real.c (real_hash): New.

        * real.c (real_hash): New.
        * real.h: Declare it.
        * cse.c (canon_hash): Use it.
        * cselib.c (hash_rtx): Likewise.
        * emit-rtl.c (const_double_htab_hash): Likewise.
        * rtl.h (CONST_DOUBLE_REAL_VALUE): New.
        * varasm.c (struct rtx_const): Reduce vector size; separate
        integer and fp vectors.
        (HASHBITS): Remove.
        (const_hash_1): Rename from const_hash.  Use real_hash.  Do not
        take modulus MAX_HASH_TABLE.
        (const_hash): New.  Do take modulus MAX_HASH_TABLE.
        (output_constant_def): Do not take modulus MAX_HASH_TABLE.
        (SYMHASH): Don't use HASHBITS.
        (decode_rtx_const): Copy only active bits from REAL_VALUE_TYPE.
        Fix CONST_VECTOR thinko wrt fp vectors.  Fix kind comparison.
        (simplify_subtraction): Fix kind comparison.
        (const_hash_rtx): Return unsigned int.  Don't use HASHBITS.
        Use a union to pun integer array.
        * config/rs6000/rs6000.c (rs6000_hash_constant): Use real_hash;
        only hash two words of integral CONST_DOUBLE.

From-SVN: r57356

1 files changed, 41 insertions, 0 deletions

diff --git a/gcc/real.c b/gcc/real.c
index 2c28135..d746ab6 100644
--- a/gcc/real.c
+++ b/gcc/real.c
@@ -2311,6 +2311,47 @@ significand_size (mode)
 
   return fmt->p * fmt->log2_b;
 }
+
+/* Return a hash value for the given real value.  */
+/* ??? The "unsigned int" return value is intended to be hashval_t,
+   but I didn't want to pull hashtab.h into real.h.  */
+
+unsigned int
+real_hash (r)
+     const REAL_VALUE_TYPE *r;
+{
+  unsigned int h;
+  size_t i;
+
+  h = r->class | (r->sign << 2);
+  switch (r->class)
+    {
+    case rvc_zero:
+    case rvc_inf:
+      break;
+
+    case rvc_normal:
+      h |= r->exp << 3;
+      /* FALLTHRU */
+
+    case rvc_nan:
+      if (sizeof(unsigned long) > sizeof(unsigned int))
+	for (i = 0; i < SIGSZ; ++i)
+	  {
+	    unsigned long s = r->sig[i];
+	    h ^= s ^ (s >> (HOST_BITS_PER_LONG / 2));
+	  }
+      else
+	for (i = 0; i < SIGSZ; ++i)
+	  h ^= r->sig[i];
+      break;
+
+    default:
+      abort ();
+    }
+
+  return h;
+}
 
 /* IEEE single-precision format.  */