diff --git a/src/backend/utils/adt/float.c b/src/backend/utils/adt/float.c
index 8aa17e1dcb..e58ee1609c 100644
--- a/src/backend/utils/adt/float.c
+++ b/src/backend/utils/adt/float.c
@@ -1479,14 +1479,15 @@ dpow(PG_FUNCTION_ARGS)
 	 * pow() sets errno only on some platforms, depending on whether it
 	 * follows _IEEE_, _POSIX_, _XOPEN_, or _SVID_, so we try to avoid using
 	 * errno.  However, some platform/CPU combinations return errno == EDOM
-	 * and result == Nan for negative arg1 and very large arg2 (they must be
+	 * and result == NaN for negative arg1 and very large arg2 (they must be
 	 * 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.
+	 * (HUGE_VAL) but finite result to signal overflow.  Also, some versions
+	 * of MSVC return errno == EDOM and result == NaN for NaN inputs.
 	 */
 	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-exp-three-digits-win32.out b/src/test/regress/expected/float8-exp-three-digits-win32.out
index 7e1153308f..3fe50b4bf0 100644
--- a/src/test/regress/expected/float8-exp-three-digits-win32.out
+++ b/src/test/regress/expected/float8-exp-three-digits-win32.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/expected/float8-small-is-zero.out b/src/test/regress/expected/float8-small-is-zero.out
index 26b8378150..46adbe1c4b 100644
--- a/src/test/regress/expected/float8-small-is-zero.out
+++ b/src/test/regress/expected/float8-small-is-zero.out
@@ -344,6 +344,36 @@ 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/expected/float8-small-is-zero_1.out b/src/test/regress/expected/float8-small-is-zero_1.out
index cea27908eb..f215eede10 100644
--- a/src/test/regress/expected/float8-small-is-zero_1.out
+++ b/src/test/regress/expected/float8-small-is-zero_1.out
@@ -344,6 +344,36 @@ 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/expected/float8.out b/src/test/regress/expected/float8.out
index 20c985e5df..7159e78d4a 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 215e7a4784..5510fe9d34 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