2008-04-14  Alan Modra  <amodra@bigpond.net.au>

	PR target/35907
	* config/rs6000/rs6000.c (rs6000_emit_epilogue): Restore Altivec
	registers using saved backchain as base instead of sp.  Restore
	Altivec registers and VRSAVE before increasing sp if they are saved
	below red zone.

	* gcc.target/powerpc/pr35907.c: New test.

--- gcc/config/rs6000/rs6000.c.jj	2008-04-16 09:43:10.000000000 +0200
+++ gcc/config/rs6000/rs6000.c	2008-04-16 10:05:34.000000000 +0200
@@ -16380,11 +16380,23 @@ rs6000_emit_epilogue (int sibcall)
   if (info->push_p)
     sp_offset = info->total_size;
 
-  /* Restore AltiVec registers if needed.  */
-  if (TARGET_ALTIVEC_ABI && info->altivec_size != 0)
+  /* Restore AltiVec registers if we must do so before adjusting the
+     stack.  */
+  if (TARGET_ALTIVEC_ABI
+      && info->altivec_size != 0
+      && DEFAULT_ABI != ABI_V4
+      && info->altivec_save_offset < (TARGET_32BIT ? -220 : -288))
     {
       int i;
 
+      if (use_backchain_to_restore_sp)
+	{
+	  frame_reg_rtx = gen_rtx_REG (Pmode, 11);
+	  emit_move_insn (frame_reg_rtx,
+			  gen_rtx_MEM (Pmode, sp_reg_rtx));
+	  sp_offset = 0;
+	}
+
       for (i = info->first_altivec_reg_save; i <= LAST_ALTIVEC_REGNO; ++i)
 	if (info->vrsave_mask & ALTIVEC_REG_BIT (i))
 	  {
@@ -16404,19 +16416,54 @@ rs6000_emit_epilogue (int sibcall)
 	  }
     }
 
+  /* Restore VRSAVE if we must do so before adjusting the stack.  */
+  if (TARGET_ALTIVEC
+      && TARGET_ALTIVEC_VRSAVE
+      && info->vrsave_mask != 0
+      && DEFAULT_ABI != ABI_V4
+      && info->vrsave_save_offset < (TARGET_32BIT ? -220 : -288))
+    {
+      rtx addr, mem, reg;
+
+      if (use_backchain_to_restore_sp
+	  && frame_reg_rtx == sp_reg_rtx)
+	{
+	  frame_reg_rtx = gen_rtx_REG (Pmode, 11);
+	  emit_move_insn (frame_reg_rtx,
+			  gen_rtx_MEM (Pmode, sp_reg_rtx));
+	  sp_offset = 0;
+	}
+
+      addr = gen_rtx_PLUS (Pmode, frame_reg_rtx,
+			   GEN_INT (info->vrsave_save_offset + sp_offset));
+      mem = gen_frame_mem (SImode, addr);
+      reg = gen_rtx_REG (SImode, 12);
+      emit_move_insn (reg, mem);
+
+      emit_insn (generate_set_vrsave (reg, info, 1));
+    }
+
   /* If we have a frame pointer, a call to alloca,  or a large stack
      frame, restore the old stack pointer using the backchain.  Otherwise,
      we know what size to update it with.  */
   if (use_backchain_to_restore_sp)
     {
-      /* Under V.4, don't reset the stack pointer until after we're done
-	 loading the saved registers.  */
-      if (DEFAULT_ABI == ABI_V4)
-	frame_reg_rtx = gen_rtx_REG (Pmode, 11);
+      if (frame_reg_rtx != sp_reg_rtx)
+	{
+	  emit_move_insn (sp_reg_rtx, frame_reg_rtx);
+	  frame_reg_rtx = sp_reg_rtx;
+	}
+      else
+	{
+	  /* Under V.4, don't reset the stack pointer until after we're done
+	     loading the saved registers.  */
+	  if (DEFAULT_ABI == ABI_V4)
+	    frame_reg_rtx = gen_rtx_REG (Pmode, 11);
 
