Hongtao Liu via Gcc-patches <gcc-patches@gcc.gnu.org> writes:
> Hi:
> If SRC had been assigned a mode narrower than the copy, we can't link
> DEST into the chain even they have same
> hard_regno_nregs(i.e. HImode/SImode in i386 backend).
In general, changes between modes within the same hard register are OK.
Could you explain in more detail what's going wrong?
Thanks,
Richard
>
> i.e
> kmovw %k0, %edi
> vmovd %edi, %xmm2
> vpshuflw $0, %xmm2, %xmm0
> kmovw %k0, %r8d
> kmovd %k0, %r9d
> ...
> - movl %r9d, %r11d
> + vmovd %xmm2, %r11d
>
> Bootstrap and regtested on x86_64-linux-gnu{-m32,}.
> Ok for trunk?
>
> gcc/ChangeLog:
>
> PR rtl-optimization/98694
> * regcprop.c (copy_value): If SRC had been assigned a mode
> narrower than the copy, we can't link DEST into the chain even
> they have same hard_regno_nregs(i.e. HImode/SImode in i386
> backend).
>
> gcc/testsuite/ChangeLog:
>
> PR rtl-optimization/98694
> * gcc.target/i386/pr98694.c: New test.
>
> ---
> gcc/regcprop.c | 3 +-
> gcc/testsuite/gcc.target/i386/pr98694.c | 38 +++++++++++++++++++++++++
> 2 files changed, 40 insertions(+), 1 deletion(-)
> create mode 100644 gcc/testsuite/gcc.target/i386/pr98694.c
>
> diff --git a/gcc/regcprop.c b/gcc/regcprop.c
> index dd62cb36013..997516eca07 100644
> --- a/gcc/regcprop.c
> +++ b/gcc/regcprop.c
> @@ -355,7 +355,8 @@ copy_value (rtx dest, rtx src, struct value_data *vd)
> /* If SRC had been assigned a mode narrower than the copy, we can't
> link DEST into the chain, because not all of the pieces of the
> copy came from oldest_regno. */
> - else if (sn > hard_regno_nregs (sr, vd->e[sr].mode))
> + else if (sn > hard_regno_nregs (sr, vd->e[sr].mode)
> + || partial_subreg_p (vd->e[sr].mode, GET_MODE (src)))
> return;
>
> /* Link DR at the end of the value chain used by SR. */
> diff --git a/gcc/testsuite/gcc.target/i386/pr98694.c
> b/gcc/testsuite/gcc.target/i386/pr98694.c
> new file mode 100644
> index 00000000000..611f9e77627
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr98694.c
> @@ -0,0 +1,38 @@
> +/* PR rtl-optimization/98694 */
> +/* { dg-do run { target { ! ia32 } } } */
> +/* { dg-options "-O2 -mavx512bw" } */
> +/* { dg-require-effective-target avx512bw } */
> +
> +#include<immintrin.h>
> +typedef short v4hi __attribute__ ((vector_size (8)));
> +typedef int v2si __attribute__ ((vector_size (8)));
> +v4hi b;
> +
> +__attribute__ ((noipa))
> +v2si
> +foo (__m512i src1, __m512i src2)
> +{
> + __mmask64 m = _mm512_cmpeq_epu8_mask (src1, src2);
> + short s = (short) m;
> + int i = (int)m;
> + b = __extension__ (v4hi) {s, s, s, s};
> + return __extension__ (v2si) {i, i};
> +}
> +
> +int main ()
> +{
> + __m512i src1 = _mm512_setzero_si512 ();
> + __m512i src2 = _mm512_set_epi8 (0, 1, 0, 1, 0, 1, 0, 1,
> + 0, 1, 0, 1, 0, 1, 0, 1,
> + 0, 1, 0, 1, 0, 1, 0, 1,
> + 0, 1, 0, 1, 0, 1, 0, 1,
> + 0, 1, 0, 1, 0, 1, 0, 1,
> + 0, 1, 0, 1, 0, 1, 0, 1,
> + 0, 1, 0, 1, 0, 1, 0, 1,
> + 0, 1, 0, 1, 0, 1, 0, 1);
> + __mmask64 m = _mm512_cmpeq_epu8_mask (src1, src2);
> + v2si a = foo (src1, src2);
> + if (a[0] != (int)m)
> + __builtin_abort ();
> + return 0;
> +}
> --
