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);
in the enclosed v5 patch?
>
> Others LGTM.
> > op = gen_int_mode (INTVAL (src), mode);
> > *insn_p = nullptr;
> > }
>
--
H.J.
From 3cad238b5b55b125a85b2c6761bc3a2de0c7700c Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <[email protected]>
Date: Mon, 9 Mar 2026 06:16:24 -0700
Subject: [PATCH v5] x86: Handle non-int load with integer constant
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 | 38 +++++++++++++++++++---
gcc/testsuite/gcc.target/i386/pr124407-1.c | 17 ++++++++++
gcc/testsuite/gcc.target/i386/pr124407-2.c | 12 +++++++
3 files changed, 62 insertions(+), 5 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..f95f30f84cd 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)
@@ -3777,8 +3800,13 @@ 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))
- op = gen_int_mode (INTVAL (src), mode);
+ 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);
*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..41ffe5e24d5
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr124407-1.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-options "-Ofast -msse2 -fdump-rtl-x86_cse" } */
+
+typedef __attribute__((__vector_size__(8))) float V;
+V v;
+
+void
+foo()
+{
+ int i;
+ float f;
+ __builtin_memcpy(&f, &i, 1);
+ v -= f;
+ v /= f;
+}
+
+/* { dg-final { scan-rtl-dump {\(const_double:SF 0.0 \[0x0.0p\+0\]\)} "x86_cse" { target { ! ia32 } } } } */
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
