Patchwork Fix PR tree-optimization/45612

login
register
mail settings
Submitter Eric Botcazou
Date Oct. 8, 2010, 9:03 p.m.
Message ID <201010082303.31700.ebotcazou@adacore.com>
Download mbox | patch
Permalink /patch/67289/
State New
Headers show

Comments

Eric Botcazou - Oct. 8, 2010, 9:03 p.m.
Hi,

this is the Ada bootstrap failure on SPARC and PA introduced a month ago: the 
compiler emits an undefined label for g-debpoo.adb at -O2.  Partial inlining 
decides to split the Dereference procedure between a label and its address 
and then inlines back the broken out part into the rest of the procedure, thus 
yielding again the original procedure.  The twist is that the reinstantiated 
label address references a new label and not the original one.

Besides the usual rant about this sheer waste of time and memory,
  http://gcc.gnu.org/ml/gcc-patches/2010-06/msg02947.html
I think that such a split point between a label and its address is invalid.

Tested on i586-suse-linux and sparc-sun-solaris2.10, OK for mainline?


2010-10-08  Eric Botcazou  <ebotcazou@adacore.com>

	PR tree-optimization/45612
	* ipa-split.c (test_nonssa_use): Remove bogus ATTRIBUTE_UNUSED.
	Test LABEL_DECLs as well.  Fix formatting issues.
	(verify_non_ssa_vars): Return false for a GIMPLE_LABEL statement
	whose label is present in NON_SSA_VARS.
	(mark_nonssa_use): Remove bogus ATTRIBUTE_UNUSED.  Handle LABEL_DECLs 
	as well.  Fix formatting issues.
	(visit_bb): Fix typos and formatting issue.
Richard Guenther - Oct. 9, 2010, 10:47 a.m.
On Fri, Oct 8, 2010 at 11:03 PM, Eric Botcazou <ebotcazou@adacore.com> wrote:
> Hi,
>
> this is the Ada bootstrap failure on SPARC and PA introduced a month ago: the
> compiler emits an undefined label for g-debpoo.adb at -O2.  Partial inlining
> decides to split the Dereference procedure between a label and its address
> and then inlines back the broken out part into the rest of the procedure, thus
> yielding again the original procedure.  The twist is that the reinstantiated
> label address references a new label and not the original one.
>
> Besides the usual rant about this sheer waste of time and memory,
>  http://gcc.gnu.org/ml/gcc-patches/2010-06/msg02947.html
> I think that such a split point between a label and its address is invalid.
>
> Tested on i586-suse-linux and sparc-sun-solaris2.10, OK for mainline?

Ok.  Do you have a testcase btw?

Thanks,
Richard.

>
> 2010-10-08  Eric Botcazou  <ebotcazou@adacore.com>
>
>        PR tree-optimization/45612
>        * ipa-split.c (test_nonssa_use): Remove bogus ATTRIBUTE_UNUSED.
>        Test LABEL_DECLs as well.  Fix formatting issues.
>        (verify_non_ssa_vars): Return false for a GIMPLE_LABEL statement
>        whose label is present in NON_SSA_VARS.
>        (mark_nonssa_use): Remove bogus ATTRIBUTE_UNUSED.  Handle LABEL_DECLs
>        as well.  Fix formatting issues.
>        (visit_bb): Fix typos and formatting issue.
>
>
> --
> Eric Botcazou
>
Eric Botcazou - Oct. 9, 2010, 10:52 a.m.
> Ok.  Do you have a testcase btw?

Thanks.  No, I didn't try, there are heuristics coming into play all over the 
place and the file was small enough.  I'm sure Jan will quickly find one.

Patch

Index: ipa-split.c
===================================================================
--- ipa-split.c	(revision 164827)
+++ ipa-split.c	(working copy)
@@ -132,29 +132,34 @@  struct split_point best_split_point;
 
 static tree find_retval (basic_block return_bb);
 
-/* Callback for walk_stmt_load_store_addr_ops.  If T is non-ssa automatic
+/* Callback for walk_stmt_load_store_addr_ops.  If T is non-SSA automatic
    variable, check it if it is present in bitmap passed via DATA.  */
 
 static bool
-test_nonssa_use (gimple stmt ATTRIBUTE_UNUSED, tree t,
-	         void *data ATTRIBUTE_UNUSED)
+test_nonssa_use (gimple stmt ATTRIBUTE_UNUSED, tree t, void *data)
 {
   t = get_base_address (t);
 
