Re: [PATCH V4 1/4] rs6000: build constant via li;rotldi
Hi Segher,
As discussed on "~" vs. "-", "~" is correct for this patch.
I updated the patch according to Kewen's comments.
If ok, I would commit to trunk.
BR,
Jeff (Jiufu Guo)
On 2023-07-04 11:28, Kewen.Lin wrote:
Hi Jeff,
on 2023/7/4 10:18, Jiufu Guo via Gcc-patches wrote:
Hi,
If a constant is possible to be rotated to/from a positive or negative
value from "li", then "li;rotldi" can be used to build the constant.
Compare with the previous version:
https://gcc.gnu.org/pipermail/gcc-patches/2023-June/621961.html
This patch just did minor changes to the style and comments.
Bootstrap and regtest pass on ppc64{,le}.
Since the previous version is approved with conditions, this version
explained the concern too. If no objection, I would like to apply
this patch to trunk.
BR,
Jeff (Jiufu)
gcc/ChangeLog:
* config/rs6000/rs6000.cc (can_be_built_by_li_and_rotldi): New
function.
(rs6000_emit_set_long_const): Call can_be_built_by_li_and_rotldi.
gcc/testsuite/ChangeLog:
* gcc.target/powerpc/const-build.c: New test.
---
gcc/config/rs6000/rs6000.cc | 47 +--
.../gcc.target/powerpc/const-build.c | 57
+++
2 files changed, 98 insertions(+), 6 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/powerpc/const-build.c
diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 42f49e4a56b..acc332acc05 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -10258,6 +10258,31 @@ rs6000_emit_set_const (rtx dest, rtx source)
return true;
}
+/* Check if value C can be built by 2 instructions: one is 'li',
another is
+ rotldi.
Nit: different style, li is with "'" but rotldi isn't.
+
+ If so, *SHIFT is set to the shift operand of rotldi(rldicl), and
*MASK
+ is set to the mask operand of rotldi(rldicl), and return true.
+ Return false otherwise. */
+
+static bool
+can_be_built_by_li_and_rotldi (HOST_WIDE_INT c, int *shift,
+ HOST_WIDE_INT *mask)
+{
+ /* If C or ~C contains at least 49 successive zeros, then C can be
rotated
+ to/from a positive or negative value that 'li' is able to load.
*/
+ int n;
+ if (can_be_rotated_to_lowbits (c, 15, )
+ || can_be_rotated_to_lowbits (~c, 15, ))
+{
+ *mask = HOST_WIDE_INT_M1;
+ *shift = HOST_BITS_PER_WIDE_INT - n;
+ return true;
+}
+
+ return false;
+}
+
/* Subroutine of rs6000_emit_set_const, handling PowerPC64 DImode.
Output insns to set DEST equal to the constant C as a series of
lis, ori and shl instructions. */
@@ -10266,15 +10291,14 @@ static void
rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
{
rtx temp;
+ int shift;
+ HOST_WIDE_INT mask;
HOST_WIDE_INT ud1, ud2, ud3, ud4;
ud1 = c & 0x;
- c = c >> 16;
- ud2 = c & 0x;
- c = c >> 16;
- ud3 = c & 0x;
- c = c >> 16;
- ud4 = c & 0x;
+ ud2 = (c >> 16) & 0x;
+ ud3 = (c >> 32) & 0x;
+ ud4 = (c >> 48) & 0x;
if ((ud4 == 0x && ud3 == 0x && ud2 == 0x && (ud1 &
0x8000))
|| (ud4 == 0 && ud3 == 0 && ud2 == 0 && ! (ud1 & 0x8000)))
@@ -10305,6 +10329,17 @@ rs6000_emit_set_long_const (rtx dest,
HOST_WIDE_INT c)
emit_move_insn (dest, gen_rtx_XOR (DImode, temp,
GEN_INT ((ud2 ^ 0x) << 16)));
}
+ else if (can_be_built_by_li_and_rotldi (c, , ))
+{
+ temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
+ unsigned HOST_WIDE_INT imm = (c | ~mask);
+ imm = (imm >> shift) | (imm << (HOST_BITS_PER_WIDE_INT -
shift));
+
+ emit_move_insn (temp, GEN_INT (imm));
+ if (shift != 0)
+ temp = gen_rtx_ROTATE (DImode, temp, GEN_INT (shift));
+ emit_move_insn (dest, temp);
+}
else if (ud3 == 0 && ud4 == 0)
{
temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
diff --git a/gcc/testsuite/gcc.target/powerpc/const-build.c
b/gcc/testsuite/gcc.target/powerpc/const-build.c
new file mode 100644
index 000..69b37e2bb53
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/const-build.c
@@ -0,0 +1,57 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -save-temps" } */
+/* { dg-require-effective-target has_arch_ppc64 } */
+
+/* Verify that two instructions are sucessfully used to build
constants.
