re PR target/47246 (Invalid immediate offset for Thumb VFP store regression)

2011-01-26  Chung-Lin Tang  <cltang@codesourcery.com>

	PR target/47246
	* config/arm/arm.c (thumb2_legitimate_index_p): Change the
	lower bound of the allowed Thumb-2 coprocessor load/store
	index range to -256. Add explaining comment.

From-SVN: r169271

gcc/ChangeLog

+2011-01-26  Chung-Lin Tang  <cltang@codesourcery.com>
+
+	PR target/47246
+	* config/arm/arm.c (thumb2_legitimate_index_p): Change the
+	lower bound of the allowed Thumb-2 coprocessor load/store
+	index range to -256. Add explaining comment.
+
 2011-01-25  Ian Lance Taylor  <iant@google.com>
 
 	* godump.c (go_define): Improve lexing of macro expansion to only

gcc/config/arm/arm.c

@@ -5786,7 +5786,11 @@ thumb2_legitimate_index_p (enum machine_mode mode, rtx index, int strict_p)
       && (mode == SFmode || mode == DFmode
 	  || (TARGET_MAVERICK && mode == DImode)))
     return (code == CONST_INT && INTVAL (index) < 1024
-	    && INTVAL (index) > -1024
+	    /* Thumb-2 allows only > -256 index range for it's core register
+	       load/stores. Since we allow SF/DF in core registers, we have
+	       to use the intersection between -256~4096 (core) and -1024~1024
+	       (coprocessor).  */
+	    && INTVAL (index) > -256
 	    && (INTVAL (index) & 3) == 0);
 
   if (TARGET_REALLY_IWMMXT && VALID_IWMMXT_REG_MODE (mode))