* [Committed V4] internal-fn: Support undefined rtx for uninitialized SSA_NAME[PR110751]
@ 2023-09-20 14:58 Juzhe-Zhong
2023-09-20 15:11 ` Palmer Dabbelt
0 siblings, 1 reply; 2+ messages in thread
From: Juzhe-Zhong @ 2023-09-20 14:58 UTC (permalink / raw)
To: gcc-patches; +Cc: rdapp.gcc, Juzhe-Zhong
According to PR: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110751
As Richard and Richi suggested, we recognize uninitialized SSA_NAME and convert it
into SCRATCH rtx if the target predicate allows SCRATCH.
It can help to reduce redundant data move instructions of targets like RISC-V.
Bootstrap and Regression on x86 passed.
gcc/ChangeLog:
* internal-fn.cc (expand_fn_using_insn): Support undefined rtx value.
* optabs.cc (maybe_legitimize_operand): Ditto.
(can_reuse_operands_p): Ditto.
* optabs.h (enum expand_operand_type): Ditto.
(create_undefined_input_operand): Ditto.
---
gcc/internal-fn.cc | 4 ++++
gcc/optabs.cc | 13 ++++++++++++-
gcc/optabs.h | 13 ++++++++++++-
3 files changed, 28 insertions(+), 2 deletions(-)
diff --git a/gcc/internal-fn.cc b/gcc/internal-fn.cc
index 0fd34359247..61d5a9e4772 100644
--- a/gcc/internal-fn.cc
+++ b/gcc/internal-fn.cc
@@ -247,6 +247,10 @@ expand_fn_using_insn (gcall *stmt, insn_code icode, unsigned int noutputs,
create_convert_operand_from (&ops[opno], rhs_rtx,
TYPE_MODE (rhs_type),
TYPE_UNSIGNED (rhs_type));
+ else if (TREE_CODE (rhs) == SSA_NAME
+ && SSA_NAME_IS_DEFAULT_DEF (rhs)
+ && VAR_P (SSA_NAME_VAR (rhs)))
+ create_undefined_input_operand (&ops[opno], TYPE_MODE (rhs_type));
else
create_input_operand (&ops[opno], rhs_rtx, TYPE_MODE (rhs_type));
opno += 1;
diff --git a/gcc/optabs.cc b/gcc/optabs.cc
index 32ff379ffc3..8b96f23aec0 100644
--- a/gcc/optabs.cc
+++ b/gcc/optabs.cc
@@ -8102,6 +8102,16 @@ maybe_legitimize_operand (enum insn_code icode, unsigned int opno,
goto input;
}
break;
+
+ case EXPAND_UNDEFINED_INPUT:
+ /* See if the predicate accepts a SCRATCH rtx, which in this context
+ indicates an undefined value. Use an uninitialized register if not. */
+ if (!insn_operand_matches (icode, opno, op->value))
+ {
+ op->value = gen_reg_rtx (op->mode);
+ goto input;
+ }
+ return true;
}
return insn_operand_matches (icode, opno, op->value);
}
@@ -8140,7 +8150,8 @@ can_reuse_operands_p (enum insn_code icode,
switch (op1->type)
{
case EXPAND_OUTPUT:
- /* Outputs must remain distinct. */
+ case EXPAND_UNDEFINED_INPUT:
+ /* Outputs and undefined intputs must remain distinct. */
return false;
case EXPAND_FIXED:
diff --git a/gcc/optabs.h b/gcc/optabs.h
index c80b7f4dc1b..9b78d40a46c 100644
--- a/gcc/optabs.h
+++ b/gcc/optabs.h
@@ -37,7 +37,8 @@ enum expand_operand_type {
EXPAND_CONVERT_TO,
EXPAND_CONVERT_FROM,
EXPAND_ADDRESS,
- EXPAND_INTEGER
+ EXPAND_INTEGER,
+ EXPAND_UNDEFINED_INPUT
};
/* Information about an operand for instruction expansion. */
@@ -117,6 +118,16 @@ create_input_operand (class expand_operand *op, rtx value,
create_expand_operand (op, EXPAND_INPUT, value, mode, false);
}
+/* Make OP describe an undefined input operand of mode MODE. MODE cannot
+ be null. */
+
+inline void
+create_undefined_input_operand (class expand_operand *op, machine_mode mode)
+{
+ create_expand_operand (op, EXPAND_UNDEFINED_INPUT, gen_rtx_SCRATCH (mode),
+ mode, false);
+}
+
/* Like create_input_operand, except that VALUE must first be converted
to mode MODE. UNSIGNED_P says whether VALUE is unsigned. */
--
2.36.3
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [Committed V4] internal-fn: Support undefined rtx for uninitialized SSA_NAME[PR110751]
2023-09-20 14:58 [Committed V4] internal-fn: Support undefined rtx for uninitialized SSA_NAME[PR110751] Juzhe-Zhong
@ 2023-09-20 15:11 ` Palmer Dabbelt
0 siblings, 0 replies; 2+ messages in thread
From: Palmer Dabbelt @ 2023-09-20 15:11 UTC (permalink / raw)
To: juzhe.zhong; +Cc: gcc-patches, rdapp.gcc, juzhe.zhong
On Wed, 20 Sep 2023 07:58:49 PDT (-0700), juzhe.zhong@rivai.ai wrote:
> According to PR: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110751
>
> As Richard and Richi suggested, we recognize uninitialized SSA_NAME and convert it
> into SCRATCH rtx if the target predicate allows SCRATCH.