s/sucessfully/successfully/
+ One insn is li or lis, another is rotate: rldicl, rldicr or rldic.
*/
Nit: This patch is for insn li + insn rldicl only, you probably want to
keep
consistent in the comments.
The others look good to me, thanks!
Segher had one question on "~c" before, I saw you had explained for it,
it
makes sense to me, but in case he has more questions I'd defer the
final
approval to him.
BR,
Kewen
Re: [PATCH V4 1/4] rs6000: build constant via li;rotldi
Hi Jeff,
on 2023/7/4 10:18, Jiufu Guo via Gcc-patches wrote:
> Hi,
>
> If a constant is possible to be rotated to/from a positive or negative
> value from "li", then "li;rotldi" can be used to build the constant.
>
> Compare with the previous version:
> https://gcc.gnu.org/pipermail/gcc-patches/2023-June/621961.html
> This patch just did minor changes to the style and comments.
>
> Bootstrap and regtest pass on ppc64{,le}.
>
> Since the previous version is approved with conditions, this version
> explained the concern too. If no objection, I would like to apply
> this patch to trunk.
>
>
> BR,
> Jeff (Jiufu)
>
> gcc/ChangeLog:
>
> * config/rs6000/rs6000.cc (can_be_built_by_li_and_rotldi): New function.
> (rs6000_emit_set_long_const): Call can_be_built_by_li_and_rotldi.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.target/powerpc/const-build.c: New test.
> ---
> gcc/config/rs6000/rs6000.cc | 47 +--
> .../gcc.target/powerpc/const-build.c | 57 +++
> 2 files changed, 98 insertions(+), 6 deletions(-)
> create mode 100644 gcc/testsuite/gcc.target/powerpc/const-build.c
>
> diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
> index 42f49e4a56b..acc332acc05 100644
> --- a/gcc/config/rs6000/rs6000.cc
> +++ b/gcc/config/rs6000/rs6000.cc
> @@ -10258,6 +10258,31 @@ rs6000_emit_set_const (rtx dest, rtx source)
>return true;
> }
>
> +/* Check if value C can be built by 2 instructions: one is 'li', another is
> + rotldi.
Nit: different style, li is with "'" but rotldi isn't.
> +
> + If so, *SHIFT is set to the shift operand of rotldi(rldicl), and *MASK
> + is set to the mask operand of rotldi(rldicl), and return true.
> + Return false otherwise. */
> +
> +static bool
> +can_be_built_by_li_and_rotldi (HOST_WIDE_INT c, int *shift,
> +HOST_WIDE_INT *mask)
> +{
> + /* If C or ~C contains at least 49 successive zeros, then C can be rotated
> + to/from a positive or negative value that 'li' is able to load. */
> + int n;
> + if (can_be_rotated_to_lowbits (c, 15, )
> + || can_be_rotated_to_lowbits (~c, 15, ))
> +{
> + *mask = HOST_WIDE_INT_M1;
> + *shift = HOST_BITS_PER_WIDE_INT - n;
> + return true;
> +}
> +
> + return false;
> +}
> +
> /* Subroutine of rs6000_emit_set_const, handling PowerPC64 DImode.
