re PR rtl-optimization/35281 (multiply with 0 generated for 64*32->64)

2008-03-11  Paolo Bonzini  <bonzini@gnu.org>

	PR rtl-optimization/35281
	* expr.c (convert_move): Use a new pseudo for the intermediate
	from_mode->word_mode result.

From-SVN: r133116

gcc/ChangeLog

 2008-03-11  Paolo Bonzini  <bonzini@gnu.org>
 
+	PR rtl-optimization/35281
+	* expr.c (convert_move): Use a new pseudo for the intermediate
+	from_mode->word_mode result.
+
+2008-03-11  Paolo Bonzini  <bonzini@gnu.org>
+
         * langhooks-def.h (LANG_HOOKS_CLEAR_BINDING_STACK): Delete.
         * langhooks.h (struct lang_hooks): Delete clear_binding_stack member.
         * toplev.c (compile_file): Don't call it.

gcc/expr.c

@@ -552,15 +552,15 @@ convert_move (rtx to, rtx from, int unsignedp)
 	       && ((code = can_extend_p (to_mode, word_mode, unsignedp))
 		   != CODE_FOR_nothing))
 	{
+	  rtx word_to = gen_reg_rtx (word_mode);
 	  if (REG_P (to))
 	    {
 	      if (reg_overlap_mentioned_p (to, from))
 		from = force_reg (from_mode, from);
 	      emit_insn (gen_rtx_CLOBBER (VOIDmode, to));
 	    }
-	  convert_move (gen_lowpart (word_mode, to), from, unsignedp);
-	  emit_unop_insn (code, to,
-			  gen_lowpart (word_mode, to), equiv_code);
+	  convert_move (word_to, from, unsignedp);
+	  emit_unop_insn (code, to, word_to, equiv_code);
 	  return;
 	}