On Mon, Mar 9, 2026 at 11:02 PM Hongtao Liu <[email protected]> wrote:
>
> On Mon, Mar 9, 2026 at 9:17 PM H.J. Lu <[email protected]> wrote:
> >
> > 1. For non-int load with zero integer constant, generate:
> >
> > (set (reg/v:SF 126 [ f ])
> > (const_double:SF 0.0 [0x0.0p+0]))
> >
> > instead of
> >
> > (set (reg/v:SF 126 [ f ])
> > (const_int 0 [0]))
> >
> > 2. For non-int load with non-zero integer constant, generate:
> >
> > (set (subreg:SI (reg/v:SF 105 [ f ]) 0)
> > (const_int 1313486336 [0x4e4a3600]))
> >
> > instead of
> >
> > (set (reg/v:SF 105 [ f ])
> > (const_int 1313486336 [0x4e4a3600]))
> >
> > gcc/
> >
> > PR target/124407
> > * config/i386/i386-features.cc (ix86_place_single_vector_set):
> > Handle non-int load with integer constant.
> > (ix86_broadcast_inner): Convert const0_rtx to non-int mode.
> >
> > gcc/testsuite/
> >
> > PR target/124407
> > * gcc.target/i386/pr124407-1.c: New test.
> > * gcc.target/i386/pr124407-2.c: Likewise.
> >
> > Signed-off-by: H.J. Lu <[email protected]>
> > ---
> > gcc/config/i386/i386-features.cc | 29 +++++++++++++++++++---
> > gcc/testsuite/gcc.target/i386/pr124407-1.c | 15 +++++++++++
> > gcc/testsuite/gcc.target/i386/pr124407-2.c | 12 +++++++++
> > 3 files changed, 53 insertions(+), 3 deletions(-)
> > create mode 100644 gcc/testsuite/gcc.target/i386/pr124407-1.c
> > create mode 100644 gcc/testsuite/gcc.target/i386/pr124407-2.c
> >
> > diff --git a/gcc/config/i386/i386-features.cc
> > b/gcc/config/i386/i386-features.cc
> > index 0e4fdcd2853..155b90b50a5 100644
> > --- a/gcc/config/i386/i386-features.cc
> > +++ b/gcc/config/i386/i386-features.cc
> > @@ -3331,9 +3331,25 @@ ix86_place_single_vector_set (rtx dest, rtx src,
> > bitmap bbs,
> > rtx inner_scalar = load->val;
> > /* Set the source in (vec_duplicate:V4SI (reg:SI 99)). */
> > rtx reg = XEXP (src, 0);
> > - if ((REG_P (inner_scalar) || MEM_P (inner_scalar))
> > - && GET_MODE (reg) != GET_MODE (inner_scalar))
> > - inner_scalar = gen_rtx_SUBREG (GET_MODE (reg), inner_scalar, 0);
> > + machine_mode reg_mode = GET_MODE (reg);
> > + if (reg_mode != GET_MODE (inner_scalar))
> > + {
> > + if (REG_P (inner_scalar) || MEM_P (inner_scalar))
> > + inner_scalar = gen_rtx_SUBREG (reg_mode, inner_scalar, 0);
> > + else if (!SCALAR_INT_MODE_P (reg_mode))
> > + {
> > + /* For non-int load with integer constant, generate
> > +
> > + (set (subreg:SI (reg/v:SF 105 [ f ]) 0)
> > + (const_int 1313486336 [0x4e4a3600]))
> > +
> > + */
> > + gcc_assert (CONST_INT_P (inner_scalar));
> > + unsigned int bits = GET_MODE_BITSIZE (reg_mode);
> > + machine_mode mode = int_mode_for_size (bits, 0).require ();
> > + reg = gen_rtx_SUBREG (mode, reg, 0);
> > + }
> > + }
> > rtx set = gen_rtx_SET (reg, inner_scalar);
> > insn = emit_insn_before (set, set_insn);
> > if (dump_file)
> > @@ -3774,11 +3790,18 @@ ix86_broadcast_inner (rtx op, machine_mode mode,
> > (set (reg:V4SI 98)
> > (vec_duplicate:V4SI (reg:SI 99)))
> >
> > + and
> > +
> > + (set (subreg:SI (reg/v:SF 105 [ f ]) 0)
> > + (const_int 0 [0]))
> > +
> > Set *INSN_P to nullptr and return SET_SRC if SET_SRC is an
> > integer constant. */
> > op = src;
>
> if op is like (subreg:SF (reg:SI 100) 0), it will still generate op =
> gen_int_mode (INTVAL (src), SFmode);?
> So we need to
>
> if (op == const0_rtx && !SCALAR_INT_MODE_P (mode))
> op = CONST0_RTX (mode);
> else if (mode != GET_MODE (reg) && SCALAR_INT_MODE_P (mode))
> op = gen_int_mode (INTVAL (src), mode);
> *insn_p = nullptr;
>
> And then all other !SCALAR_INT_MODE_P (mode) cases will be handled in
> your new added code.
Fixed in the v4 patch.
Thanks.
> > if (mode != GET_MODE (reg))
> > op = gen_int_mode (INTVAL (src), mode);
> > + else if (op == const0_rtx && !SCALAR_INT_MODE_P (mode))
> > + op = CONST0_RTX (mode);
> > *insn_p = nullptr;
> > }
> > else
> > diff --git a/gcc/testsuite/gcc.target/i386/pr124407-1.c
> > b/gcc/testsuite/gcc.target/i386/pr124407-1.c
> > new file mode 100644
> > index 00000000000..7e87ab3ba57
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/pr124407-1.c
> > @@ -0,0 +1,15 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-Ofast -msse2" } */
> > +
> > +typedef __attribute__((__vector_size__(8))) float V;
> > +V v;
> > +
> > +void
> > +foo()
> > +{
> > + int i;
> > + float f;
> > + __builtin_memcpy(&f, &i, 1);
> > + v -= f;
> > + v /= f;
> > +}
> > diff --git a/gcc/testsuite/gcc.target/i386/pr124407-2.c
> > b/gcc/testsuite/gcc.target/i386/pr124407-2.c
> > new file mode 100644
> > index 00000000000..eadfce726b1
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/pr124407-2.c
> > @@ -0,0 +1,12 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-Ofast -msse2" } */
> > +
> > +__attribute__((__vector_size__(2 * sizeof(float)))) float v64f32_0;
> > +
> > +void
> > +foo0 (float f32_0)
> > +{
> > + double v128f64_0;
> > + v64f32_0 -= *(float *)__builtin_memcpy(&f32_0, &v128f64_0, 1);
> > + foo0 (848135872);
> > +}
> > --
> > 2.53.0
> >
>
>
> --
> BR,
> Hongtao
--
H.J.
