re PR target/45701 (Fail to prefer using r3 for padding a push/pop multiple to 8-byte alignment)

	PR target/45701
	* config/arm/arm.c (any_sibcall_uses_r3): New function.
	(arm_get_frame_offsets): Use it.

2011-01-25  Yao Qi  <yao@codesourcery.com>

        PR target/45701
        * gcc.target/arm/pr45701-1.c: New test.
        * gcc.target/arm/pr45701-2.c: New test.
	* gcc.target/arm/pr45701-3.c: New test.

From-SVN: r169240

6 files changed, 117 insertions, 2 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ac51239..9b9700e 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2011-01-25  Jakub Jelinek  <jakub@redhat.com>
+
+	PR target/45701
+	* config/arm/arm.c (any_sibcall_uses_r3): New function.
+	(arm_get_frame_offsets): Use it.
+
 2011-01-25  Sebastian Pop  <sebastian.pop@amd.com>
 	    Jakub Jelinek  <jakub@redhat.com>
 
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 3e75d7c..be09282 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -1,6 +1,6 @@
 /* Output routines for GCC for ARM.
    Copyright (C) 1991, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
-   2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
+   2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
    Free Software Foundation, Inc.
    Contributed by Pieter `Tiggr' Schoenmakers (rcpieter@win.tue.nl)
    and Martin Simmons (@harleqn.co.uk).
@@ -15188,6 +15188,31 @@ thumb_force_lr_save (void)
 }
 
 
+/* Return true if r3 is used by any of the tail call insns in the
+   current function.  */
+
+static bool
+any_sibcall_uses_r3 (void)
+{
+  edge_iterator ei;
+  edge e;
+
+  if (!crtl->tail_call_emit)
+    return false;
+  FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
+    if (e->flags & EDGE_SIBCALL)
+      {
+	rtx call = BB_END (e->src);
+	if (!CALL_P (call))
+	  call = prev_nonnote_nondebug_insn (call);
+	gcc_assert (CALL_P (call) && SIBLING_CALL_P (call));
+	if (find_regno_fusage (call, USE, 3))
+	  return true;
+      }
+  return false;
+}
+
+
 /* Compute the distance from register FROM to register TO.
    These can be the arg pointer (26), the soft frame pointer (25),
    the stack pointer (13) or the hard frame pointer (11).
@@ -15352,7 +15377,7 @@ arm_get_frame_offsets (void)
 	  /* If it is safe to use r3, then do so.  This sometimes 
 	     generates better code on Thumb-2 by avoiding the need to
 	     use 32-bit push/pop instructions.  */
-	  if (!crtl->tail_call_emit
+ 	  if (! any_sibcall_uses_r3 ()
 	      && arm_size_return_regs () <= 12
 	      && (offsets->saved_regs_mask & (1 << 3)) == 0)
 	    {
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 7b5efca..9046959 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2011-01-25  Yao Qi  <yao@codesourcery.com>
+
+        PR target/45701
+        * gcc.target/arm/pr45701-1.c: New test.
+        * gcc.target/arm/pr45701-2.c: New test.
+	* gcc.target/arm/pr45701-3.c: New test.
+
 2011-01-25  Sebastian Pop  <sebastian.pop@amd.com>
 	    Jakub Jelinek  <jakub@redhat.com>
 
diff --git a/gcc/testsuite/gcc.target/arm/pr45701-1.c b/gcc/testsuite/gcc.target/arm/pr45701-1.c
new file mode 100644
index 0000000..f94f578
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pr45701-1.c
@@ -0,0 +1,24 @@
+/* { dg-do compile } */
+/* { dg-options "-march=armv7-a -mthumb -Os" }  */
+/* { dg-final { scan-assembler "push\t\{r3" } } */
+/* { dg-final { scan-assembler-not "r8" } } */
+
+extern int hist_verify;
+extern char *pre_process_line (char*);
+extern char* str_cpy (char*, char*);
+extern int str_len (char*);
+extern char* x_malloc (int);
+#define savestring(x) (char *)str_cpy (x_malloc (1 + str_len (x)), (x))
+
+char *
+history_expand_line_internal (char* line)
+{
+  char *new_line;
+  int old_verify;
+
+  old_verify = hist_verify;
+  hist_verify = 0;
+  new_line = pre_process_line (line);
+  hist_verify = old_verify;
+  return (new_line == line) ? savestring (line) : new_line;
+}
diff --git a/gcc/testsuite/gcc.target/arm/pr45701-2.c b/gcc/testsuite/gcc.target/arm/pr45701-2.c
new file mode 100644
index 0000000..68d51781
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pr45701-2.c
@@ -0,0 +1,26 @@
+/* { dg-do compile } */
+/* { dg-options "-march=armv7-a -mthumb -Os" }  */
+/* { dg-final { scan-assembler "push\t\{r3" } } */
+/* { dg-final { scan-assembler-not "r8" } } */
+
+extern int hist_verify;
+extern char *pre_process_line (char*);
+extern char* savestring1 (char*, char*);
+extern char* str_cpy (char*, char*);
+extern int str_len (char*);
+extern char* x_malloc (int);
+#define savestring(x) (char *)str_cpy (x_malloc (1 + str_len (x)), (x))
+
+char *
+history_expand_line_internal (char* line)
+{
+  char *new_line;
+  int old_verify;
+
+  old_verify = hist_verify;
+  hist_verify = 0;
+  new_line = pre_process_line (line);
+  hist_verify = old_verify;
+  /* Two tail calls here, but r3 is not used to pass values.  */
+  return (new_line == line) ? savestring (line) : savestring1 (new_line, line);
+}
diff --git a/gcc/testsuite/gcc.target/arm/pr45701-3.c b/gcc/testsuite/gcc.target/arm/pr45701-3.c
new file mode 100644
index 0000000..8255bae
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pr45701-3.c
@@ -0,0 +1,27 @@
+/* { dg-do compile } */
+/* { dg-options "-march=armv7-a -mthumb -Os" }  */
+/* { dg-final { scan-assembler "push\t.*r8" } } */
+/* { dg-final { scan-assembler-not "push\t*r3" } } */
+
+extern int hist_verify;
+extern char *pre_process_line (char*);
+extern char* savestring1 (char*, char*, int, int);
+extern char* str_cpy (char*, char*);
+extern int str_len (char*);
+extern char* x_malloc (int);
+#define savestring(x) (char *)str_cpy (x_malloc (1 + str_len (x)), (x))
+
+char *
+history_expand_line_internal (char* line)
+{
+  char *new_line;
+  int old_verify;
+
+  old_verify = hist_verify;
+  hist_verify = 0;
+  new_line = pre_process_line (line);
+  hist_verify = old_verify;
+  /* Two tail calls here, but r3 is used to pass values.  */
+  return (new_line == line) ? savestring (line) : 
+    savestring1 (new_line, line, 0, old_verify+1);
+}