-  if (t && !is_gimple_reg (t)
-      && ((TREE_CODE (t) == VAR_DECL
+  if (!t || is_gimple_reg (t))
+    return false;
+
+  if (TREE_CODE (t) == PARM_DECL
+      || (TREE_CODE (t) == VAR_DECL
 	  && auto_var_in_fn_p (t, current_function_decl))
-	  || (TREE_CODE (t) == RESULT_DECL)
-	  || (TREE_CODE (t) == PARM_DECL)))
+      || TREE_CODE (t) == RESULT_DECL
+      || TREE_CODE (t) == LABEL_DECL)
     return bitmap_bit_p ((bitmap)data, DECL_UID (t));
 
-  /* For DECL_BY_REFERENCE, the return value is actually pointer.  We want to pretend
-     that the value pointed to is actual result decl.  */
-  if (t && (TREE_CODE (t) == MEM_REF || INDIRECT_REF_P (t))
+  /* For DECL_BY_REFERENCE, the return value is actually a pointer.  We want
+     to pretend that the value pointed to is actual result decl.  */
+  if ((TREE_CODE (t) == MEM_REF || INDIRECT_REF_P (t))
       && TREE_CODE (TREE_OPERAND (t, 0)) == SSA_NAME
       && TREE_CODE (SSA_NAME_VAR (TREE_OPERAND (t, 0))) == RESULT_DECL
       && DECL_BY_REFERENCE (DECL_RESULT (current_function_decl)))
-    return bitmap_bit_p ((bitmap)data, DECL_UID (DECL_RESULT (current_function_decl)));
+    return
+      bitmap_bit_p ((bitmap)data,
+		    DECL_UID (DECL_RESULT (current_function_decl)));
+
   return false;
 }
 
@@ -173,8 +178,8 @@  dump_split_point (FILE * file, struct sp
   dump_bitmap (file, current->ssa_names_to_pass);
 }
 
-/* Look for all BBs in header that might lead to split part and verify that
-   they are not defining any of SSA vars used by split part. 
+/* Look for all BBs in header that might lead to the split part and verify
+   that they are not defining any non-SSA var used by the split part.
    Parameters are the same as for consider_split.  */
 
 static bool
@@ -186,7 +191,7 @@  verify_non_ssa_vars (struct split_point
   edge e;
   edge_iterator ei;
   bool ok = true;
-  
+
   FOR_EACH_EDGE (e, ei, current->entry_bb->preds)
     if (e->src != ENTRY_BLOCK_PTR
 	&& !bitmap_bit_p (current->split_bbs, e->src->index))
@@ -194,7 +199,7 @@  verify_non_ssa_vars (struct split_point
         VEC_safe_push (basic_block, heap, worklist, e->src);
 	bitmap_set_bit (seen, e->src->index);
       }
-  
+
   while (!VEC_empty (basic_block, worklist))
     {
       gimple_stmt_iterator bsi;
@@ -210,21 +215,29 @@  verify_non_ssa_vars (struct split_point
 	  }
       for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
 	{
-	  if (is_gimple_debug (gsi_stmt (bsi)))
+	  gimple stmt = gsi_stmt (bsi);
+	  if (is_gimple_debug (stmt))
 	    continue;
 	  if (walk_stmt_load_store_addr_ops
-	      (gsi_stmt (bsi), non_ssa_vars, test_nonssa_use,
-	       test_nonssa_use, test_nonssa_use))
+	      (stmt, non_ssa_vars, test_nonssa_use, test_nonssa_use,
+	       test_nonssa_use))
 	    {
 	      ok = false;
 	      goto done;
 	    }
+	  if (gimple_code (stmt) == GIMPLE_LABEL
+	      && test_nonssa_use (stmt, gimple_label_label (stmt),
+				  non_ssa_vars))
+	  {
+	    ok = false;
+	    goto done;
+	  }
 	}
       for (bsi = gsi_start_phis (bb); !gsi_end_p (bsi); gsi_next (&bsi))
 	{
 	  if (walk_stmt_load_store_addr_ops
-	      (gsi_stmt (bsi), non_ssa_vars, test_nonssa_use,
-	       test_nonssa_use, test_nonssa_use))
+	      (gsi_stmt (bsi), non_ssa_vars, test_nonssa_use, test_nonssa_use,
+	       test_nonssa_use))
 	    {
 	      ok = false;
 	      goto done;
@@ -542,13 +555,12 @@  find_retval (basic_block return_bb)
   return NULL;
 }
 
