Restore handling of -0 in the C field of lines in line_construct().

Commit a7dc63d904 inadvertedly removed this bit originally introduced
by 43fe90f66a, causing regression test failures on some platforms,
due to producing {1,-1,-0} instead of {1,-1,0}.

diff --git a/src/backend/utils/adt/geo_ops.c b/src/backend/utils/adt/geo_ops.c
index 1fb2ff2603ca4b4292c195b170feb3b0f791fdc5..621b5c33ef1b1bc1fba98c9eca73a786fa3198d2 100644 (file)
--- a/src/backend/utils/adt/geo_ops.c
+++ b/src/backend/utils/adt/geo_ops.c
@@ -1024,6 +1024,9 @@ line_construct(LINE *result, Point *pt, float8 m)
                result->A = m;
                result->B = -1.0;
                result->C = pt->y - m * pt->x;
+               /* on some platforms, the preceding expression tends to produce -0 */
+               if (result->C == 0.0)
+                       result->C = 0.0;
        }
 }