From: Vladimir Makarov <vmakarov@redhat.com>
To: "gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>
Subject: [pushed] [PR103541] RA: Implement reuse of equivalent memory for caller saves optimization
Date: Tue, 7 Feb 2023 09:07:56 -0500 [thread overview]
Message-ID: <7ee31afa-d5c5-3d34-85e6-6034165876de@redhat.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 166 bytes --]
The following patch solves
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103541
The patch was successfully bootstrapped and tested on x86-64, aarch64,
and ppc64le.
[-- Attachment #2: pr103541.patch --]
[-- Type: text/x-patch, Size: 5559 bytes --]
commit f661c0bb6371f355966a67b5ce71398e80792948
Author: Vladimir N. Makarov <vmakarov@redhat.com>
Date: Tue Feb 7 08:27:36 2023 -0500
RA: Implement reuse of equivalent memory for caller saves optimization
The test case shows opportunity to reuse memory with constant address for
caller saves optimization for constant or pure function call. The patch
implements the memory reuse.
PR rtl-optimization/103541
gcc/ChangeLog:
* ira.h (struct ira_reg_equiv_s): Add new field caller_save_p.
* ira.cc (validate_equiv_mem): Check memref address variance.
(update_equiv_regs): Define caller save equivalence for
valid_combine.
(setup_reg_equiv): Clear defined_p flag for caller save equivalence.
* lra-constraints.cc (lra_copy_reg_equiv): Add new arg
call_save_p. Use caller save equivalence depending on the arg.
(split_reg): Adjust the call.
gcc/testsuite/ChangeLog:
* gcc.target/i386/pr103541.c: New.
diff --git a/gcc/ira.cc b/gcc/ira.cc
index 66df03e8a59..c6ee46286bc 100644
--- a/gcc/ira.cc
+++ b/gcc/ira.cc
@@ -3070,6 +3070,8 @@ validate_equiv_mem_from_store (rtx dest, const_rtx set ATTRIBUTE_UNUSED,
info->equiv_mem_modified = true;
}
+static int equiv_init_varies_p (rtx x);
+
enum valid_equiv { valid_none, valid_combine, valid_reload };
/* Verify that no store between START and the death of REG invalidates
@@ -3113,7 +3115,8 @@ validate_equiv_mem (rtx_insn *start, rtx reg, rtx memref)
been changed and all hell breaks loose. */
ret = valid_combine;
if (!MEM_READONLY_P (memref)
- && !RTL_CONST_OR_PURE_CALL_P (insn))
+ && (!RTL_CONST_OR_PURE_CALL_P (insn)
+ || equiv_init_varies_p (XEXP (memref, 0))))
return valid_none;
}
@@ -3766,7 +3769,18 @@ update_equiv_regs (void)
{
replacement = copy_rtx (SET_SRC (set));
if (validity == valid_reload)
- note = set_unique_reg_note (insn, REG_EQUIV, replacement);
+ {
+ note = set_unique_reg_note (insn, REG_EQUIV, replacement);
+ }
+ else
+ {
+ /* We still can use this equivalence for caller save
+ optimization in LRA. Mark this. */
+ ira_reg_equiv[regno].caller_save_p = true;
+ ira_reg_equiv[regno].init_insns
+ = gen_rtx_INSN_LIST (VOIDmode, insn,
+ ira_reg_equiv[regno].init_insns);
+ }
}
}
@@ -4156,7 +4170,7 @@ setup_reg_equiv (void)
legitimate, we ignore such REG_EQUIV notes. */
if (memory_operand (x, VOIDmode))
{
- ira_reg_equiv[i].defined_p = true;
+ ira_reg_equiv[i].defined_p = !ira_reg_equiv[i].caller_save_p;
ira_reg_equiv[i].memory = x;
continue;
}
diff --git a/gcc/ira.h b/gcc/ira.h
index 58b50dbe8a2..3d35025a46e 100644
--- a/gcc/ira.h
+++ b/gcc/ira.h
@@ -175,8 +175,11 @@ extern struct target_ira *this_target_ira;
/* Major structure describing equivalence info for a pseudo. */
struct ira_reg_equiv_s
{
- /* True if we can use this equivalence. */
+ /* True if we can use this as a general equivalence. */
bool defined_p;
+ /* True if we can use this equivalence only for caller save/restore
+ location. */
+ bool caller_save_p;
/* True if the usage of the equivalence is profitable. */
bool profitable_p;
/* Equiv. memory, constant, invariant, and initializing insns of
diff --git a/gcc/lra-constraints.cc b/gcc/lra-constraints.cc
index 7bffbc07ee2..dd4f68bbfc0 100644
--- a/gcc/lra-constraints.cc
+++ b/gcc/lra-constraints.cc
@@ -5771,14 +5771,17 @@ choose_split_class (enum reg_class allocno_class,
return best_cl;
}
-/* Copy any equivalence information from ORIGINAL_REGNO to NEW_REGNO.
- It only makes sense to call this function if NEW_REGNO is always
- equal to ORIGINAL_REGNO. */
+/* Copy any equivalence information from ORIGINAL_REGNO to NEW_REGNO. It only
+ makes sense to call this function if NEW_REGNO is always equal to
+ ORIGINAL_REGNO. Set up defined_p flag when caller_save_p flag is set up and
+ CALL_SAVE_P is true. */
static void
-lra_copy_reg_equiv (unsigned int new_regno, unsigned int original_regno)
+lra_copy_reg_equiv (unsigned int new_regno, unsigned int original_regno,
+ bool call_save_p)
{
- if (!ira_reg_equiv[original_regno].defined_p)
+ if (!ira_reg_equiv[original_regno].defined_p
+ && !(call_save_p && ira_reg_equiv[original_regno].caller_save_p))
return;
ira_expand_reg_equiv ();
@@ -5958,7 +5961,7 @@ split_reg (bool before_p, int original_regno, rtx_insn *insn,
rematerializing the original value instead of spilling to the stack. */
if (!HARD_REGISTER_NUM_P (original_regno)
&& mode == PSEUDO_REGNO_MODE (original_regno))
- lra_copy_reg_equiv (new_regno, original_regno);
+ lra_copy_reg_equiv (new_regno, original_regno, call_save_p);
lra_reg_info[new_regno].restore_rtx = regno_reg_rtx[original_regno];
bitmap_set_bit (&lra_split_regs, new_regno);
if (to != NULL)
diff --git a/gcc/testsuite/gcc.target/i386/pr103541.c b/gcc/testsuite/gcc.target/i386/pr103541.c
new file mode 100644
index 00000000000..72b257d42ee
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr103541.c
@@ -0,0 +1,14 @@
+/* PR rtl-optimization/103541 */
+/* { dg-do compile { target x86_64-*-* } } */
+/* { dg-options "-O2" } */
+
+float a;
+__attribute__((const)) float foo (float);
+
+float
+test()
+{
+ return a + foo(a) + a;
+}
+
+/* { dg-final { scan-assembler-not "\\\(%rsp\\\)" } } */
next reply other threads:[~2023-02-07 14:08 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-07 14:07 Vladimir Makarov [this message]
2023-02-08 3:48 ` Andrew Pinski
2023-02-08 13:29 ` Vladimir Makarov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=7ee31afa-d5c5-3d34-85e6-6034165876de@redhat.com \
--to=vmakarov@redhat.com \
--cc=gcc-patches@gcc.gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
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).