glsl2: fix bug in atan(y, x) function

When x==0, the result was wrong.  Fixes piglit glsl-fs-atan-1.shader_test

1 files changed, 3 insertions, 7 deletions

diff --git a/src/glsl/builtins/ir/atan b/src/glsl/builtins/ir/atan
index 84048293870..04e1898f9f3 100644
--- a/src/glsl/builtins/ir/atan
+++ b/src/glsl/builtins/ir/atan
@@ -80,13 +80,9 @@
 
       )
       (
-        (if (expression bool >= (var_ref y) (constant float (0.000000)) ) (
-          (assign (constant bool (1)) (var_ref r)  (constant float (1.570796)) ) 
-        )
-        (
-          (assign (constant bool (1)) (var_ref r)  (constant float (-1.570796)) ) 
-        ))
-
+        (declare () float sgn)
+        (assign (constant bool (1)) (var_ref sgn) (expression float sign (var_ref y)))
+        (assign (constant bool (1)) (var_ref r) (expression float * (var_ref sgn) (constant float (1.5707965))))
       ))
 
       (return (var_ref r) )