over the wall for testing, happy to put it into
> > my tester and see what comes out the other side. I wouldn't be at all
> > surprised if it tripped on other targets.
>
> Having more testing would be great. I've attached a new patch.
Out of curiosity, did you have any chance to run the patch in your
tester? If there is no fallout, i.e., no target is immediately
affected, I would be happy to post the patch.
Cheers,
Stefan
> From 0199088d2877c9c840ce984f61365816879818bc Mon Sep 17 00:00:00 2001
> From: Stefan Schulze Frielinghaus <stefa...@gcc.gnu.org>
> Date: Fri, 9 Aug 2024 09:45:57 +0200
> Subject: [PATCH] rtl: Verify pseudo register references
>
> Ensure that each pseudo register referenced in an insn equals its
> definition. In particular this means that we error out if a pseudo
> register is referenced in a different mode.
> ---
> gcc/emit-rtl.cc | 37 +++++++++++++++++++++++++++++++++----
> 1 file changed, 33 insertions(+), 4 deletions(-)
>
> diff --git a/gcc/emit-rtl.cc b/gcc/emit-rtl.cc
> index cb04aa1a8c6..00af73ca219 100644
> --- a/gcc/emit-rtl.cc
> +++ b/gcc/emit-rtl.cc
> @@ -3122,16 +3122,45 @@ reset_all_used_flags (void)
> }
> }
>
> -/* Verify sharing in INSN. */
> +/* Verify that each pseudo register referenced in INSN equals its definition.
> + For example, error out if modes do not coincide. */
>
> static void
> -verify_insn_sharing (rtx insn)
> +verify_rtl_pseudo_references (rtx insn)
> +{
> + subrtx_iterator::array_type array;
> + FOR_EACH_SUBRTX (iter, array, PATTERN (insn), NONCONST)
> + {
> + const_rtx reg = *iter;
> + if (!reg || !REG_P (reg))
> + continue;
> + int regno = REGNO (reg);
> + /* Hard registers may be referenced in different modes. */
> + if (HARD_REGISTER_NUM_P (regno))
> + continue;
> + const_rtx orig_reg = regno_reg_rtx[regno];
> + if (!rtx_equal_p (reg, orig_reg))
> + {
> + error ("pseudo register");
> + debug_rtx (orig_reg);
> + error ("does not coincide with its reference in insn");
> + debug_rtx (insn);
> + internal_error ("internal consistency failure");
> + }
> + }
> +}
> +
> +/* Verify sharing and pseudo references in INSN. */
> +
> +static void
> +verify_insn_sharing_and_pseudo_references (rtx insn)
> {
> gcc_assert (INSN_P (insn));
> verify_rtx_sharing (PATTERN (insn), insn);
> verify_rtx_sharing (REG_NOTES (insn), insn);
> if (CALL_P (insn))
> verify_rtx_sharing (CALL_INSN_FUNCTION_USAGE (insn), insn);
> + verify_rtl_pseudo_references (insn);
> }
>
> /* Go through all the RTL insn bodies and check that there is no unexpected
> @@ -3151,13 +3180,13 @@ verify_rtl_sharing (void)
> {
> rtx pat = PATTERN (p);
> if (GET_CODE (pat) != SEQUENCE)
> - verify_insn_sharing (p);
> + verify_insn_sharing_and_pseudo_references (p);
> else
> for (int i = 0; i < XVECLEN (pat, 0); i++)
> {
> rtx insn = XVECEXP (pat, 0, i);
> if (INSN_P (insn))
> - verify_insn_sharing (insn);
> + verify_insn_sharing_and_pseudo_references (insn);
> }
> }
>
> --
> 2.45.2
>
