On Sat, Sep 29, 2018 at 6:36 PM H.J. Lu <hjl.to...@gmail.com> wrote:
>
> When passing and returning BLKmode values in 2 integer registers, use
> 1 TImode register instead of 2 DImode registers. Otherwise, V1TImode
> may be used to move and store such BLKmode values, which prevent RTL
> optimizations.
>
> Tested on x86-64. OK for trunk?
>
> Thanks.
>
> H.J.
> ---
> gcc/
>
> PR target/87370
> * config/i386/i386.c (construct_container): Use TImode for
> BLKmode values in 2 integer registers.
>
> gcc/testsuite/
>
> PR target/87370
> * gcc.target/i386/pr87370.c: New test.
OK.
Thanks,
Uros.
> ---
> gcc/config/i386/i386.c | 17 +++++++++--
> gcc/testsuite/gcc.target/i386/pr87370.c | 39 +++++++++++++++++++++++++
> 2 files changed, 54 insertions(+), 2 deletions(-)
> create mode 100644 gcc/testsuite/gcc.target/i386/pr87370.c
>
> diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
> index 176cce521b7..54752513076 100644
> --- a/gcc/config/i386/i386.c
> +++ b/gcc/config/i386/i386.c
> @@ -7914,9 +7914,22 @@ construct_container (machine_mode mode, machine_mode
> orig_mode,
> if (n == 2
> && regclass[0] == X86_64_INTEGER_CLASS
> && regclass[1] == X86_64_INTEGER_CLASS
> - && (mode == CDImode || mode == TImode)
> + && (mode == CDImode || mode == TImode || mode == BLKmode)
> && intreg[0] + 1 == intreg[1])
> - return gen_rtx_REG (mode, intreg[0]);
> + {
> + if (mode == BLKmode)
> + {
> + /* Use TImode for BLKmode values in 2 integer registers. */
> + exp[0] = gen_rtx_EXPR_LIST (VOIDmode,
> + gen_rtx_REG (TImode, intreg[0]),
> + GEN_INT (0));
> + ret = gen_rtx_PARALLEL (mode, rtvec_alloc (1));
> + XVECEXP (ret, 0, 0) = exp[0];
> + return ret;
> + }
> + else
> + return gen_rtx_REG (mode, intreg[0]);
> + }
>
> /* Otherwise figure out the entries of the PARALLEL. */
> for (i = 0; i < n; i++)
> diff --git a/gcc/testsuite/gcc.target/i386/pr87370.c
> b/gcc/testsuite/gcc.target/i386/pr87370.c
> new file mode 100644
> index 00000000000..c7b6295a33b
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr87370.c
> @@ -0,0 +1,39 @@
> +/* { dg-do compile { target { ! ia32 } } } */
> +/* { dg-options "-O2" } */
> +
> +struct A
> +{
> + int b[4];
> +};
> +struct B
> +{
> + char a[12];
> + int b;
> +};
> +struct C
> +{
> + char a[16];
> +};
> +
> +struct A
> +f1 (void)
> +{
> + struct A x = {};
> + return x;
> +}
> +
> +struct B
> +f2 (void)
> +{
> + struct B x = {};
> + return x;
> +}
> +
> +struct C
> +f3 (void)
> +{
> + struct C x = {};
> + return x;
> +}
> +
> +/* { dg-final { scan-assembler-not "xmm" } } */
> --
> 2.17.1
>
