expmed.c (expand_mult_highpart_optab): When attempting to use a non-widening…

expmed.c (expand_mult_highpart_optab): When attempting to use a non-widening multiplication in a wider mode...


	* expmed.c (expand_mult_highpart_optab): When attempting to use
	a non-widening multiplication in a wider mode, the operands need
	to be converted (zero or sign extended) to that mode.

From-SVN: r94383

gcc/ChangeLog

+2005-01-28  Roger Sayle  <roger@eyesopen.com>
+
+	* expmed.c (expand_mult_highpart_optab): When attempting to use
+	a non-widening multiplication in a wider mode, the operands need
+	to be converted (zero or sign extended) to that mode.
+
 2005-01-28  Ian Lance Taylor  <ian@airs.com>
 
 	PR middle-end/16558

gcc/expmed.c

@@ -3332,15 +3332,29 @@ expand_mult_highpart_optab (enum machine_mode mode, rtx op0, rtx op1,
     }
 
   /* Try widening the mode and perform a non-widening multiplication.  */
-  moptab = smul_optab;
   if (smul_optab->handlers[wider_mode].insn_code != CODE_FOR_nothing
       && size - 1 < BITS_PER_WORD
       && mul_cost[wider_mode] + shift_cost[mode][size-1] < max_cost)
     {
-      tem = expand_binop (wider_mode, moptab, op0, op1, 0,
+      rtx insns, wop0, wop1;
+
+      /* We need to widen the operands, for example to ensure the
+	 constant multiplier is correctly sign or zero extended.
+	 Use a sequence to clean-up any instructions emitted by
+	 the conversions if things don't work out.  */
+      start_sequence ();
+      wop0 = convert_modes (wider_mode, mode, op0, unsignedp);
+      wop1 = convert_modes (wider_mode, mode, op1, unsignedp);
+      tem = expand_binop (wider_mode, smul_optab, wop0, wop1, 0,
 			  unsignedp, OPTAB_WIDEN);
+      insns = get_insns ();
+      end_sequence ();
+
       if (tem)
-	return extract_high_half (mode, tem);
+	{
+	  emit_insn (insns);
+	  return extract_high_half (mode, tem);
+	}
     }
 
   /* Try widening multiplication of opposite signedness, and adjust.  */