Fixes some ICEs, and more importantly a miscompilation refered to
in bugzilla #148558 .

Index: gcc/ifcvt.c
===================================================================
--- gcc/ifcvt.c	2006-02-27 14:48:30.475954001 +0100
+++ gcc/ifcvt.c	2006-02-27 14:48:40.881875685 +0100
@@ -1842,7 +1842,7 @@
       || (SMALL_REGISTER_CLASSES
 	  && REGNO (x) < FIRST_PSEUDO_REGISTER))
     {
-      if (no_new_pseudos)
+      if (no_new_pseudos || GET_MODE (x) == BLKmode)
 	return FALSE;
       x = gen_reg_rtx (GET_MODE (GET_CODE (x) == STRICT_LOW_PART
 				 ? XEXP (x, 0) : x));