Re: [PR67891] drop is_gimple_reg test from set_parm_rtl

[Alexandre Oliva <aoliva at redhat dot com>]

On Nov  3, 2015, Jeff Law <law@redhat.com> wrote:

> On 11/02/2015 06:11 PM, Alexandre Oliva wrote:
>> On Oct 14, 2015, Richard Biener <richard.guenther@gmail.com> wrote:
>>> It looks ok to me but lacks a comment in mark_addressable_1 why we
>>> do this queueing when currently expanding to RTL.
>> 
>>>> +/* Mark X as addressable or queue it up if called during expand.  */
>>>> +
>>>> +static void
>>>> +mark_addressable_1 (tree x)
>> 
>> How about this:
>> 
>> /* Mark X as addressable or queue it up if called during expand.  We
>> don't want to apply it immediately during expand because decls are
>> made addressable at that point due to RTL-only concerns, such as
>> uses of memcpy for block moves, and TREE_ADDRESSABLE changes
>> is_gimple_reg, which might make it seem like a variable that used
>> to be a gimple_reg shouldn't have been an SSA name.  So we queue up
>> this flag setting and only apply it when we're done with GIMPLE and
>> only RTL issues matter.  */
> Sounds good.

Thanks, here's the patch as just installed.

for  gcc/ChangeLog

	* gimple-expr.c: Include hash-set.h and rtl.h.
	(mark_addressable_queue): New var.
	(mark_addressable): Factor actual marking into...
	(mark_addressable_1): ... this.  Queue it up during expand.
	(mark_addressable_2): New.
	(flush_mark_addressable_queue): New.
	* gimple-expr.h (flush_mark_addressable_queue): Declare.
	* cfgexpand.c: Include gimple-expr.h.
	(pass_expand::execute): Flush mark_addressable queue.
---
 gcc/cfgexpand.c   |    3 +++
 gcc/gimple-expr.c |   57 +++++++++++++++++++++++++++++++++++++++++++++++++++--
 gcc/gimple-expr.h |    1 +
 3 files changed, 59 insertions(+), 2 deletions(-)

diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c
index b59ea02..bfbc958 100644
--- a/gcc/cfgexpand.c
+++ b/gcc/cfgexpand.c
@@ -51,6 +51,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "internal-fn.h"
 #include "tree-eh.h"
 #include "gimple-iterator.h"
+#include "gimple-expr.h"
 #include "gimple-walk.h"
 #include "tree-cfg.h"
 #include "tree-dfa.h"
@@ -6368,6 +6369,8 @@ pass_expand::execute (function *fun)
   /* We're done expanding trees to RTL.  */
   currently_expanding_to_rtl = 0;
 
+  flush_mark_addressable_queue ();
+
   FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (fun)->next_bb,
 		  EXIT_BLOCK_PTR_FOR_FN (fun), next_bb)
     {
diff --git a/gcc/gimple-expr.c b/gcc/gimple-expr.c
index 44749b81..f5f9e87 100644
--- a/gcc/gimple-expr.c
+++ b/gcc/gimple-expr.c
@@ -32,6 +32,8 @@ along with GCC; see the file COPYING3.  If not see
 #include "gimplify.h"
 #include "stor-layout.h"
 #include "demangle.h"
+#include "hash-set.h"
+#include "rtl.h"
 
 /* ----- Type related -----  */
 
@@ -817,6 +819,57 @@ is_gimple_mem_ref_addr (tree t)
 		  || decl_address_invariant_p (TREE_OPERAND (t, 0)))));
 }
 
+/* Hold trees marked addressable during expand.  */
+
+static hash_set<tree> *mark_addressable_queue;
+
+/* Mark X as addressable or queue it up if called during expand.  We
+   don't want to apply it immediately during expand because decls are
+   made addressable at that point due to RTL-only concerns, such as
+   uses of memcpy for block moves, and TREE_ADDRESSABLE changes
+   is_gimple_reg, which might make it seem like a variable that used
+   to be a gimple_reg shouldn't have been an SSA name.  So we queue up
+   this flag setting and only apply it when we're done with GIMPLE and
+   only RTL issues matter.  */
+
+static void
+mark_addressable_1 (tree x)
+{
+  if (!currently_expanding_to_rtl)
+    {
+      TREE_ADDRESSABLE (x) = 1;
+      return;
+    }
+
+  if (!mark_addressable_queue)
+    mark_addressable_queue = new hash_set<tree>();
+  mark_addressable_queue->add (x);
+}
+
+/* Adaptor for mark_addressable_1 for use in hash_set traversal.  */
+
+bool
+mark_addressable_2 (tree const &x, void * ATTRIBUTE_UNUSED = NULL)
+{
+  mark_addressable_1 (x);
+  return false;
+}
+
+/* Mark all queued trees as addressable, and empty the queue.  To be
+   called right after clearing CURRENTLY_EXPANDING_TO_RTL.  */
+
+void
+flush_mark_addressable_queue ()
+{
+  gcc_assert (!currently_expanding_to_rtl);
+  if (mark_addressable_queue)
+    {
+      mark_addressable_queue->traverse<void*, mark_addressable_2> (NULL);
+      delete mark_addressable_queue;
+      mark_addressable_queue = NULL;
+    }
+}
+
 /* Mark X addressable.  Unlike the langhook we expect X to be in gimple
    form and we don't do any syntax checking.  */
 
@@ -832,7 +885,7 @@ mark_addressable (tree x)
       && TREE_CODE (x) != PARM_DECL
       && TREE_CODE (x) != RESULT_DECL)
     return;
-  TREE_ADDRESSABLE (x) = 1;
+  mark_addressable_1 (x);
 
   /* Also mark the artificial SSA_NAME that points to the partition of X.  */
   if (TREE_CODE (x) == VAR_DECL
@@ -843,7 +896,7 @@ mark_addressable (tree x)
     {
       tree *namep = cfun->gimple_df->decls_to_pointers->get (x);
       if (namep)
-	TREE_ADDRESSABLE (*namep) = 1;
+	mark_addressable_1 (*namep);
     }
 }
 
diff --git a/gcc/gimple-expr.h b/gcc/gimple-expr.h
index 3d1c89f..2917d2752c 100644
--- a/gcc/gimple-expr.h
+++ b/gcc/gimple-expr.h
@@ -52,6 +52,7 @@ extern bool is_gimple_asm_val (tree);
 extern bool is_gimple_min_lval (tree);
 extern bool is_gimple_call_addr (tree);
 extern bool is_gimple_mem_ref_addr (tree);
+extern void flush_mark_addressable_queue (void);
 extern void mark_addressable (tree);
 extern bool is_gimple_reg_rhs (tree);
 


-- 
Alexandre Oliva, freedom fighter    http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/   FSF Latin America board member
Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer