diff mbox series

[11,1/5] x86: Remove "%!" before ret

Message ID	20220131185528.619688-2-hjl.tools@gmail.com
State	New
Headers	DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 79E50385C019 To: gcc-patches@gcc.gnu.org Subject: [GCC 11 PATCH 1/5] x86: Remove "%!" before ret Date: Mon, 31 Jan 2022 10:55:24 -0800 Message-Id: <20220131185528.619688-2-hjl.tools@gmail.com> In-Reply-To: <20220131185528.619688-1-hjl.tools@gmail.com> References: <20220131185528.619688-1-hjl.tools@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: list From: "H.J. Lu via Gcc-patches" <gcc-patches@gcc.gnu.org> Reply-To: "H.J. Lu" <hjl.tools@gmail.com> Errors-To: gcc-patches-bounces+patchwork=sourceware.org@gcc.gnu.org Sender: "Gcc-patches" <gcc-patches-bounces+patchwork=sourceware.org@gcc.gnu.org>
Series	x86: Backport straight-line-speculation mitigation \| [11,0/5] x86: Backport straight-line-speculation mitigation [11,1/5] x86: Remove "%!" before ret [11,2/5] x86: Add -mharden-sls=[none\|all\|return\|indirect-branch] [11,3/5] x86: Add -mindirect-branch-cs-prefix [11,4/5] x86: Rename -harden-sls=indirect-branch to -harden-sls=indirect-jmp [11,5/5] x86: Generate INT3 for __builtin_eh_return

Commit Message

H.J. Lu Jan. 31, 2022, 6:55 p.m. UTC

  Before MPX was removed, "%!" was mapped to

        case '!':
          if (ix86_bnd_prefixed_insn_p (current_output_insn))
            fputs ("bnd ", file);
          return;

After CET was added and MPX was removed, "%!" was mapped to

       case '!':
          if (ix86_notrack_prefixed_insn_p (current_output_insn))
            fputs ("notrack ", file);
          return;

ix86_notrack_prefixed_insn_p always returns false on ret since the
notrack prefix is only for indirect branches.  Remove the unused "%!"
before ret.

	PR target/103307
	* config/i386/i386.c (ix86_code_end): Remove "%!" before ret.
	(ix86_output_function_return): Likewise.
	* config/i386/i386.md (simple_return_pop_internal): Likewise.

(cherry picked from commit 8e410de43ce039bbe08f1e0195e3b6ec24f68cae)
---
 gcc/config/i386/i386.c  | 4 ++--
 gcc/config/i386/i386.md | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

Comments

Hongtao Liu Feb. 16, 2022, 6:46 a.m. UTC | #1

On Tue, Feb 1, 2022 at 2:56 AM H.J. Lu via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> Before MPX was removed, "%!" was mapped to
>
>         case '!':
>           if (ix86_bnd_prefixed_insn_p (current_output_insn))
>             fputs ("bnd ", file);
>           return;
>
> After CET was added and MPX was removed, "%!" was mapped to
>
>        case '!':
>           if (ix86_notrack_prefixed_insn_p (current_output_insn))
>             fputs ("notrack ", file);
>           return;
>
> ix86_notrack_prefixed_insn_p always returns false on ret since the
> notrack prefix is only for indirect branches.  Remove the unused "%!"
> before ret.
The patch LGTM.
BTW This patch seems to be independent of straight-line-speculation mitigation.
>
>         PR target/103307
>         * config/i386/i386.c (ix86_code_end): Remove "%!" before ret.
>         (ix86_output_function_return): Likewise.
>         * config/i386/i386.md (simple_return_pop_internal): Likewise.
>
> (cherry picked from commit 8e410de43ce039bbe08f1e0195e3b6ec24f68cae)
> ---
>  gcc/config/i386/i386.c  | 4 ++--
>  gcc/config/i386/i386.md | 2 +-
>  2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
> index 8e8c8beb366..4ba1a218ee6 100644
> --- a/gcc/config/i386/i386.c
> +++ b/gcc/config/i386/i386.c
> @@ -6000,7 +6000,7 @@ ix86_code_end (void)
>        xops[0] = gen_rtx_REG (Pmode, regno);
>        xops[1] = gen_rtx_MEM (Pmode, stack_pointer_rtx);
>        output_asm_insn ("mov%z0\t{%1, %0|%0, %1}", xops);
> -      output_asm_insn ("%!ret", NULL);
> +      fputs ("\tret\n", asm_out_file);
>        final_end_function ();
>        init_insn_lengths ();
>        free_after_compilation (cfun);
> @@ -16027,7 +16027,7 @@ ix86_output_function_return (bool long_p)
>      }
>
>    if (!long_p)
> -    return "%!ret";
> +    return "ret";
>
>    return "rep%; ret";
>  }
> diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
> index db9dbf384ad..1aff2ac2a82 100644
> --- a/gcc/config/i386/i386.md
> +++ b/gcc/config/i386/i386.md
> @@ -13912,7 +13912,7 @@ (define_insn_and_split "simple_return_pop_internal"
>    [(simple_return)
>     (use (match_operand:SI 0 "const_int_operand"))]
>    "reload_completed"
> -  "%!ret\t%0"
> +  "ret\t%0"
>    "&& cfun->machine->function_return_type != indirect_branch_keep"
>    [(const_int 0)]
>    "ix86_split_simple_return_pop_internal (operands[0]); DONE;"
> --
> 2.34.1
>

diff mbox series

Patch

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 8e8c8beb366..4ba1a218ee6 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -6000,7 +6000,7 @@  ix86_code_end (void)
       xops[0] = gen_rtx_REG (Pmode, regno);
       xops[1] = gen_rtx_MEM (Pmode, stack_pointer_rtx);
       output_asm_insn ("mov%z0\t{%1, %0|%0, %1}", xops);
-      output_asm_insn ("%!ret", NULL);
+      fputs ("\tret\n", asm_out_file);
       final_end_function ();
       init_insn_lengths ();
       free_after_compilation (cfun);
@@ -16027,7 +16027,7 @@  ix86_output_function_return (bool long_p)
     }
 
   if (!long_p)
-    return "%!ret";
+    return "ret";
 
   return "rep%; ret";
 }
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index db9dbf384ad..1aff2ac2a82 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -13912,7 +13912,7 @@  (define_insn_and_split "simple_return_pop_internal"
   [(simple_return)
    (use (match_operand:SI 0 "const_int_operand"))]
   "reload_completed"
-  "%!ret\t%0"
+  "ret\t%0"
   "&& cfun->machine->function_return_type != indirect_branch_keep"
   [(const_int 0)]
   "ix86_split_simple_return_pop_internal (operands[0]); DONE;"