Remove the special cases to prevent minus-zero results in float4 and float8

unary minus operators.  We weren't attempting to prevent minus zero anywhere
else; in view of our gradual trend to make the float datatypes more IEEE
standard compliant, we should allow minus zero here rather than disallow it
elsewhere.

We don't, however, expect that all platforms will produce minus zero, so
we need to adjust the one affected regression test to allow both results.

Per discussion of bug #4660.

(In passing, clean up a couple other minor infelicities in float.c.)

1 files changed, 8 insertions, 13 deletions

diff --git a/src/backend/utils/adt/float.c b/src/backend/utils/adt/float.c
index f74367d64c4..6ad06788fc4 100644
--- a/src/backend/utils/adt/float.c
+++ b/src/backend/utils/adt/float.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/float.c,v 1.159 2009/01/01 17:23:49 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/float.c,v 1.160 2009/02/18 19:23:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -576,9 +576,7 @@ float4um(PG_FUNCTION_ARGS)
 	float4		arg1 = PG_GETARG_FLOAT4(0);
 	float4		result;
 
-	result = ((arg1 != 0) ? -(arg1) : arg1);
-
-	CHECKFLOATVAL(result, isinf(arg1), true);
+	result = -arg1;
 	PG_RETURN_FLOAT4(result);
 }
 
@@ -645,9 +643,7 @@ float8um(PG_FUNCTION_ARGS)
 	float8		arg1 = PG_GETARG_FLOAT8(0);
 	float8		result;
 
-	result = ((arg1 != 0) ? -(arg1) : arg1);
-
-	CHECKFLOATVAL(result, isinf(arg1), true);
+	result = -arg1;
 	PG_RETURN_FLOAT8(result);
 }
 
@@ -703,16 +699,16 @@ float8smaller(PG_FUNCTION_ARGS)
 Datum
 float4pl(PG_FUNCTION_ARGS)
 {
-	float8		arg1 = PG_GETARG_FLOAT4(0);
-	float8		arg2 = PG_GETARG_FLOAT4(1);
+	float4		arg1 = PG_GETARG_FLOAT4(0);
+	float4		arg2 = PG_GETARG_FLOAT4(1);
 	float4		result;
 
 	result = arg1 + arg2;
 
 	/*
 	 * There isn't any way to check for underflow of addition/subtraction
-	 * because numbers near the underflow value have been already been to the
-	 * point where we can't detect the that the two values were originally
+	 * because numbers near the underflow value have already been rounded to
+	 * the point where we can't detect that the two values were originally
 	 * different, e.g. on x86, '1e-45'::float4 == '2e-45'::float4 ==
 	 * 1.4013e-45.
 	 */
@@ -757,7 +753,6 @@ float4div(PG_FUNCTION_ARGS)
 				(errcode(ERRCODE_DIVISION_BY_ZERO),
 				 errmsg("division by zero")));
 
-	/* Do division in float8, then check for overflow */
 	result = arg1 / arg2;
 
 	CHECKFLOATVAL(result, isinf(arg1) || isinf(arg2), arg1 == 0);
@@ -2693,7 +2688,7 @@ width_bucket_float8(PG_FUNCTION_ARGS)
 			  errmsg("operand, lower bound and upper bound cannot be NaN")));
 
 	/* Note that we allow "operand" to be infinite */
-	if (is_infinite(bound1) || is_infinite(bound2))
+	if (isinf(bound1) || isinf(bound2))
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_ARGUMENT_FOR_WIDTH_BUCKET_FUNCTION),
 				 errmsg("lower and upper bounds must be finite")));