diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7862b105683d..a798d85f283a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2008-12-18  Jan Hubicka  <jh@suse.cz>
+	    Kai Tietz <kai.tietz@onevision.com>
+
+	* i386.h (CONDITIONAL_REGISTER_USAGE): Initialize for current function
+	ABI.
+	* i386.c (ix86_call_abi_override): Do not trigger target re-init and
+	do not try to modify call used regs.
+	(ix86_maybe_switch_abi): New function.
+	(TARGET_EXPAND_TO_RTL_HOOK): New macro.
+
 2008-12-18  Kenneth Zadeck <zadeck@naturalbridge.com>
 
 	PR rtl-optimization/37922
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 12e9e5abfe97..824a11dc230b 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -4600,9 +4600,7 @@ extern void init_regs (void);
 
 /* Implementation of call abi switching target hook. Specific to FNDECL
    the specific call register sets are set. See also CONDITIONAL_REGISTER_USAGE
-   for more details.
-   To prevent redudant calls of costy function init_regs (), it checks not to
-   reset register usage for default abi.  */
+   for more details.  */
 void
 ix86_call_abi_override (const_tree fndecl)
 {
@@ -4610,24 +4608,17 @@ ix86_call_abi_override (const_tree fndecl)
     cfun->machine->call_abi = DEFAULT_ABI;
   else
     cfun->machine->call_abi = ix86_function_type_abi (TREE_TYPE (fndecl));
-  if (TARGET_64BIT && cfun->machine->call_abi == MS_ABI)
-    {
-      if (call_used_regs[4 /*RSI*/] != 0 || call_used_regs[5 /*RDI*/] != 0)
-        {
-          call_used_regs[4 /*RSI*/] = 0;
-          call_used_regs[5 /*RDI*/] = 0;
-          init_regs ();
-        }
-    }
-  else if (TARGET_64BIT)
-    {
-      if (call_used_regs[4 /*RSI*/] != 1 || call_used_regs[5 /*RDI*/] != 1)
-        {
-          call_used_regs[4 /*RSI*/] = 1;
-          call_used_regs[5 /*RDI*/] = 1;
-          init_regs ();
-        }
-    }
+}
+
+/* MS and SYSV ABI have different set of call used registers.  Avoid expensive
+   re-initialization of init_regs each time we switch function context since
+   this is needed only during RTL expansion.  */
+static void
+ix86_maybe_switch_abi (void)
+{
+  if (TARGET_64BIT &&
+      call_used_regs[4 /*RSI*/] ==  (cfun->machine->call_abi == MS_ABI))
+    init_regs ();
 }
 
 /* Initialize a variable CUM of type CUMULATIVE_ARGS
@@ -29243,6 +29234,9 @@ ix86_enum_va_list (int idx, const char **pname, tree *ptree)
 #undef TARGET_OPTION_CAN_INLINE_P
 #define TARGET_OPTION_CAN_INLINE_P ix86_can_inline_p
 
+#undef TARGET_EXPAND_TO_RTL_HOOK
+#define TARGET_EXPAND_TO_RTL_HOOK ix86_maybe_switch_abi
+
 struct gcc_target targetm = TARGET_INITIALIZER;
 
 #include "gt-i386.h"
diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h
index 32f793b1cf75..a1da0a754bdf 100644
--- a/gcc/config/i386/i386.h
+++ b/gcc/config/i386/i386.h
@@ -964,7 +964,9 @@ do {									\
 	for (i = FIRST_REX_SSE_REG; i <= LAST_REX_SSE_REG; i++)		\
 	  reg_names[i] = "";						\
       }									\
-    if (TARGET_64BIT && DEFAULT_ABI == MS_ABI)				\
+    if (TARGET_64BIT							\
+        && ((cfun && cfun->machine->call_abi == MS_ABI)			\
+            || (!cfun && DEFAULT_ABI == MS_ABI)))			\
       {									\
         call_used_regs[4 /*RSI*/] = 0;                                  \
         call_used_regs[5 /*RDI*/] = 0;                                  \