2010-07-08 Richard Guenther <rguenther@suse.de>

	PR tree-optimization/44831
	* tree-ssa-phiprop.c (phiprop_insert_phi): Properly build
	a MEM_REF preserving TBAA info of the original dereference.
	Dereference the original pointer if the address is not
	invariant.
	(propagate_with_phi): Fixup type checks wrt MEM_REFs.  Require
	at least one invariant address that we are going to dereference.

	* gcc.c-torture/compile/pr44831.c: New testcase.
	* gcc.dg/tree-ssa/pr21463.c: Adjust.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@161950 138bc75d-0d04-0410-961f-82ee72b054a4

5 files changed, 65 insertions, 10 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 0d84f29d587..db4f910397b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,15 @@
 2010-07-08  Richard Guenther  <rguenther@suse.de>
 
+	PR tree-optimization/44831
+	* tree-ssa-phiprop.c (phiprop_insert_phi): Properly build
+	a MEM_REF preserving TBAA info of the original dereference.
+	Dereference the original pointer if the address is not
+	invariant.
+	(propagate_with_phi): Fixup type checks wrt MEM_REFs.  Require
+	at least one invariant address that we are going to dereference.
+
+2010-07-08  Richard Guenther  <rguenther@suse.de>
+
 	PR tree-optimization/44861
 	* tree-vect-stmts.c (vectorizable_store): Preserve TBAA
 	information when building MEM_REFs.
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index d332dc4a960..eb8d5f1bc21 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,11 @@
 2010-07-08  Richard Guenther  <rguenther@suse.de>
 
+	PR tree-optimization/44831
+	* gcc.c-torture/compile/pr44831.c: New testcase.
+	* gcc.dg/tree-ssa/pr21463.c: Adjust.
+
+2010-07-08  Richard Guenther  <rguenther@suse.de>
+
 	PR tree-optimization/44861
 	* g++.dg/vect/pr44861.cc: New testcase.
 
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr44831.c b/gcc/testsuite/gcc.c-torture/compile/pr44831.c
new file mode 100644
index 00000000000..5539583deb0
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr44831.c
@@ -0,0 +1,15 @@
+typedef unsigned char UCHAR, *PUCHAR;
+typedef void *HANDLE;
+typedef struct _NCB {
+    UCHAR ncb_reserve[10];
+} NCB, *PNCB;
+struct NBCmdQueue {
+    PNCB head;
+};
+PNCB *NBCmdQueueFindNBC(struct NBCmdQueue *queue, PNCB ncb)
+{
+  PNCB *ret = &queue->head;
+  while (ret && *ret != ncb)
+    ret = (PNCB *)((*ret)->ncb_reserve + sizeof(HANDLE));
+}
+
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr21463.c b/gcc/testsuite/gcc.dg/tree-ssa/pr21463.c
index f490bf61e5a..3f63cdd8e8c 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr21463.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr21463.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O -fdump-tree-phiprop" } */
+/* { dg-options "-O -fdump-tree-phiprop-details" } */
 
 struct f
 {
@@ -16,5 +16,5 @@ int g(int i, int c, struct f *ff, int g)
   return *t;
 }
 
