[PATCH][PR65802] Mark ifn_va_arg with ECF_NOTHROW

[PATCH][PR65802] Mark ifn_va_arg with ECF_NOTHROW

[Tom de Vries]

[-- Attachment #1: Type: text/plain, Size: 3537 bytes --]

Hi,

this patch fixes PR65802.

The problem described in PR65802 is that when compiling the test-case (included 
in the patch below) at -O0, the compiler runs into a gcc_assert ICE in 
redirect_eh_edge_1 during pass_cleanup_eh:
...
	  gcc_assert (lookup_stmt_eh_lp (throw_stmt) == old_lp_nr);
...


In more detail, during compilation the ifn_va_arg is marked at as a throwing 
function. That causes exception handling code to be generated, with exception 
handling edges:
...
;; basic block 2, loop depth 0, count 0, freq 0, maybe hot
;;  prev block 0, next block 3, flags: (NEW, REACHABLE)
;;  pred:       ENTRY (FALLTHRU)
[LP 1] # .MEM_5 = VDEF <.MEM_4(D)>
# USE = anything
# CLB = anything
_6 = VA_ARG (&cD.2333, 0B);
;;  succ:       7 (EH)
;;              3 (FALLTHRU)
...

After pass_lower_vaarg, the expansion of ifn_va_arg is spread over several basic 
blocks:
...
;;   basic block 2, loop depth 0, count 0, freq 0, maybe hot
;;    prev block 0, next block 11, flags: (NEW, REACHABLE)
;;    pred:       ENTRY (FALLTHRU)
;;    succ:       11 [100.0%]  (FALLTHRU)

;;   basic block 11, loop depth 0, count 0, freq 0, maybe hot
;;    prev block 2, next block 12, flags: (NEW)
;;    pred:       2 [100.0%]  (FALLTHRU)
   # VUSE <.MEM_4(D)>
   _22 = cD.2333.gp_offsetD.5;
   if (_22 >= 48)
     goto <bb 13> (<L6>);
   else
     goto <bb 12> (<L5>);
;;    succ:       13 (TRUE_VALUE)
;;                12 (FALSE_VALUE)

;;   basic block 12, loop depth 0, count 0, freq 0, maybe hot
;;    prev block 11, next block 13, flags: (NEW)
;;    pred:       11 (FALSE_VALUE)
<L5>:
   # VUSE <.MEM_4(D)>
   _23 = cD.2333.reg_save_areaD.8;
   # VUSE <.MEM_4(D)>
   _24 = cD.2333.gp_offsetD.5;
   _25 = (sizetype) _24;
   addr.1_26 = _23 + _25;
   # VUSE <.MEM_4(D)>
   _27 = cD.2333.gp_offsetD.5;
   _28 = _27 + 8;
   # .MEM_29 = VDEF <.MEM_4(D)>
   cD.2333.gp_offsetD.5 = _28;
   goto <bb 14> (<L7>);
;;    succ:       14 (FALLTHRU)

;;   basic block 13, loop depth 0, count 0, freq 0, maybe hot
;;    prev block 12, next block 14, flags: (NEW)
;;    pred:       11 (TRUE_VALUE)
<L6>:
   # VUSE <.MEM_4(D)>
   _30 = cD.2333.overflow_arg_areaD.7;
   addr.1_31 = _30;
   _32 = _30 + 8;
   # .MEM_33 = VDEF <.MEM_4(D)>
   cD.2333.overflow_arg_areaD.7 = _32;
;;    succ:       14 (FALLTHRU)

;;   basic block 14, loop depth 0, count 0, freq 0, maybe hot
;;    prev block 13, next block 15, flags: (NEW)
;;    pred:       12 (FALLTHRU)
;;                13 (FALLTHRU)
   # .MEM_20 = PHI <.MEM_29(12), .MEM_33(13)>
   # addr.1_21 = PHI <addr.1_26(12), addr.1_31(13)>
<L7>:
   # VUSE <.MEM_20>
   _6 = MEM[(intD.9 * * {ref-all})addr.1_21];
;;    succ:       15 (FALLTHRU)

;;   basic block 15, loop depth 0, count 0, freq 0, maybe hot
;;    prev block 14, next block 3, flags: (NEW)
;;    pred:       14 (FALLTHRU)
;;    succ:       7 (EH)
;;                3 (FALLTHRU)
...

