tree-nrv.c (dest_safe_for_nrv_p): Grok any handled_component_p, SSA_NAMEs, RESULT_DECLs and PARM_DECLs.

	* tree-nrv.c (dest_safe_for_nrv_p): Grok any handled_component_p,
	SSA_NAMEs, RESULT_DECLs and PARM_DECLs.

	* g++.dg/opt/nrv12.C: New test.
	* gcc.target/i386/nrv1.c: New test.

From-SVN: r126200

5 files changed, 64 insertions, 20 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f9f4b24..409799b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2007-07-02  Jakub Jelinek  <jakub@redhat.com>
+
+	* tree-nrv.c (dest_safe_for_nrv_p): Grok any handled_component_p,
+	SSA_NAMEs, RESULT_DECLs and PARM_DECLs.
+
 2007-07-02  Richard Guenther  <rguenther@suse.de>
 
 	* tree-ssa.c (useless_type_conversion_p): Document
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index ae91753..fee89cf 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2007-07-02  Jakub Jelinek  <jakub@redhat.com>
+
+	* g++.dg/opt/nrv12.C: New test.
+	* gcc.target/i386/nrv1.c: New test.
+
 2007-07-02  Ira Rosen  <irar@il.ibm.com>
  
 	PR tree-optimization/32230
diff --git a/gcc/testsuite/g++.dg/opt/nrv12.C b/gcc/testsuite/g++.dg/opt/nrv12.C
new file mode 100644
index 0000000..944dddd
--- /dev/null
+++ b/gcc/testsuite/g++.dg/opt/nrv12.C
@@ -0,0 +1,25 @@
+/* Verify that gimple-level NRV is occurring even for RESULT_DECLs.  *./
+/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
+/* { dg-options "-O -fdump-tree-optimized" } */
+/* { dg-require-effective-target ilp32 } */
+
+struct P
+{
+  long long l;
+  int a;
+  unsigned int b;
+  P(long long x) : l(x) {}
+};
+
+P foo (P);
+P bar (P);
+
+P foo (P x)
+{
+  P y = P (-1LL);
+  y = bar (x);
+  return y;
+}
+
+/* { dg-final { scan-tree-dump-times "return slot optimization" 1 "optimized" } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */
diff --git a/gcc/testsuite/gcc.target/i386/nrv1.c b/gcc/testsuite/gcc.target/i386/nrv1.c
new file mode 100644
index 0000000..5cd8b06
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/nrv1.c
@@ -0,0 +1,12 @@
+/* Verify that gimple-level NRV is occurring even for SSA_NAMEs.  *./
+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-optimized" } */
+/* { dg-require-effective-target ilp32 } */
+
+_Complex double foo (_Complex double x)
+{
+  return __builtin_cexp (x);
+}
+
+/* { dg-final { scan-tree-dump-times "return slot optimization" 1 "optimized" } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */
diff --git a/gcc/tree-nrv.c b/gcc/tree-nrv.c
index 5a0db89..fe812a9 100644
--- a/gcc/tree-nrv.c
+++ b/gcc/tree-nrv.c
@@ -250,26 +250,23 @@ struct tree_opt_pass pass_nrv =
 static bool
 dest_safe_for_nrv_p (tree dest)
 {
-  switch (TREE_CODE (dest))
-    {
-      case VAR_DECL:
-	{
-	  subvar_t subvar;
-	  if (is_call_clobbered (dest))
-	    return false;
-	  for (subvar = get_subvars_for_var (dest);
-	       subvar;
-	       subvar = subvar->next)
-	    if (is_call_clobbered (subvar->var))
-	      return false;
-	  return true;
-	}
-      case ARRAY_REF:
-      case COMPONENT_REF:
-	return dest_safe_for_nrv_p (TREE_OPERAND (dest, 0));
-      default:
-	return false;
-    }
+  subvar_t subvar;
+
+  while (handled_component_p (dest))
+    dest = TREE_OPERAND (dest, 0);
+
+  if (! SSA_VAR_P (dest))
+    return false;
+
+  if (TREE_CODE (dest) == SSA_NAME)
+    dest = SSA_NAME_VAR (dest);
+
+  if (is_call_clobbered (dest))
+    return false;
+  for (subvar = get_subvars_for_var (dest); subvar; subvar = subvar->next)
+    if (is_call_clobbered (subvar->var))
+      return false;
+  return true;
 }
 
 /* Walk through the function looking for GIMPLE_MODIFY_STMTs with calls that