-/* { dg-final { scan-tree-dump-not "\\*t" "phiprop" } } */
+/* { dg-final { scan-tree-dump-times "Inserting PHI for result of load" 1 "phiprop" } } */
 /* { dg-final { cleanup-tree-dump "phiprop" } } */
diff --git a/gcc/tree-ssa-phiprop.c b/gcc/tree-ssa-phiprop.c
index 6595515e1ad..84f22b956ed 100644
--- a/gcc/tree-ssa-phiprop.c
+++ b/gcc/tree-ssa-phiprop.c
@@ -187,10 +187,17 @@ phiprop_insert_phi (basic_block bb, gimple phi, gimple use_stmt,
 	}
       else
 	{
+	  tree rhs = gimple_assign_rhs1 (use_stmt);
 	  gcc_assert (TREE_CODE (old_arg) == ADDR_EXPR);
-	  old_arg = TREE_OPERAND (old_arg, 0);
-	  new_var = create_tmp_reg (TREE_TYPE (old_arg), NULL);
-	  tmp = gimple_build_assign (new_var, unshare_expr (old_arg));
+	  new_var = create_tmp_reg (TREE_TYPE (rhs), NULL);
+	  if (!is_gimple_min_invariant (old_arg))
+	    old_arg = PHI_ARG_DEF_FROM_EDGE (phi, e);
+	  else
+	    old_arg = unshare_expr (old_arg);
+	  tmp = gimple_build_assign (new_var,
+				     fold_build2 (MEM_REF, TREE_TYPE (rhs),
+						  old_arg,
+						  TREE_OPERAND (rhs, 1)));
 	  gcc_assert (is_gimple_reg (new_var));
 	  add_referenced_var (new_var);
 	  new_var = make_ssa_name (new_var, tmp);
@@ -246,6 +253,8 @@ propagate_with_phi (basic_block bb, gimple phi, struct phiprop_d *phivn,
   use_operand_p arg_p, use;
   ssa_op_iter i;
   bool phi_inserted;
+  tree type = NULL_TREE;
+  bool one_invariant = false;
 
   if (!POINTER_TYPE_P (TREE_TYPE (ptr))
       || !is_gimple_reg_type (TREE_TYPE (TREE_TYPE (ptr))))
@@ -268,16 +277,29 @@ propagate_with_phi (basic_block bb, gimple phi, struct phiprop_d *phivn,
 	    return false;
 	  arg = gimple_assign_rhs1 (def_stmt);
 	}
-      if ((TREE_CODE (arg) != ADDR_EXPR
-	   /* Avoid to have to decay *&a to a[0] later.  */
-	   || !is_gimple_reg_type (TREE_TYPE (TREE_OPERAND (arg, 0))))
+      if (TREE_CODE (arg) != ADDR_EXPR
 	  && !(TREE_CODE (arg) == SSA_NAME
 	       && SSA_NAME_VERSION (arg) < n
 	       && phivn[SSA_NAME_VERSION (arg)].value != NULL_TREE
+	       && (!type
+		   || types_compatible_p
+		       (type, TREE_TYPE (phivn[SSA_NAME_VERSION (arg)].value)))
 	       && phivn_valid_p (phivn, arg, bb)))
 	return false;
+      if (!type
+	  && TREE_CODE (arg) == SSA_NAME)
+	type = TREE_TYPE (phivn[SSA_NAME_VERSION (arg)].value);
+      if (TREE_CODE (arg) == ADDR_EXPR
+	  && is_gimple_min_invariant (arg))
+	one_invariant = true;
     }
 
+  /* If we neither have an address of a decl nor can reuse a previously
+     inserted load, do not hoist anything.  */
+  if (!one_invariant
+      && !type)
+    return false;
+
   /* Find a dereferencing use.  First follow (single use) ssa
      copy chains for ptr.  */
   while (single_imm_use (ptr, &use, &use_stmt)
@@ -298,8 +320,9 @@ propagate_with_phi (basic_block bb, gimple phi, struct phiprop_d *phivn,
 	    && gimple_assign_rhs_code (use_stmt) == MEM_REF
 	    && TREE_OPERAND (gimple_assign_rhs1 (use_stmt), 0) == ptr
 	    && integer_zerop (TREE_OPERAND (gimple_assign_rhs1 (use_stmt), 1))
-	    && types_compatible_p (TREE_TYPE (gimple_assign_rhs1 (use_stmt)),
-				   TREE_TYPE (TREE_TYPE (ptr)))
+	    && (!type
+		|| types_compatible_p
+		     (TREE_TYPE (gimple_assign_lhs (use_stmt)), type))
 	    /* We cannot replace a load that may throw or is volatile.  */
 	    && !stmt_can_throw_internal (use_stmt)))
 	continue;
@@ -319,6 +342,7 @@ propagate_with_phi (basic_block bb, gimple phi, struct phiprop_d *phivn,
       if (!phi_inserted)
 	{
 	  res = phiprop_insert_phi (bb, phi, use_stmt, phivn, n);
+	  type = TREE_TYPE (res);
 
 	  /* Remember the value we created for *ptr.  */
 	  phivn[SSA_NAME_VERSION (ptr)].value = res;