And an ICE is triggered in redirect_eh_edge_1, because the code expects the last 
statement in a BB with an outgoing EH edge to be a throwing statement.

That's obviously not the case, since bb15 is empty. But also all the other 
statements in the expansion are non-throwing.


Looking at the representation before the ifn_va_arg, VA_ARG_EXPR is non-throwing 
(even with -fnon-call-exceptions).

And looking at the situation before the introduction of ifn_va_arg, the 
expansion of VA_ARG_EXPR also didn't contain any throwing statements.


This patch fixes the ICE by marking ifn_va_arg with ECF_NOTHROW.

Bootstrapped and reg-tested on x86_64.

OK for trunk?

Thanks,
- Tom

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Mark ifn_va_arg with ECF_NOTHROW

2015-04-20  Tom de Vries  <tom@codesourcery.com>

	PR tree-optimization/65802
	* internal-fn.def (VA_ARG): Add ECF_NOTROW to flags.

	* g++.dg/pr65802.C: New test.
---
 gcc/internal-fn.def            |  2 +-
 gcc/testsuite/g++.dg/pr65802.C | 29 +++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/pr65802.C

diff --git a/gcc/internal-fn.def b/gcc/internal-fn.def
index f557c64..7e19313 100644
--- a/gcc/internal-fn.def
+++ b/gcc/internal-fn.def
@@ -62,4 +62,4 @@ DEF_INTERNAL_FN (ADD_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
 DEF_INTERNAL_FN (SUB_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
 DEF_INTERNAL_FN (MUL_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
 DEF_INTERNAL_FN (TSAN_FUNC_EXIT, ECF_NOVOPS | ECF_LEAF | ECF_NOTHROW, NULL)
-DEF_INTERNAL_FN (VA_ARG, 0, NULL)
+DEF_INTERNAL_FN (VA_ARG, ECF_NOTHROW, NULL)
diff --git a/gcc/testsuite/g++.dg/pr65802.C b/gcc/testsuite/g++.dg/pr65802.C
new file mode 100644
index 0000000..26e5317
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr65802.C
@@ -0,0 +1,29 @@
+// { dg-do compile }
+// { dg-options "-O0" }
+
+typedef int tf ();
+
+struct S
+{
+  tf m_fn1;
+} a;
+
+void
+fn1 ()
+{
+  try
+    {
+      __builtin_va_list c;
+      {
+	int *d = __builtin_va_arg (c, int *);
+	int **e = &d;
+	__asm__("" : "=d"(e));
+	a.m_fn1 ();
+      }
+      a.m_fn1 ();
+    }
+  catch (...)
+    {
+
+    }
+}
-- 
1.9.1

Re: [PATCH][PR65802] Mark ifn_va_arg with ECF_NOTHROW

[Richard Biener]

On Tue, 21 Apr 2015, Tom de Vries wrote:

