dpow_NaN_V2.patch

diff --git a/src/backend/utils/adt/float.c b/src/backend/utils/adt/float.c
index 6522c08..1483d9f 100644
--- a/src/backend/utils/adt/float.c
+++ b/src/backend/utils/adt/float.c
@@ -1570,10 +1570,14 @@ dpow(PG_FUNCTION_ARGS)
 	 * using something different from our floor() test to decide it's
 	 * invalid).  Other platforms (HPPA) return errno == ERANGE and a large
 	 * (HUGE_VAL) but finite result to signal overflow.
+	 *
+	 * Note that some versions of Visual Studio set errno to EDOM when 
+	 * arg1 or arg2 is a NaN. 
+	 * So we need to except those cases here.
 	 */
 	errno = 0;
 	result = pow(arg1, arg2);
-	if (errno == EDOM && isnan(result))
+	if (errno == EDOM && isnan(result) && !isnan(arg1) && !isnan(arg2))
 	{
 		if ((fabs(arg1) > 1 && arg2 >= 0) || (fabs(arg1) < 1 && arg2 < 0))
 			/* The sign of Inf is not significant in this case. */
diff --git a/src/test/regress/expected/float8.out b/src/test/regress/expected/float8.out
index 20c985e..ede9aaf 100644
--- a/src/test/regress/expected/float8.out
+++ b/src/test/regress/expected/float8.out
@@ -340,6 +340,36 @@ SELECT power(float8 '144', float8 '0.5');
     12
 (1 row)
 
+SELECT power(float8 'NaN', float8 '0.5');
+ power 
+-------
+   NaN
+(1 row)
+
+SELECT power(float8 '144', float8 'NaN');
+ power 
+-------
+   NaN
+(1 row)
+
+SELECT power(float8 'NaN', float8 'NaN');
+ power 
+-------
+   NaN
+(1 row)
+
+SELECT power(float8 '1',float8 'NaN');
+ power 
+-------
+     1
+(1 row)
+
+SELECT power(float8 'NaN',float8 '0');
+ power 
+-------
+     1
+(1 row)
+
 -- take exp of ln(f.f1)
 SELECT '' AS three, f.f1, exp(ln(f.f1)) AS exp_ln_f1
    FROM FLOAT8_TBL f
diff --git a/src/test/regress/sql/float8.sql b/src/test/regress/sql/float8.sql
index 215e7a4..9d1d607 100644
--- a/src/test/regress/sql/float8.sql
+++ b/src/test/regress/sql/float8.sql
@@ -108,6 +108,11 @@ SELECT '' AS three, f.f1, |/f.f1 AS sqrt_f1
 
 -- power
 SELECT power(float8 '144', float8 '0.5');
+SELECT power(float8 'NaN', float8 '0.5');
+SELECT power(float8 '144', float8 'NaN');
+SELECT power(float8 'NaN', float8 'NaN');
+SELECT power(float8 '1',float8 'NaN');
+SELECT power(float8 'NaN',float8 '0');
 
 -- take exp of ln(f.f1)
 SELECT '' AS three, f.f1, exp(ln(f.f1)) AS exp_ln_f1