> Output insns to set DEST equal to the constant C as a series of
> lis, ori and shl instructions. */
> @@ -10266,15 +10291,14 @@ static void
> rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
> {
>rtx temp;
> + int shift;
> + HOST_WIDE_INT mask;
>HOST_WIDE_INT ud1, ud2, ud3, ud4;
>
>ud1 = c & 0x;
> - c = c >> 16;
> - ud2 = c & 0x;
> - c = c >> 16;
> - ud3 = c & 0x;
> - c = c >> 16;
> - ud4 = c & 0x;
> + ud2 = (c >> 16) & 0x;
> + ud3 = (c >> 32) & 0x;
> + ud4 = (c >> 48) & 0x;
>
>if ((ud4 == 0x && ud3 == 0x && ud2 == 0x && (ud1 & 0x8000))
>|| (ud4 == 0 && ud3 == 0 && ud2 == 0 && ! (ud1 & 0x8000)))
> @@ -10305,6 +10329,17 @@ rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT
> c)
>emit_move_insn (dest, gen_rtx_XOR (DImode, temp,
>GEN_INT ((ud2 ^ 0x) << 16)));
> }
> + else if (can_be_built_by_li_and_rotldi (c, , ))
> +{
> + temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
> + unsigned HOST_WIDE_INT imm = (c | ~mask);
> + imm = (imm >> shift) | (imm << (HOST_BITS_PER_WIDE_INT - shift));
> +
> + emit_move_insn (temp, GEN_INT (imm));
> + if (shift != 0)
> + temp = gen_rtx_ROTATE (DImode, temp, GEN_INT (shift));
> + emit_move_insn (dest, temp);
> +}
>else if (ud3 == 0 && ud4 == 0)
> {
>temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
> diff --git a/gcc/testsuite/gcc.target/powerpc/const-build.c
> b/gcc/testsuite/gcc.target/powerpc/const-build.c
> new file mode 100644
> index 000..69b37e2bb53
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/const-build.c
> @@ -0,0 +1,57 @@
> +/* { dg-do run } */
> +/* { dg-options "-O2 -save-temps" } */
> +/* { dg-require-effective-target has_arch_ppc64 } */
> +
> +/* Verify that two instructions are sucessfully used to build constants.
s/sucessfully/successfully/
> + One insn is li or lis, another is rotate: rldicl, rldicr or rldic. */
Nit: This patch is for insn li + insn rldicl only, you probably want to keep
consistent in the comments.
The others look good to me, thanks!
Segher had one question on "~c" before, I saw you had explained for it, it
makes sense to me, but in case he has more questions I'd defer the final
approval to him.
BR,
Kewen
[PATCH V4 1/4] rs6000: build constant via li;rotldi
Hi,
If a constant is possible to be rotated to/from a positive or negative
value from "li", then "li;rotldi" can be used to build the constant.
Compare with the previous version:
https://gcc.gnu.org/pipermail/gcc-patches/2023-June/621961.html
This patch just did minor changes to the style and comments.
Bootstrap and regtest pass on ppc64{,le}.
Since the previous version is approved with conditions, this version
explained the concern too. If no objection, I would like to apply
this patch to trunk.
BR,
Jeff (Jiufu)
gcc/ChangeLog:
* config/rs6000/rs6000.cc (can_be_built_by_li_and_rotldi): New function.
(rs6000_emit_set_long_const): Call can_be_built_by_li_and_rotldi.
gcc/testsuite/ChangeLog:
* gcc.target/powerpc/const-build.c: New test.
---
gcc/config/rs6000/rs6000.cc | 47 +--
.../gcc.target/powerpc/const-build.c | 57 +++
2 files changed, 98 insertions(+), 6 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/powerpc/const-build.c
diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 42f49e4a56b..acc332acc05 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -10258,6 +10258,31 @@ rs6000_emit_set_const (rtx dest, rtx source)
return true;
}
+/* Check if value C can be built by 2 instructions: one is 'li', another is
+ rotldi.
+
+ If so, *SHIFT is set to the shift operand of rotldi(rldicl), and *MASK
+ is set to the mask operand of rotldi(rldicl), and return true.
