> -----Original Message-----
> From: H.J. Lu <[email protected]>
> Sent: Wednesday, March 11, 2026 11:57 AM
> To: Hongtao Liu <[email protected]>
> Cc: GCC Patches <[email protected]>; Uros Bizjak
> <[email protected]>; Liu, Hongtao <[email protected]>; Jakub Jelinek
> <[email protected]>
> Subject: [PATCH v5] x86: Handle non-int load with integer constant
>
> On Tue, Mar 10, 2026 at 5:51 PM Hongtao Liu <[email protected]> wrote:
> >
> > On Wed, Mar 11, 2026 at 3:48 AM 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 | 33 +++++++++++++++++++---
> > > gcc/testsuite/gcc.target/i386/pr124407-1.c | 17 +++++++++++
> > > gcc/testsuite/gcc.target/i386/pr124407-2.c | 12 ++++++++
> > > 3 files changed, 58 insertions(+), 4 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..49fc32d9240 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)
> > > @@ -3769,6 +3785,13 @@ ix86_broadcast_inner (rtx op, machine_mode
> mode,
> > > {
> > > /* Handle sequences like
> > >
> > > + (set (subreg:SI (reg/v:SF 105 [ f ]) 0)
> > > + (const_int 0 [0]))
> > > + (set (reg:V4SF 110)
> > > + (vec_duplicate:V4SF (reg/v:SF 105 [ f ])))
> > > +
> > > + and
> > > +
> > > (set (reg:SI 99)
> > > (const_int 34 [0x22]))
> > > (set (reg:V4SI 98)
> > > @@ -3777,7 +3800,9 @@ ix86_broadcast_inner (rtx op, machine_mode
> mode,
> > > Set *INSN_P to nullptr and return SET_SRC if SET_SRC is an
> > > integer constant. */
> > > op = src;
> > > - if (mode != GET_MODE (reg))
> > > + if (op == const0_rtx && !SCALAR_INT_MODE_P (mode))
> > > + op = CONST0_RTX (mode);
> > > + else if (mode != GET_MODE (reg))
> > should be
> >
> > else if (mode != GET_MODE (reg) && SCALAR_INT_MODE_P (mode))?
>
> How about
>
> if (SCALAR_INT_MODE_P (mode))
> {
> if (mode != GET_MODE (reg))
> op = gen_int_mode (INTVAL (src), mode);
> }
> else if (op == const0_rtx)
> op = CONST0_RTX (mode);
>
Ok.
> in the enclosed v5 patch?
>
> >
> > Others LGTM.
> > > op = gen_int_mode (INTVAL (src), mode);
> > > *insn_p = nullptr;
> > > }
> >
>
>
>
> --
> H.J.
