commit 592aa40e87285c53229ccf544691611e9c78b578
Author: Kyrylo Tkachov <kyrylo.tkachov@arm.com>
Date:   Wed Aug 13 14:08:02 2014 +0100

    [ARM] Fix %N output modifier

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 5f7cbb1..a48ca4e 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -100,7 +100,6 @@ static void arm_atomic_assign_expand_fenv (tree *hold, tree *clear, tree *update
 static void arm_print_operand (FILE *, rtx, int);
 static void arm_print_operand_address (FILE *, rtx);
 static bool arm_print_operand_punct_valid_p (unsigned char code);
-static const char *fp_const_from_val (REAL_VALUE_TYPE *);
 static arm_cc get_arm_condition_code (rtx);
 static HOST_WIDE_INT int_log2 (HOST_WIDE_INT);
 static const char *output_multi_immediate (rtx *, const char *, const char *,
@@ -17534,17 +17533,6 @@ arm_reorg (void)
 
 /* Routines to output assembly language.  */
 
-/* Return string representation of passed in real value.  */
-static const char *
-fp_const_from_val (REAL_VALUE_TYPE *r)
-{
-  if (!fp_consts_inited)
-    init_fp_table ();
-
-  gcc_assert (REAL_VALUES_EQUAL (*r, value_fp0));
-  return "0";
-}
-
 /* OPERANDS[0] is the entire list of insns that constitute pop,
    OPERANDS[1] is the base register, RETURN_PC is true iff return insn
    is in the list, UPDATE is true iff the list contains explicit
@@ -21533,13 +21521,21 @@ arm_print_operand (FILE *stream, rtx x, int code)
 
     case 'N':
       {
-	REAL_VALUE_TYPE r;
-	REAL_VALUE_FROM_CONST_DOUBLE (r, x);
-	r = real_value_negate (&r);
-	fprintf (stream, "%s", fp_const_from_val (&r));
-      }
-      return;
+        if (CONST_DOUBLE_P (x))
+          {
+            char fpstr[20];
+            REAL_VALUE_TYPE r;
+
+            REAL_VALUE_FROM_CONST_DOUBLE (r, x);
+            r = real_value_negate (&r);
+            real_to_decimal (fpstr, &r, sizeof (fpstr), 0, 1);
+            fprintf (stream, "%s", fpstr);
+          }
+        else
+          output_operand_lossage ("Unsupported operand for code '%c'", code);
 
+        return;
+      }
     /* An integer or symbol address without a preceding # sign.  */
     case 'c':
       switch (GET_CODE (x))
diff --git a/gcc/testsuite/gcc.target/arm/n_output_modifier_1.c b/gcc/testsuite/gcc.target/arm/n_output_modifier_1.c
new file mode 100644
index 0000000..e94914b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/n_output_modifier_1.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_vfp_ok } */
+/* { dg-final { scan-assembler-times "-5.0e-1" 1 } } */
+
+
+int
+foo (int a)
+{
+  int result = 0;
+   __asm__ ("%0, %N1"
+            : "=r"(result)
+            : "Dt"(0.5)
+            : );
+  return result;
+}
+