re PR target/21501 (ICE in extract_insn, at recog.c:2082)

	PR target/21501
	* arm.c (arm_gen_constant): Sign-extend intermediate values when
	synthesizing a constant of the difference of two immediates.

From-SVN: r99608

gcc/ChangeLog

 2005-05-12  Richard Earnshaw  <richard.earnshaw@arm.com>
 
+	PR target/21501
+	* arm.c (arm_gen_constant): Sign-extend intermediate values when
+	synthesizing a constant of the difference of two immediates.
+
+2005-05-12  Richard Earnshaw  <richard.earnshaw@arm.com>
+
 	* arm/vfp.md (negsf2_vfp): Add alternative using integer registers.
 	(negdf2_vfp): Likewise.  Convert to define_insn_and_split and split
 	the alternatives using integer registers into the appropriate

gcc/config/arm/arm.c

@@ -1920,7 +1920,7 @@ arm_gen_constant (enum rtx_code code, enum machine_mode mode, rtx cond,
 	{
 	  int topshift = clear_sign_bit_copies & ~1;
 
-	  temp1 = ((remainder + (0x00800000 >> topshift))
+	  temp1 = ARM_SIGN_EXTEND ((remainder + (0x00800000 >> topshift))
 				   & (0xff000000 >> topshift));
 
 	  /* If temp1 is zero, then that means the 9 most significant
@@ -1930,7 +1930,7 @@ arm_gen_constant (enum rtx_code code, enum machine_mode mode, rtx cond,
 	  if (temp1 == 0 && topshift != 0)
 	    temp1 = 0x80000000 >> (topshift - 1);
 
-	  temp2 = temp1 - remainder;
+	  temp2 = ARM_SIGN_EXTEND (temp1 - remainder);
 	  
 	  if (const_ok_for_arm (temp2))
 	    {