Re: [PING^2] [PATCH][5a/5] Postpone expanding va_arg until pass_stdarg

[Tom de Vries <Tom_deVries@mentor.com>]

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On 09/06/15 13:03, Richard Biener wrote:
> On Tue, 9 Jun 2015, Alan Lawrence wrote:
>
>> Hmmm. One side effect of this is that the line number information available in
>> the target hook gimplify_va_arg_expr, is now just the name of the containing
>> function, rather than the specific use of va_arg. Is there some way to get
>> this more precise location (e.g. gimple_location(stmt) in expand_ifn_va_arg_1,
>> the only caller of said hook)? I don't really want to have to add an extra
>> parameter to the target hook...
>
> The x86 variant doesn't use any locations but if then the caller of
> the target hook (expand_ifn_va_arg_1) should assign the IFNs location
> to all statements expanded from it (it could set input_location to
> that during the target hook call...)
>

That seems to work.

The scan-assembler-not test in the testcase in attached patch:
- fails without the expand_ifn_va_arg_1 patch hunk, and
- passes with that hunk.

I'll put it through bootstrap and reg-test on x86_64.

OK for trunk if that goes well?

Thanks,
- Tom

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Handle location in expand_ifn_va_arg_1

2015-06-09  Tom de Vries  <tom@codesourcery.com>

	* tree-stdarg.c (expand_ifn_va_arg_1): Handle location.

	* gcc.target/i386/vararg-loc.c: New test.
---
 gcc/testsuite/gcc.target/i386/vararg-loc.c | 27 +++++++++++++++++++++++++++
 gcc/tree-stdarg.c                          |  4 ++++
 2 files changed, 31 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/i386/vararg-loc.c

diff --git a/gcc/testsuite/gcc.target/i386/vararg-loc.c b/gcc/testsuite/gcc.target/i386/vararg-loc.c
new file mode 100644
index 0000000..f236fe3
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/vararg-loc.c
@@ -0,0 +1,27 @@
+/* { dg-do compile } */
+/* { dg-options "-g -O0" } */
+
+#include <stdarg.h>
+
+int				/* 6.  */
+				/* 7.  */
+f (int a, ...)			/* 8.  */
+				/* 9.  */
+{
+
+  int sum = a;
+
+  va_list ap;
+
+  va_start (ap, a);
+
+  sum += va_arg (ap, int);	/* 18.  */
+
+  sum += va_arg (ap, int);	/* 20.  */
+
+  return sum;
+}
+
+/* { dg-final { scan-assembler-not "\\.loc 1 \[6789\] 0" } } */
+/* { dg-final { scan-assembler-times "\\.loc 1 18 0" 1 } } */
+/* { dg-final { scan-assembler-times "\\.loc 1 20 0" 1 } } */
diff --git a/gcc/tree-stdarg.c b/gcc/tree-stdarg.c
index 08d10b5..65fe9f9 100644
--- a/gcc/tree-stdarg.c
+++ b/gcc/tree-stdarg.c
@@ -1031,6 +1031,7 @@ expand_ifn_va_arg_1 (function *fun)
   bool modified = false;
   basic_block bb;
   gimple_stmt_iterator i;
+  location_t saved_location;
 
   FOR_EACH_BB_FN (bb, fun)
     for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i))
@@ -1051,6 +1052,8 @@ expand_ifn_va_arg_1 (function *fun)
 	ap = build_fold_indirect_ref (ap);
 
 	push_gimplify_context (false);
+	saved_location = input_location;
+	input_location = gimple_location (stmt);
 
 	/* Make it easier for the backends by protecting the valist argument
 	   from multiple evaluations.  */
@@ -1081,6 +1084,7 @@ expand_ifn_va_arg_1 (function *fun)
 	else
 	  gimplify_expr (&expr, &pre, &post, is_gimple_lvalue, fb_lvalue);
 
+	input_location = saved_location;
 	pop_gimplify_context (NULL);
 
 	gimple_seq_add_seq (&pre, post);
-- 
1.9.1