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Re: [PATCH] PR target/66819: Allow indirect sibcall with register arguments
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Uros Bizjak <ubizjak at gmail dot com>
- Cc: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Date: Fri, 10 Jul 2015 10:10:19 -0700
- Subject: Re: [PATCH] PR target/66819: Allow indirect sibcall with register arguments
- Authentication-results: sourceware.org; auth=none
- References: <20150709105439 dot GA19247 at gmail dot com> <CAFULd4Zg3-L23+UAQHsP3j7a0iPboFyxu+ETR3cFx7eh4r0aow at mail dot gmail dot com>
On Fri, Jul 10, 2015 at 9:30 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
> On Thu, Jul 9, 2015 at 12:54 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> Indirect sibcall with register arguments is OK when there is register
>> available for argument passing.
>>
>> OK for trunk if there is no regression?
>>
>>
>> H.J.
>> ---
>> gcc/
>>
>> PR target/66819
>> * config/i386/i386.c (ix86_function_ok_for_sibcall): Allow
>> indirect sibcall with register arguments if register available
>> for argument passing.
>> (init_cumulative_args): Set cfun->machine->arg_reg_available_p
>> to cum->nregs != 0.
>> (function_arg_advance_32): Set cfun->machine->arg_reg_available_p
>> to 0 when setting cum->nregs = 0.
>
> Do we also need similar functionality for 64bit ABIs? What happens if
> we are out of argument regs there?
64-bit is OK since we have rax, r10 and r11 as scratch registers which
aren't used to pass arguments.
>> * config/i386/i386.h (machine_function): Add arg_reg_available_p.
>>
>> gcc/testsuite/
>>
>> PR target/66819
>> * gcc.target/i386/pr66819-1.c: New test.
>> * gcc.target/i386/pr66819-2.c: Likewise.
>> * gcc.target/i386/pr66819-3.c: Likewise.
>> * gcc.target/i386/pr66819-4.c: Likewise.
>> * gcc.target/i386/pr66819-5.c: Likewise.
>> ---
>> gcc/config/i386/i386.c | 15 +++++++++------
>> gcc/config/i386/i386.h | 3 +++
>> gcc/testsuite/gcc.target/i386/pr66819-1.c | 8 ++++++++
>> gcc/testsuite/gcc.target/i386/pr66819-2.c | 8 ++++++++
>> gcc/testsuite/gcc.target/i386/pr66819-3.c | 10 ++++++++++
>> gcc/testsuite/gcc.target/i386/pr66819-4.c | 12 ++++++++++++
>> gcc/testsuite/gcc.target/i386/pr66819-5.c | 10 ++++++++++
>> 7 files changed, 60 insertions(+), 6 deletions(-)
>> create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-1.c
>> create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-2.c
>> create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-3.c
>> create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-4.c
>> create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-5.c
>>
>> diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
>> index 54ee6f3..85e59a8 100644
>> --- a/gcc/config/i386/i386.c
>> +++ b/gcc/config/i386/i386.c
>> @@ -5628,12 +5628,12 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
>> if (!decl
>> || (TARGET_DLLIMPORT_DECL_ATTRIBUTES && DECL_DLLIMPORT_P (decl)))
>> {
>> - if (ix86_function_regparm (type, NULL) >= 3)
>> - {
>> - /* ??? Need to count the actual number of registers to be used,
>> - not the possible number of registers. Fix later. */
>> - return false;
>> - }
>> + /* FIXME: The symbol indirect call doesn't need a
>> + call-clobbered register. But we don't know if
>> + this is a symbol indirect call or not here. */
>> + if (ix86_function_regparm (type, NULL) >= 3
>> + && !cfun->machine->arg_reg_available_p)
>
> Isn't enough to look at arg_reg_available here?
We need to check ix86_function_regparm since nregs is 0 if
-mregparm=N isn't used and pr65753.c will fail.
>> + return false;
>> }
>> }
>>
>> @@ -6567,6 +6567,7 @@ init_cumulative_args (CUMULATIVE_ARGS *cum, /* Argument info to initialize */
>> ? X86_64_REGPARM_MAX
>> : X86_64_MS_REGPARM_MAX);
>> }
>> + cfun->machine->arg_reg_available_p = cum->nregs != 0;
>
> false instead of 0. This is a boolean.
