On Mon, Dec 6, 2021 at 4:41 AM liuhongt via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> When moves between integer and sse registers are cheap.
>
> 2021-12-06 Hongtao Liu <hongtao....@intel.com>
> Uroš Bizjak <ubiz...@gmail.com>
> gcc/ChangeLog:
>
> PR target/95740
> * config/i386/i386.c (ix86_preferred_reload_class): Allow
> integer regs when moves between register units are cheap.
> * config/i386/i386.h (INT_SSE_CLASS_P): New.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.target/i386/pr95740.c: New test.
OK.
Thanks,
Uros.
> ---
> gcc/config/i386/i386.c | 12 ++++++++++--
> gcc/config/i386/i386.h | 2 ++
> gcc/testsuite/gcc.target/i386/pr95740.c | 26 +++++++++++++++++++++++++
> 3 files changed, 38 insertions(+), 2 deletions(-)
> create mode 100644 gcc/testsuite/gcc.target/i386/pr95740.c
>
> diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
> index 80fee627358..e3c2e294988 100644
> --- a/gcc/config/i386/i386.c
> +++ b/gcc/config/i386/i386.c
> @@ -19194,9 +19194,17 @@ ix86_preferred_reload_class (rtx x, reg_class_t
> regclass)
> return NO_REGS;
> }
>
> - /* Prefer SSE regs only, if we can use them for math. */
> + /* Prefer SSE if we can use them for math. Also allow integer regs
> + when moves between register units are cheap. */
> if (SSE_FLOAT_MODE_P (mode) && TARGET_SSE_MATH)
> - return SSE_CLASS_P (regclass) ? regclass : NO_REGS;
> + {
> + if (TARGET_INTER_UNIT_MOVES_FROM_VEC
> + && TARGET_INTER_UNIT_MOVES_TO_VEC
> + && GET_MODE_SIZE (mode) <= GET_MODE_SIZE (word_mode))
> + return INT_SSE_CLASS_P (regclass) ? regclass : NO_REGS;
> + else
> + return SSE_CLASS_P (regclass) ? regclass : NO_REGS;
> + }
>
> /* Generally when we see PLUS here, it's the function invariant
> (plus soft-fp const_int). Which can only be computed into general
> diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h
> index 2fda1e0686e..ec90e47904b 100644
> --- a/gcc/config/i386/i386.h
> +++ b/gcc/config/i386/i386.h
> @@ -1283,6 +1283,8 @@ enum reg_class
> reg_class_subset_p ((CLASS), FLOAT_REGS)
> #define SSE_CLASS_P(CLASS) \
> reg_class_subset_p ((CLASS), ALL_SSE_REGS)
> +#define INT_SSE_CLASS_P(CLASS) \
> + reg_class_subset_p ((CLASS), INT_SSE_REGS)
> #define MMX_CLASS_P(CLASS) \
> ((CLASS) == MMX_REGS)
> #define MASK_CLASS_P(CLASS) \
> diff --git a/gcc/testsuite/gcc.target/i386/pr95740.c
> b/gcc/testsuite/gcc.target/i386/pr95740.c
> new file mode 100644
> index 00000000000..7ecd71ba8c1
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr95740.c
> @@ -0,0 +1,26 @@
> +/* { dg-do compile { target { ! ia32 } } } */
> +/* { dg-options "-msse2 -O2 -mtune=generic -mtune-ctrl=use_incdec -masm=att
> -mfpmath=sse" } */
> +/* { dg-final { scan-assembler-times {(?n)movd[\t ]*%xmm0.*%eax} 1 } } */
> +/* { dg-final { scan-assembler-times {(?n)incl[\t ]*%eax} 1 } } */
> +/* { dg-final { scan-assembler-times {(?n)movq[\t ]*%xmm0.*%rax} 1 } } */
> +/* { dg-final { scan-assembler-times {(?n)incq[\t ]*%rax} 1 } } */
> +
> +int
> +foo (float a)
> +{
> + union{
> + int b;
> + float a;}u;
> + u.a = a;
> + return u.b + 1;
> +}
> +
> +long long
> +foo1 (double a)
> +{
> + union{
> + long long b;
> + double a;}u;
> + u.a = a;
> + return u.b + 1;
> +}
> --
> 2.18.2
>