> Hi,
> 
> this patch fixes PR65802.
> 
> The problem described in PR65802 is that when compiling the test-case
> (included in the patch below) at -O0, the compiler runs into a gcc_assert ICE
> in redirect_eh_edge_1 during pass_cleanup_eh:
> ...
> 	  gcc_assert (lookup_stmt_eh_lp (throw_stmt) == old_lp_nr);
> ...
> 
> 
> In more detail, during compilation the ifn_va_arg is marked at as a throwing
> function. That causes exception handling code to be generated, with exception
> handling edges:
> ...
> ;; basic block 2, loop depth 0, count 0, freq 0, maybe hot
> ;;  prev block 0, next block 3, flags: (NEW, REACHABLE)
> ;;  pred:       ENTRY (FALLTHRU)
> [LP 1] # .MEM_5 = VDEF <.MEM_4(D)>
> # USE = anything
> # CLB = anything
> _6 = VA_ARG (&cD.2333, 0B);
> ;;  succ:       7 (EH)
> ;;              3 (FALLTHRU)
> ...
> 
> After pass_lower_vaarg, the expansion of ifn_va_arg is spread over several
> basic blocks:
> ...
> ;;   basic block 2, loop depth 0, count 0, freq 0, maybe hot
> ;;    prev block 0, next block 11, flags: (NEW, REACHABLE)
> ;;    pred:       ENTRY (FALLTHRU)
> ;;    succ:       11 [100.0%]  (FALLTHRU)
> 
> ;;   basic block 11, loop depth 0, count 0, freq 0, maybe hot
> ;;    prev block 2, next block 12, flags: (NEW)
> ;;    pred:       2 [100.0%]  (FALLTHRU)
>   # VUSE <.MEM_4(D)>
>   _22 = cD.2333.gp_offsetD.5;
>   if (_22 >= 48)
>     goto <bb 13> (<L6>);
>   else
>     goto <bb 12> (<L5>);
> ;;    succ:       13 (TRUE_VALUE)
> ;;                12 (FALSE_VALUE)
> 
> ;;   basic block 12, loop depth 0, count 0, freq 0, maybe hot
> ;;    prev block 11, next block 13, flags: (NEW)
> ;;    pred:       11 (FALSE_VALUE)
> <L5>:
>   # VUSE <.MEM_4(D)>
>   _23 = cD.2333.reg_save_areaD.8;
>   # VUSE <.MEM_4(D)>
>   _24 = cD.2333.gp_offsetD.5;
>   _25 = (sizetype) _24;
>   addr.1_26 = _23 + _25;
>   # VUSE <.MEM_4(D)>
>   _27 = cD.2333.gp_offsetD.5;
>   _28 = _27 + 8;
>   # .MEM_29 = VDEF <.MEM_4(D)>
>   cD.2333.gp_offsetD.5 = _28;
>   goto <bb 14> (<L7>);
> ;;    succ:       14 (FALLTHRU)
> 
> ;;   basic block 13, loop depth 0, count 0, freq 0, maybe hot
> ;;    prev block 12, next block 14, flags: (NEW)
> ;;    pred:       11 (TRUE_VALUE)
> <L6>:
>   # VUSE <.MEM_4(D)>
>   _30 = cD.2333.overflow_arg_areaD.7;
>   addr.1_31 = _30;
>   _32 = _30 + 8;
>   # .MEM_33 = VDEF <.MEM_4(D)>
>   cD.2333.overflow_arg_areaD.7 = _32;
> ;;    succ:       14 (FALLTHRU)
> 
> ;;   basic block 14, loop depth 0, count 0, freq 0, maybe hot
> ;;    prev block 13, next block 15, flags: (NEW)
> ;;    pred:       12 (FALLTHRU)
> ;;                13 (FALLTHRU)
>   # .MEM_20 = PHI <.MEM_29(12), .MEM_33(13)>
>   # addr.1_21 = PHI <addr.1_26(12), addr.1_31(13)>
> <L7>:
>   # VUSE <.MEM_20>
>   _6 = MEM[(intD.9 * * {ref-all})addr.1_21];
> ;;    succ:       15 (FALLTHRU)
> 
> ;;   basic block 15, loop depth 0, count 0, freq 0, maybe hot
> ;;    prev block 14, next block 3, flags: (NEW)
> ;;    pred:       14 (FALLTHRU)
> ;;    succ:       7 (EH)
> ;;                3 (FALLTHRU)
> ...
> 
> And an ICE is triggered in redirect_eh_edge_1, because the code expects the
> last statement in a BB with an outgoing EH edge to be a throwing statement.
> 
> That's obviously not the case, since bb15 is empty. But also all the other
> statements in the expansion are non-throwing.
> 
> 
> Looking at the representation before the ifn_va_arg, VA_ARG_EXPR is
> non-throwing (even with -fnon-call-exceptions).
> 
> And looking at the situation before the introduction of ifn_va_arg, the
> expansion of VA_ARG_EXPR also didn't contain any throwing statements.
> 
> 
> This patch fixes the ICE by marking ifn_va_arg with ECF_NOTHROW.
> 
> Bootstrapped and reg-tested on x86_64.
> 
> OK for trunk?

Ok.

Thanks,
Richard.

> Thanks,
> - Tom
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Jennifer Guild,
Dilip Upmanyu, Graham Norton HRB 21284 (AG Nuernberg)

Re: [PATCH][PR65802] Mark ifn_va_arg with ECF_NOTHROW

[Jan Hubicka]

> Mark ifn_va_arg with ECF_NOTHROW

You can defnitly make it ECF_LEAF too. I wonder if we can make it ECF_CONST or at leat PURE
this would help to keep variadic functions const/pure that may be moderately interesting
in practice.