+ Return false otherwise. */
+
+static bool
+can_be_built_by_li_and_rotldi (HOST_WIDE_INT c, int *shift,
+ HOST_WIDE_INT *mask)
+{
+ /* If C or ~C contains at least 49 successive zeros, then C can be rotated
+ to/from a positive or negative value that 'li' is able to load. */
+ int n;
+ if (can_be_rotated_to_lowbits (c, 15, )
+ || can_be_rotated_to_lowbits (~c, 15, ))
+{
+ *mask = HOST_WIDE_INT_M1;
+ *shift = HOST_BITS_PER_WIDE_INT - n;
+ return true;
+}
+
+ return false;
+}
+
/* Subroutine of rs6000_emit_set_const, handling PowerPC64 DImode.
Output insns to set DEST equal to the constant C as a series of
lis, ori and shl instructions. */
@@ -10266,15 +10291,14 @@ static void
rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
{
rtx temp;
+ int shift;
+ HOST_WIDE_INT mask;
HOST_WIDE_INT ud1, ud2, ud3, ud4;
ud1 = c & 0x;
- c = c >> 16;
- ud2 = c & 0x;
- c = c >> 16;
- ud3 = c & 0x;
- c = c >> 16;
- ud4 = c & 0x;
+ ud2 = (c >> 16) & 0x;
+ ud3 = (c >> 32) & 0x;
+ ud4 = (c >> 48) & 0x;
if ((ud4 == 0x && ud3 == 0x && ud2 == 0x && (ud1 & 0x8000))
|| (ud4 == 0 && ud3 == 0 && ud2 == 0 && ! (ud1 & 0x8000)))
@@ -10305,6 +10329,17 @@ rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
emit_move_insn (dest, gen_rtx_XOR (DImode, temp,
GEN_INT ((ud2 ^ 0x) << 16)));
}
+ else if (can_be_built_by_li_and_rotldi (c, , ))
+{
+ temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
+ unsigned HOST_WIDE_INT imm = (c | ~mask);
+ imm = (imm >> shift) | (imm << (HOST_BITS_PER_WIDE_INT - shift));
+
+ emit_move_insn (temp, GEN_INT (imm));
+ if (shift != 0)
+ temp = gen_rtx_ROTATE (DImode, temp, GEN_INT (shift));
+ emit_move_insn (dest, temp);
+}
else if (ud3 == 0 && ud4 == 0)
{
temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
diff --git a/gcc/testsuite/gcc.target/powerpc/const-build.c
b/gcc/testsuite/gcc.target/powerpc/const-build.c
new file mode 100644
index 000..69b37e2bb53
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/const-build.c
@@ -0,0 +1,57 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -save-temps" } */
+/* { dg-require-effective-target has_arch_ppc64 } */
+
+/* Verify that two instructions are sucessfully used to build constants.
+ One insn is li or lis, another is rotate: rldicl, rldicr or rldic. */
+
+#define NOIPA __attribute__ ((noipa))
+
+struct fun
+{
+ long long (*f) (void);
+ long long val;
+};
+
+long long NOIPA
+li_rotldi_1 (void)
+{
+ return 0x75310LL;
+}
+
+long long NOIPA
+li_rotldi_2 (void)
+{
+ return 0x2164LL;
+}
+
+long long NOIPA
+li_rotldi_3 (void)
+{
+ return 0x8531LL;
+}
+
+long long NOIPA
+li_rotldi_4 (void)
+{
+ return 0x2194LL;
+}
+
+struct fun arr[] = {
+ {li_rotldi_1, 0x75310LL},
+ {li_rotldi_2, 0x2164LL},
+ {li_rotldi_3, 0x8531LL},
+ {li_rotldi_4, 0x2194LL},
+};
+
+/* { dg-final { scan-assembler-times {\mrotldi\M} 4 } } */
+
+int
+main ()
+{
+ for (int i = 0; i < sizeof (arr) / sizeof (arr[0]); i++)
+if ((*arr[i].f) () != arr[i].val)
+ __builtin_abort ();
+
+ return 0;
+}
--
2.39.3
