On Thu, 8 Oct 2026, Igor Shevlyakov wrote:
> When vectorizable_simd_clone_call uses an inbranch SIMD clone for a call
> site that is not masked, it synthesizes an all-true mask. For clones
> whose mask argument is a vector of the argument type (mask_mode ==
> VOIDmode) it built an all-ones mask of that type and then converted it
> to the clone's 1/0 encoding with
>
> VEC_COND_EXPR <mask, { 1, ... }, { 0, ... }>
>
> A VEC_COND_EXPR condition must be a boolean vector, but
> vect_build_all_ones_mask returns one only when the mask type is
> boolean; for a floating-point mask type it is a vector of NaNs, and the
> statement is invalid GIMPLE. On x86_64 the SSE clone takes its mask as
> vector(2) double; since r17-2654 two calls of an "omp declare simd
> inbranch" function can be SLP-vectorized as one unmasked call of that
> clone, so this ICEs at -O2 -fopenmp-simd.
>
> All lanes are active, so pass the value the VEC_COND_EXPR would select,
> a vector of 1s, directly.
How did you test the patch?
OK if bootstrapped/tested.
Thanks,
Richard.
> PR tree-optimization/127784
>
> gcc/ChangeLog:
>
> * tree-vect-stmts.cc (vectorizable_simd_clone_call): Pass a vector
> of 1s as an all-true mask for a VOIDmode mask_mode.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/vect/vect-simd-clone-allones-mask.c: New test.
>
> Signed-off-by: Igor Shevlyakov <[email protected]>
> ---
> Bootstrapped and regtested on x86_64-pc-linux-gnu (-m32/-m64), no new
> regressions.
>
> .../vect/vect-simd-clone-allones-mask.c | 43 +++++++++++++++++++
> gcc/tree-vect-stmts.cc | 8 ++++
> 2 files changed, 51 insertions(+)
> create mode 100644 gcc/testsuite/gcc.dg/vect/vect-simd-clone-allones-mask.c
>
> diff --git a/gcc/testsuite/gcc.dg/vect/vect-simd-clone-allones-mask.c
> b/gcc/testsuite/gcc.dg/vect/vect-simd-clone-allones-mask.c
> new file mode 100644
> index 00000000000..d74e9246168
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/vect/vect-simd-clone-allones-mask.c
> @@ -0,0 +1,43 @@
> +/* Unmasked call of an inbranch SIMD clone whose mask argument is a
> + floating-point vector. */
> +/* { dg-require-effective-target vect_simd_clones } */
> +/* { dg-additional-options "-fopenmp-simd --param
> vect-partial-vector-usage=0" } */
> +/* { dg-additional-options "-mavx512f" { target avx512f_runtime } } */
> +
> +#include "tree-vect.h"
> +
> +#define N 64
> +
> +#pragma omp declare simd inbranch
> +__attribute__((noinline)) double
> +foo (double x, double y)
> +{
> + return x * 10.0 + y;
> +}
> +
> +double r[N], t[N];
> +
> +__attribute__((noipa)) void
> +f (double *rp, double *tp, long n)
> +{
> + for (long i = 0; i < n; i++)
> + rp[i] = rp[i] * (foo (tp[0] + 1.0, tp[0] + 2.0)
> + + foo (tp[0] + 3.0, tp[0] + 4.0));
> +}
> +
> +int
> +main ()
> +{
> + check_vect ();
> + for (int i = 0; i < N; i++)
> + {
> + r[i] = i;
> + t[i] = 0.5;
> + }
> + f (r, t, N);
> + /* foo (1.5, 2.5) + foo (3.5, 4.5) = 17.5 + 39.5. */
> + for (int i = 0; i < N; i++)
> + if (r[i] != i * 57.0)
> + __builtin_abort ();
> + return 0;
> +}
> diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
> index 18d0dd8ff3a..fd87bdab684 100644
> --- a/gcc/tree-vect-stmts.cc
> +++ b/gcc/tree-vect-stmts.cc
> @@ -4903,6 +4903,14 @@ vectorizable_simd_clone_call (vec_info *vinfo,
> stmt_vec_info stmt_info,
> mask = vect_get_loop_mask (loop_vinfo, gsi, loop_masks,
> ncopies * o, mask_vectype, m);
> }
> + else if (bestn->simdclone->mask_mode == VOIDmode)
> + {
> + /* All lanes are active: pass what the VEC_COND_EXPR below
> + would select. An all-ones floating-point MASK_ARGTYPE
> + is not a valid condition. */
> + vargs.safe_push (build_one_cst (mask_argtype));
> + continue;
> + }
> else
> mask = vect_build_all_ones_mask (vinfo, stmt_info,
> mask_argtype);
>
--
Richard Biener <[email protected]>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Stefan Gaiser, Jochen Jaser, Abhinav Puri; (HRB 36809, AG Nuernberg)