Honza
> 
> 2015-04-20  Tom de Vries  <tom@codesourcery.com>
> 
> 	PR tree-optimization/65802
> 	* internal-fn.def (VA_ARG): Add ECF_NOTROW to flags.
> 
> 	* g++.dg/pr65802.C: New test.
> ---
>  gcc/internal-fn.def            |  2 +-
>  gcc/testsuite/g++.dg/pr65802.C | 29 +++++++++++++++++++++++++++++
>  2 files changed, 30 insertions(+), 1 deletion(-)
>  create mode 100644 gcc/testsuite/g++.dg/pr65802.C
> 
> diff --git a/gcc/internal-fn.def b/gcc/internal-fn.def
> index f557c64..7e19313 100644
> --- a/gcc/internal-fn.def
> +++ b/gcc/internal-fn.def
> @@ -62,4 +62,4 @@ DEF_INTERNAL_FN (ADD_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
>  DEF_INTERNAL_FN (SUB_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
>  DEF_INTERNAL_FN (MUL_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
>  DEF_INTERNAL_FN (TSAN_FUNC_EXIT, ECF_NOVOPS | ECF_LEAF | ECF_NOTHROW, NULL)
> -DEF_INTERNAL_FN (VA_ARG, 0, NULL)
> +DEF_INTERNAL_FN (VA_ARG, ECF_NOTHROW, NULL)
> diff --git a/gcc/testsuite/g++.dg/pr65802.C b/gcc/testsuite/g++.dg/pr65802.C
> new file mode 100644
> index 0000000..26e5317
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/pr65802.C
> @@ -0,0 +1,29 @@
> +// { dg-do compile }
> +// { dg-options "-O0" }
> +
> +typedef int tf ();
> +
> +struct S
> +{
> +  tf m_fn1;
> +} a;
> +
> +void
> +fn1 ()
> +{
> +  try
> +    {
> +      __builtin_va_list c;
> +      {
> +	int *d = __builtin_va_arg (c, int *);
> +	int **e = &d;
> +	__asm__("" : "=d"(e));
> +	a.m_fn1 ();
> +      }
> +      a.m_fn1 ();
> +    }
> +  catch (...)
> +    {
> +
> +    }
> +}
> -- 
> 1.9.1
> 

Re: [PATCH][PR65802] Mark ifn_va_arg with ECF_NOTHROW

[Richard Biener]

On Tue, 21 Apr 2015, Jan Hubicka wrote:

> > Mark ifn_va_arg with ECF_NOTHROW
> 
> You can defnitly make it ECF_LEAF too. I wonder if we can make it ECF_CONST or at leat PURE
> this would help to keep variadic functions const/pure that may be moderately interesting
> in practice.

Yes to ECF_LEAF but it isn't const or pure as it modifies the valist 
argument so you can't for example DCE va_arg (...) if the result isn't
needed.

Richard.

> Honza
> > 
> > 2015-04-20  Tom de Vries  <tom@codesourcery.com>
> > 
> > 	PR tree-optimization/65802
> > 	* internal-fn.def (VA_ARG): Add ECF_NOTROW to flags.
> > 
> > 	* g++.dg/pr65802.C: New test.
> > ---
> >  gcc/internal-fn.def            |  2 +-
> >  gcc/testsuite/g++.dg/pr65802.C | 29 +++++++++++++++++++++++++++++
> >  2 files changed, 30 insertions(+), 1 deletion(-)
> >  create mode 100644 gcc/testsuite/g++.dg/pr65802.C
> > 
> > diff --git a/gcc/internal-fn.def b/gcc/internal-fn.def
> > index f557c64..7e19313 100644
> > --- a/gcc/internal-fn.def
> > +++ b/gcc/internal-fn.def
> > @@ -62,4 +62,4 @@ DEF_INTERNAL_FN (ADD_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
> >  DEF_INTERNAL_FN (SUB_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
> >  DEF_INTERNAL_FN (MUL_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
> >  DEF_INTERNAL_FN (TSAN_FUNC_EXIT, ECF_NOVOPS | ECF_LEAF | ECF_NOTHROW, NULL)
> > -DEF_INTERNAL_FN (VA_ARG, 0, NULL)
> > +DEF_INTERNAL_FN (VA_ARG, ECF_NOTHROW, NULL)
> > diff --git a/gcc/testsuite/g++.dg/pr65802.C b/gcc/testsuite/g++.dg/pr65802.C
> > new file mode 100644
> > index 0000000..26e5317
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/pr65802.C
> > @@ -0,0 +1,29 @@
> > +// { dg-do compile }
> > +// { dg-options "-O0" }
> > +
> > +typedef int tf ();
> > +
> > +struct S
> > +{
> > +  tf m_fn1;
> > +} a;
> > +
> > +void
> > +fn1 ()
> > +{
> > +  try
> > +    {
> > +      __builtin_va_list c;
> > +      {
> > +	int *d = __builtin_va_arg (c, int *);
> > +	int **e = &d;
> > +	__asm__("" : "=d"(e));
> > +	a.m_fn1 ();
> > +      }
> > +      a.m_fn1 ();
> > +    }
> > +  catch (...)
> > +    {
> > +
> > +    }
> > +}
> > -- 
> > 1.9.1
> > 
> 
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Jennifer Guild,
Dilip Upmanyu, Graham Norton HRB 21284 (AG Nuernberg)