>
> It can help to reduce redundant data move instructions of targets like RISC-V.
>
> Bootstrap and Regression on x86 passed.
>
> gcc/ChangeLog:
>
> * internal-fn.cc (expand_fn_using_insn): Support undefined rtx value.
> * optabs.cc (maybe_legitimize_operand): Ditto.
> (can_reuse_operands_p): Ditto.
> * optabs.h (enum expand_operand_type): Ditto.
> (create_undefined_input_operand): Ditto.
It's somewhat common to put the PR at the top of the ChangeLog (though I
pretty frequently forget as well).
>
> ---
> gcc/internal-fn.cc | 4 ++++
> gcc/optabs.cc | 13 ++++++++++++-
> gcc/optabs.h | 13 ++++++++++++-
> 3 files changed, 28 insertions(+), 2 deletions(-)
>
> diff --git a/gcc/internal-fn.cc b/gcc/internal-fn.cc
> index 0fd34359247..61d5a9e4772 100644
> --- a/gcc/internal-fn.cc
> +++ b/gcc/internal-fn.cc
> @@ -247,6 +247,10 @@ expand_fn_using_insn (gcall *stmt, insn_code icode, unsigned int noutputs,
> create_convert_operand_from (&ops[opno], rhs_rtx,
> TYPE_MODE (rhs_type),
> TYPE_UNSIGNED (rhs_type));
> + else if (TREE_CODE (rhs) == SSA_NAME
> + && SSA_NAME_IS_DEFAULT_DEF (rhs)
> + && VAR_P (SSA_NAME_VAR (rhs)))
> + create_undefined_input_operand (&ops[opno], TYPE_MODE (rhs_type));
> else
> create_input_operand (&ops[opno], rhs_rtx, TYPE_MODE (rhs_type));
> opno += 1;
> diff --git a/gcc/optabs.cc b/gcc/optabs.cc
> index 32ff379ffc3..8b96f23aec0 100644
> --- a/gcc/optabs.cc
> +++ b/gcc/optabs.cc
> @@ -8102,6 +8102,16 @@ maybe_legitimize_operand (enum insn_code icode, unsigned int opno,
> goto input;
> }
> break;
> +
> + case EXPAND_UNDEFINED_INPUT:
> + /* See if the predicate accepts a SCRATCH rtx, which in this context
> + indicates an undefined value. Use an uninitialized register if not. */
> + if (!insn_operand_matches (icode, opno, op->value))
> + {
> + op->value = gen_reg_rtx (op->mode);
> + goto input;
> + }
> + return true;
> }
> return insn_operand_matches (icode, opno, op->value);
> }
> @@ -8140,7 +8150,8 @@ can_reuse_operands_p (enum insn_code icode,
> switch (op1->type)
> {
> case EXPAND_OUTPUT:
> - /* Outputs must remain distinct. */
> + case EXPAND_UNDEFINED_INPUT:
> + /* Outputs and undefined intputs must remain distinct. */
> return false;
>
> case EXPAND_FIXED:
> diff --git a/gcc/optabs.h b/gcc/optabs.h
> index c80b7f4dc1b..9b78d40a46c 100644
> --- a/gcc/optabs.h
> +++ b/gcc/optabs.h
> @@ -37,7 +37,8 @@ enum expand_operand_type {
> EXPAND_CONVERT_TO,
> EXPAND_CONVERT_FROM,
> EXPAND_ADDRESS,
> - EXPAND_INTEGER
> + EXPAND_INTEGER,
> + EXPAND_UNDEFINED_INPUT
> };
>
> /* Information about an operand for instruction expansion. */
> @@ -117,6 +118,16 @@ create_input_operand (class expand_operand *op, rtx value,
> create_expand_operand (op, EXPAND_INPUT, value, mode, false);
> }
>
> +/* Make OP describe an undefined input operand of mode MODE. MODE cannot
> + be null. */
> +
> +inline void
> +create_undefined_input_operand (class expand_operand *op, machine_mode mode)
> +{
> + create_expand_operand (op, EXPAND_UNDEFINED_INPUT, gen_rtx_SCRATCH (mode),
> + mode, false);
> +}
> +
> /* Like create_input_operand, except that VALUE must first be converted
> to mode MODE. UNSIGNED_P says whether VALUE is unsigned. */
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2023-09-20 15:11 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-09-20 14:58 [Committed V4] internal-fn: Support undefined rtx for uninitialized SSA_NAME[PR110751] Juzhe-Zhong
2023-09-20 15:11 ` Palmer Dabbelt
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).