Updated.
>> if (TARGET_SSE)
>> {
>> cum->sse_nregs = SSE_REGPARM_MAX;
>> @@ -6636,6 +6637,7 @@ init_cumulative_args (CUMULATIVE_ARGS *cum, /* Argument info to initialize */
>> else
>> cum->nregs = ix86_function_regparm (fntype, fndecl);
>> }
>> + cfun->machine->arg_reg_available_p = cum->nregs != 0;
>
> IMO, cum->nregs > 0 would be more descriptive.
Updated.
>> /* Set up the number of SSE registers used for passing SFmode
>> and DFmode arguments. Warn for mismatching ABI. */
>> @@ -7584,6 +7586,7 @@ pass_in_reg:
>> {
>> cum->nregs = 0;
>> cum->regno = 0;
>> + cfun->machine->arg_reg_available_p = 0;
>> }
>> break;
>>
>> diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h
>> index 74334ff..0b6e304 100644
>> --- a/gcc/config/i386/i386.h
>> +++ b/gcc/config/i386/i386.h
>> @@ -2479,6 +2479,9 @@ struct GTY(()) machine_function {
>> /* If true, it is safe to not save/restore DRAP register. */
>> BOOL_BITFIELD no_drap_save_restore : 1;
>>
>> + /* If true, there is register available for argument passing. */
>> + BOOL_BITFIELD arg_reg_available_p : 1;
>
> This is not a predicate, but a boolean flag. Please remove _p from the name.
Updated.
Here is the updated patch. OK for trunk?
Thanks.
--
H.J.
From 3bcd6c122684d896840b2feb756e9b9ab8723ecc Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Wed, 8 Jul 2015 21:10:25 -0700
Subject: [PATCH] Allow indirect sibcall with register arguments
Indirect sibcall with register arguments is OK when there is register
available for argument passing.
gcc/
PR target/66819
* config/i386/i386.c (ix86_function_ok_for_sibcall): Allow
indirect sibcall with register arguments if register available
for argument passing.
(init_cumulative_args): Set cfun->machine->arg_reg_available
to cum->nregs != 0.
(function_arg_advance_32): Set cfun->machine->arg_reg_available
to 0 when setting cum->nregs = 0.
* config/i386/i386.h (machine_function): Add arg_reg_available.
gcc/testsuite/
PR target/66819
* gcc.target/i386/pr66819-1.c: New test.
* gcc.target/i386/pr66819-2.c: Likewise.
* gcc.target/i386/pr66819-3.c: Likewise.
* gcc.target/i386/pr66819-4.c: Likewise.
* gcc.target/i386/pr66819-5.c: Likewise.
---
gcc/config/i386/i386.c | 16 ++++++++++------
gcc/config/i386/i386.h | 3 +++
gcc/testsuite/gcc.target/i386/pr66819-1.c | 8 ++++++++
gcc/testsuite/gcc.target/i386/pr66819-2.c | 8 ++++++++
gcc/testsuite/gcc.target/i386/pr66819-3.c | 10 ++++++++++
gcc/testsuite/gcc.target/i386/pr66819-4.c | 12 ++++++++++++
gcc/testsuite/gcc.target/i386/pr66819-5.c | 10 ++++++++++
7 files changed, 61 insertions(+), 6 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-1.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-2.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-3.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-4.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-5.c
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 57b8acc..c0a1993 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -5629,12 +5629,12 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
if (!decl
|| (TARGET_DLLIMPORT_DECL_ATTRIBUTES && DECL_DLLIMPORT_P (decl)))
{
- if (ix86_function_regparm (type, NULL) >= 3)
- {
- /* ??? Need to count the actual number of registers to be used,
- not the possible number of registers. Fix later. */
- return false;
- }
+ /* ??? The symbol indirect call doesn't need a
+ call-clobbered register. But we don't know if
+ this is a symbol indirect call or not here. */
+ if (ix86_function_regparm (type, NULL) >= 3
+ && !cfun->machine->arg_reg_available)
+ return false;
}
}
@@ -6610,6 +6610,7 @@ init_cumulative_args (CUMULATIVE_ARGS *cum, /* Argument info to initialize */
if (stdarg_p (fntype))
{
cum->nregs = 0;
+ cfun->machine->arg_reg_available = false;
cum->sse_nregs = 0;
cum->mmx_nregs = 0;
cum->warn_avx512f = false;
@@ -6642,6 +6643,8 @@ init_cumulative_args (CUMULATIVE_ARGS *cum, /* Argument info to initialize */
and DFmode arguments. Warn for mismatching ABI. */
cum->float_in_sse = ix86_function_sseregparm (fntype, fndecl, true);
}
+
+ cfun->machine->arg_reg_available = (cum->nregs > 0);
}
/* Return the "natural" mode for TYPE. In most cases, this is just TYPE_MODE.