Re: [PATCH][PR65802] Mark ifn_va_arg with ECF_NOTHROW

[Bin.Cheng]

On Tue, Apr 21, 2015 at 3:10 PM, Tom de Vries <Tom_deVries@mentor.com> wrote:
> Hi,
>
> this patch fixes PR65802.
>
> diff --git a/gcc/testsuite/g++.dg/
pr65802.C b/gcc/testsuite/g++.dg/pr65802.C
> new file mode 100644
> index 0000000..26e5317
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/pr65802.C
> @@ -0,0 +1,29 @@
> +// { dg-do compile }
> +// { dg-options "-O0" }
> +
> +typedef int tf ();
> +
> +struct S
> +{
> +  tf m_fn1;
> +} a;
> +
> +void
> +fn1 ()
> +{
> +  try
> +    {
> +      __builtin_va_list c;
> +      {
> +     int *d = __builtin_va_arg (c, int *);
> +     int **e = &d;
> +     __asm__("" : "=d"(e));
Hi, thanks for fixing the issue.
But 'd' is a machine specific constraint?  This case failed on all arm
processors.

Thanks,
bin
> +     a.m_fn1 ();
> +      }
> +      a.m_fn1 ();
> +    }
> +  catch (...)
> +    {
> +
> +    }
> +}

> OK for trunk?
>
> Thanks,
> - Tom

Re: [PATCH][PR65802] Mark ifn_va_arg with ECF_NOTHROW

[Tom de Vries]

[-- Attachment #1: Type: text/plain, Size: 987 bytes --]

On 24-04-15 05:25, Bin.Cheng wrote:
> On Tue, Apr 21, 2015 at 3:10 PM, Tom de Vries <Tom_deVries@mentor.com> wrote:
>> Hi,
>>
>> this patch fixes PR65802.
>>
>> diff --git a/gcc/testsuite/g++.dg/
> pr65802.C b/gcc/testsuite/g++.dg/pr65802.C
>> new file mode 100644
>> index 0000000..26e5317
>> --- /dev/null
>> +++ b/gcc/testsuite/g++.dg/pr65802.C
>> @@ -0,0 +1,29 @@
>> +// { dg-do compile }
>> +// { dg-options "-O0" }
>> +
>> +typedef int tf ();
>> +
>> +struct S
>> +{
>> +  tf m_fn1;
>> +} a;
>> +
>> +void
>> +fn1 ()
>> +{
>> +  try
>> +    {
>> +      __builtin_va_list c;
>> +      {
>> +     int *d = __builtin_va_arg (c, int *);
>> +     int **e = &d;
>> +     __asm__("" : "=d"(e));
> Hi, thanks for fixing the issue.
> But 'd' is a machine specific constraint?  This case failed on all arm
> processors.

Hi,

I've rewritten the test-case for C, made the function a valid stdargs function, 
and removed the superfluous inline assembly.

Committed as attached.

