Jennifer Schmitz <jschm...@nvidia.com> writes:
> [PATCH] [PR120276] regcprop: Return from copy_value for unordered modes
>
> The ICE in PR120276 resulted from a comparison of VNx4QI and V8QI using
> partial_subreg_p in the function copy_value during the RTL pass
> regcprop, failing the assertion in
>
> inline bool
> partial_subreg_p (machine_mode outermode, machine_mode innermode)
> {
> /* Modes involved in a subreg must be ordered. In particular, we must
> always know at compile time whether the subreg is paradoxical. */
> poly_int64 outer_prec = GET_MODE_PRECISION (outermode);
> poly_int64 inner_prec = GET_MODE_PRECISION (innermode);
> gcc_checking_assert (ordered_p (outer_prec, inner_prec));
> return maybe_lt (outer_prec, inner_prec);
> }
>
> Returning from the function if the modes are not ordered before reaching
> the call to partial_subreg_p resolves the ICE and passes bootstrap and
> testing without regression.
> OK for mainline?
>
> Signed-off-by: Jennifer Schmitz <jschm...@nvidia.com>
>
> gcc/
> PR middle-end/120276
> * regcprop.cc (copy_value): Return in case of unordered modes.
>
> gcc/testsuite/
> PR middle-end/120276
> * gcc.dg/torture/pr120276.c: New test.
OK, thanks.
Richard
> ---
> gcc/regcprop.cc | 4 ++++
> gcc/testsuite/gcc.dg/torture/pr120276.c | 20 ++++++++++++++++++++
> 2 files changed, 24 insertions(+)
> create mode 100644 gcc/testsuite/gcc.dg/torture/pr120276.c
>
> diff --git a/gcc/regcprop.cc b/gcc/regcprop.cc
> index 4fa1305526c..98ab3f77e83 100644
> --- a/gcc/regcprop.cc
> +++ b/gcc/regcprop.cc
> @@ -332,6 +332,10 @@ copy_value (rtx dest, rtx src, struct value_data *vd)
> if (vd->e[sr].mode == VOIDmode)
> set_value_regno (sr, vd->e[dr].mode, vd);
>
> + else if (!ordered_p (GET_MODE_PRECISION (vd->e[sr].mode),
> + GET_MODE_PRECISION (GET_MODE (src))))
> + return;
> +
> /* If we are narrowing the input to a smaller number of hard regs,
> and it is in big endian, we are really extracting a high part.
> Since we generally associate a low part of a value with the value
> itself,
> diff --git a/gcc/testsuite/gcc.dg/torture/pr120276.c
> b/gcc/testsuite/gcc.dg/torture/pr120276.c
> new file mode 100644
> index 00000000000..9717a7103e5
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/torture/pr120276.c
> @@ -0,0 +1,20 @@
> +/* { dg-do compile } */
> +/* { dg-additional-options "-march=armv8.2-a+sve" { target aarch64*-*-* } }
> */
> +
> +int a;
> +char b[1];
> +int c[18];
> +void d(char *);
> +void e() {
> + int f;
> + char *g;
> + a = 0;
> + for (; a < 18; a++) {
> + int h = f = 0;
> + for (; f < 4; f++) {
> + g[a * 4 + f] = c[a] >> h;
> + h += 8;
> + }
> + }
> + d(b);
> +}
> \ No newline at end of file