@@ -7584,6 +7587,7 @@ pass_in_reg:
if (cum->nregs <= 0)
{
cum->nregs = 0;
+ cfun->machine->arg_reg_available = false;
cum->regno = 0;
}
break;
diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h
index 74334ff..14006c8 100644
--- a/gcc/config/i386/i386.h
+++ b/gcc/config/i386/i386.h
@@ -2479,6 +2479,9 @@ struct GTY(()) machine_function {
/* If true, it is safe to not save/restore DRAP register. */
BOOL_BITFIELD no_drap_save_restore : 1;
+ /* If true, there is register available for argument passing. */
+ BOOL_BITFIELD arg_reg_available : 1;
+
/* During prologue/epilogue generation, the current frame state.
Otherwise, the frame state at the end of the prologue. */
struct machine_frame_state fs;
diff --git a/gcc/testsuite/gcc.target/i386/pr66819-1.c b/gcc/testsuite/gcc.target/i386/pr66819-1.c
new file mode 100644
index 0000000..7c8a1ab
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr66819-1.c
@@ -0,0 +1,8 @@
+/* { dg-do compile { target ia32 } } */
+/* { dg-options "-O2 -mregparm=3" } */
+/* { dg-final { scan-assembler-not "call" } } */
+
+void foo(void (*bar)(void))
+{
+ bar();
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr66819-2.c b/gcc/testsuite/gcc.target/i386/pr66819-2.c
new file mode 100644
index 0000000..9de4f97
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr66819-2.c
@@ -0,0 +1,8 @@
+/* { dg-do compile { target ia32 } } */
+/* { dg-options "-fPIC -O2 -mregparm=3" } */
+/* { dg-final { scan-assembler-not "call" } } */
+
+void foo(void (*bar)(void))
+{
+ bar();
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr66819-3.c b/gcc/testsuite/gcc.target/i386/pr66819-3.c
new file mode 100644
index 0000000..3bc5a34
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr66819-3.c
@@ -0,0 +1,10 @@
+/* { dg-do compile { target ia32 } } */
+/* { dg-options "-O2 -mregparm=3" } */
+/* { dg-final { scan-assembler-not "call" } } */
+
+void (*bar)(int, int);
+
+void foo(int i, int j)
+{
+ bar(i, j);
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr66819-4.c b/gcc/testsuite/gcc.target/i386/pr66819-4.c
new file mode 100644
index 0000000..18b2ccf
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr66819-4.c
@@ -0,0 +1,12 @@
+/* { dg-do compile { target ia32 } } */
+/* { dg-options "-O2 -mregparm=3" } */
+/* { dg-final { scan-assembler-not "call" } } */
+
+#include <stdarg.h>
+
+void (*bar)(int, va_list);
+
+void foo(int i, va_list args)
+{
+ bar(i, args);
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr66819-5.c b/gcc/testsuite/gcc.target/i386/pr66819-5.c
new file mode 100644
index 0000000..6b019d1
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr66819-5.c
@@ -0,0 +1,10 @@
+/* { dg-do compile { target ia32 } } */
+/* { dg-options "-O2 -mregparm=3" } */
+/* { dg-final { scan-assembler "call" } } */
+
+void (*bar)(int, int, int);
+
+void foo(int i, int j, int k)
+{
+ bar(i, j, k);
+}
--
2.4.3