Thanks,
- Tom

[-- Attachment #2: 0001-Replace-g-.dg-pr65802.C-with-gcc.dg-pr65802.c.patch --]
[-- Type: text/x-patch, Size: 1388 bytes --]

2015-04-24  Tom de Vries  <tom@codesourcery.com>

	PR tree-optimization/65802
	* g++.dg/pr65802.C: Move to ...
	* gcc.dg/pr65802.c: ... here.  Add -fexceptions to dg-options. Include
	stdarg.h.  Rewrite for C.
	(fn1): Use va_list and va_arg.  Make variable args function.  Add use of
	va_start and va_end.  Remove unnecessary inline asm.

diff --git a/gcc/testsuite/g++.dg/pr65802.C b/gcc/testsuite/g++.dg/pr65802.C
deleted file mode 100644
index 26e5317..0000000
--- a/gcc/testsuite/g++.dg/pr65802.C
+++ /dev/null
@@ -1,29 +0,0 @@
-// { dg-do compile }
-// { dg-options "-O0" }
-
-typedef int tf ();
-
-struct S
-{
-  tf m_fn1;
-} a;
-
-void
-fn1 ()
-{
-  try
-    {
-      __builtin_va_list c;
-      {
-	int *d = __builtin_va_arg (c, int *);
-	int **e = &d;
-	__asm__("" : "=d"(e));
-	a.m_fn1 ();
-      }
-      a.m_fn1 ();
-    }
-  catch (...)
-    {
-
-    }
-}
diff --git a/gcc/testsuite/gcc.dg/pr65802.c b/gcc/testsuite/gcc.dg/pr65802.c
new file mode 100644
index 0000000..fcec234
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr65802.c
@@ -0,0 +1,28 @@
+/* { dg-do compile } */
+/* { dg-options "-O0 -fexceptions" } */
+
+#include <stdarg.h>
+
+struct S
+{
+  int (*m_fn1) (void);
+} a;
+
+void
+fn1 (int d, ...)
+{
+  va_list c;
+  va_start (c, d);
+
+  {
+    int *d = va_arg (c, int *);
+
+    int **e = &d;
+
+    a.m_fn1 ();
+  }
+
+  a.m_fn1 ();
+
+  va_end (c);
+}
-- 
1.9.1

Re: [PATCH][PR65802] Mark ifn_va_arg with ECF_NOTHROW

[Tom de Vries]

[-- Attachment #1: Type: text/plain, Size: 606 bytes --]

On 21-04-15 09:50, Richard Biener wrote:
> On Tue, 21 Apr 2015, Jan Hubicka wrote:
>
>>> Mark ifn_va_arg with ECF_NOTHROW
>>
>> You can definitely make it ECF_LEAF too. I wonder if we can make it ECF_CONST or at leat PURE
>> this would help to keep variadic functions const/pure that may be moderately interesting
>> in practice.
>
> Yes to ECF_LEAF but it isn't const or pure as it modifies the valist
> argument so you can't for example DCE va_arg (...) if the result isn't
> needed.
>

I've committed this patch that marks ifn_va_arg as ECF_LEAF.

Bootstrapped and reg-tested on x86_64.

Thanks,
- Tom


[-- Attachment #2: 0001-Mark-ifn_va_arg-as-ECF_LEAF.patch --]
[-- Type: text/x-patch, Size: 720 bytes --]

Mark ifn_va_arg as ECF_LEAF

2015-04-26  Tom de Vries  <tom@codesourcery.com>

	PR tree-optimization/65826
	* internal-fn.def: Mark VA_ARG with ECF_LEAF.

diff --git a/gcc/internal-fn.def b/gcc/internal-fn.def
index 7e19313..ba5c2c1 100644
--- a/gcc/internal-fn.def
+++ b/gcc/internal-fn.def
@@ -62,4 +62,4 @@ DEF_INTERNAL_FN (ADD_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
 DEF_INTERNAL_FN (SUB_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
 DEF_INTERNAL_FN (MUL_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
 DEF_INTERNAL_FN (TSAN_FUNC_EXIT, ECF_NOVOPS | ECF_LEAF | ECF_NOTHROW, NULL)
-DEF_INTERNAL_FN (VA_ARG, ECF_NOTHROW, NULL)
+DEF_INTERNAL_FN (VA_ARG, ECF_NOTHROW | ECF_LEAF, NULL)
-- 
1.9.1