-      emit_move_insn (frame_reg_rtx,
-		      gen_rtx_MEM (Pmode, sp_reg_rtx));
-      sp_offset = 0;
+	  emit_move_insn (frame_reg_rtx,
+			  gen_rtx_MEM (Pmode, sp_reg_rtx));
+	  sp_offset = 0;
+	}
     }
   else if (info->push_p
 	   && DEFAULT_ABI != ABI_V4
@@ -16430,9 +16477,39 @@ rs6000_emit_epilogue (int sibcall)
       sp_offset = 0;
     }
 
-  /* Restore VRSAVE if needed.  */
-  if (TARGET_ALTIVEC && TARGET_ALTIVEC_VRSAVE
-      && info->vrsave_mask != 0)
+  /* Restore AltiVec registers if we have not done so already.  */
+  if (TARGET_ALTIVEC_ABI
+      && info->altivec_size != 0
+      && (DEFAULT_ABI == ABI_V4
+	  || info->altivec_save_offset >= (TARGET_32BIT ? -220 : -288)))
+    {
+      int i;
+
+      for (i = info->first_altivec_reg_save; i <= LAST_ALTIVEC_REGNO; ++i)
+	if (info->vrsave_mask & ALTIVEC_REG_BIT (i))
+	  {
+	    rtx addr, areg, mem;
+
+	    areg = gen_rtx_REG (Pmode, 0);
+	    emit_move_insn
+	      (areg, GEN_INT (info->altivec_save_offset
+			      + sp_offset
+			      + 16 * (i - info->first_altivec_reg_save)));
+
+	    /* AltiVec addressing mode is [reg+reg].  */
+	    addr = gen_rtx_PLUS (Pmode, frame_reg_rtx, areg);
+	    mem = gen_frame_mem (V4SImode, addr);
+
+	    emit_move_insn (gen_rtx_REG (V4SImode, i), mem);
+	  }
+    }
+
+  /* Restore VRSAVE if we have not done so already.  */
+  if (TARGET_ALTIVEC
+      && TARGET_ALTIVEC_VRSAVE
+      && info->vrsave_mask != 0
+      && (DEFAULT_ABI == ABI_V4
+	  || info->vrsave_save_offset >= (TARGET_32BIT ? -220 : -288)))
     {
       rtx addr, mem, reg;
 
--- gcc/testsuite/gcc.target/powerpc/pr35907.c.jj	2008-04-16 10:04:23.000000000 +0200
+++ gcc/testsuite/gcc.target/powerpc/pr35907.c	2008-04-16 10:04:58.000000000 +0200
@@ -0,0 +1,60 @@
+/* PR target/35907 */
+/* { dg-do run { target powerpc*-*-* } } */
+/* { dg-require-effective-target powerpc_altivec_ok } */
+/* { dg-options "-O2 -maltivec" } */
+
+#include "altivec_check.h"
+
+#define vector __attribute__((vector_size (16)))
+union
+{
+  vector int k;
+  int c[16];
+} u, v, w;
+vector int m;
+
+void __attribute__((noinline))
+bar (void *i, vector int j)
+{
+  asm volatile ("" : : "r" (i), "r" (&j) : "memory");
+}
+
+int __attribute__((noinline))
+foo (int i, vector int j)
+{
+  char *p = __builtin_alloca (64 + i);
+  m += u.k;
+  v.k = m;
+  w.k = j;
+  if (__builtin_memcmp (&v.c, &w.c, 16) != 0)
+    __builtin_abort ();
+  j += u.k;
+  bar (p, j);
+  j += u.k;
+  bar (p, j);
+  return 0;
+}
+
+void
+main1 (void)
+{
+  vector int l;
+  int i;
+  for (i = 0; i < 4; i++)
+    u.c[i] = i;
+  l = u.k;
+  if (foo (64, l))
+    __builtin_abort ();
+  l += u.k;
+  if (foo (64, l))
+    __builtin_abort ();
+}
+
+int
+main ()
+{
+  altivec_check ();
+  main1 ();
+  exit (0);
+}
+