diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 92e6b580859..f9ce2f45701 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,7 @@
+2010-08-11  Richard Henderson  <rth@redhat.com>
+
+	* config/i386/i386.h (HARD_REGNO_CALL_PART_CLOBBERED): New.
+
 2010-08-11  Nick Clifton  <nickc@redhat.com>
 
 	* config/stormy16/stormy16-lib2.c (__cmpsi2): New function.
diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h
index a2acc7131f7..7fd874b93f8 100644
--- a/gcc/config/i386/i386.h
+++ b/gcc/config/i386/i386.h
@@ -1104,6 +1104,12 @@ enum target_cpu_default
    : (MODE) == QImode && (REGNO) > BX_REG && !TARGET_64BIT ? SImode 	\
    : (MODE))
 
+/* The only ABI that saves SSE registers across calls is Win64 (thus no
+   need to check the current ABI here), and with AVX enabled Win64 only
+   guarantees that the low 16 bytes are saved.  */
+#define HARD_REGNO_CALL_PART_CLOBBERED(REGNO, MODE)             \
+  (SSE_REGNO_P (REGNO) && GET_MODE_SIZE (MODE) > 16)
+
 /* Specify the registers used for certain standard purposes.
    The values of these macros are register numbers.  */