-/* Callback for walk_stmt_load_store_addr_ops.  If T is non-ssa automatic
-   variable, mark it as used in bitmap passed via DATA. 
+/* Callback for walk_stmt_load_store_addr_ops.  If T is non-SSA automatic
+   variable, mark it as used in bitmap passed via DATA.
    Return true when access to T prevents splitting the function.  */
 
 static bool
-mark_nonssa_use (gimple stmt ATTRIBUTE_UNUSED, tree t,
-	         void *data ATTRIBUTE_UNUSED)
+mark_nonssa_use (gimple stmt ATTRIBUTE_UNUSED, tree t, void *data)
 {
   t = get_base_address (t);
 
@@ -560,21 +572,27 @@  mark_nonssa_use (gimple stmt ATTRIBUTE_U
   if (TREE_CODE (t) == PARM_DECL)
     {
       if (dump_file && (dump_flags & TDF_DETAILS))
-	fprintf (dump_file, "Can not split use of non-ssa function parameter.\n");
+	fprintf (dump_file,
+		 "Cannot split: use of non-ssa function parameter.\n");
       return true;
     }
 
-  if ((TREE_CODE (t) == VAR_DECL && auto_var_in_fn_p (t, current_function_decl))
-      || (TREE_CODE (t) == RESULT_DECL))
+  if ((TREE_CODE (t) == VAR_DECL
+       && auto_var_in_fn_p (t, current_function_decl))
+      || TREE_CODE (t) == RESULT_DECL
+      || TREE_CODE (t) == LABEL_DECL)
     bitmap_set_bit ((bitmap)data, DECL_UID (t));
 
-  /* For DECL_BY_REFERENCE, the return value is actually pointer.  We want to pretend
-     that the value pointed to is actual result decl.  */
-  if (t && (TREE_CODE (t) == MEM_REF || INDIRECT_REF_P (t))
+  /* For DECL_BY_REFERENCE, the return value is actually a pointer.  We want
+     to pretend that the value pointed to is actual result decl.  */
+  if ((TREE_CODE (t) == MEM_REF || INDIRECT_REF_P (t))
       && TREE_CODE (TREE_OPERAND (t, 0)) == SSA_NAME
       && TREE_CODE (SSA_NAME_VAR (TREE_OPERAND (t, 0))) == RESULT_DECL
       && DECL_BY_REFERENCE (DECL_RESULT (current_function_decl)))
-    return bitmap_bit_p ((bitmap)data, DECL_UID (DECL_RESULT (current_function_decl)));
+    return
+      bitmap_bit_p ((bitmap)data,
+		    DECL_UID (DECL_RESULT (current_function_decl)));
+
   return false;
 }
 
@@ -617,13 +635,13 @@  visit_bb (basic_block bb, basic_block re
 	  && stmt_can_throw_external (stmt))
 	{
 	  if (dump_file && (dump_flags & TDF_DETAILS))
-	    fprintf (dump_file, "Can not split external resx.\n");
+	    fprintf (dump_file, "Cannot split: external resx.\n");
 	  can_split = false;
 	}
       if (gimple_code (stmt) == GIMPLE_EH_DISPATCH)
 	{
 	  if (dump_file && (dump_flags & TDF_DETAILS))
-	    fprintf (dump_file, "Can not split eh dispatch.\n");
+	    fprintf (dump_file, "Cannot split: eh dispatch.\n");
 	  can_split = false;
 	}
 
@@ -642,12 +660,13 @@  visit_bb (basic_block bb, basic_block re
 	  case BUILT_IN_APPLY:
 	  case BUILT_IN_VA_START:
 	    if (dump_file && (dump_flags & TDF_DETAILS))
-	      fprintf (dump_file, "Can not split builtin_apply and va_start.\n");
+	      fprintf (dump_file,
+		       "Cannot split: builtin_apply and va_start.\n");
 	    can_split = false;
 	    break;
 	  case BUILT_IN_EH_POINTER:
 	    if (dump_file && (dump_flags & TDF_DETAILS))
-	      fprintf (dump_file, "Can not split builtin_eh_pointer.\n");
+	      fprintf (dump_file, "Cannot split: builtin_eh_pointer.\n");
 	    can_split = false;
 	    break;
 	  default: