eina_matrix: optimize multiply and inverse calls by actually using the shortcut

We had this nice shortcuts for multiply and inverse with the identity matrix.
Pity we never used it! The EINA_MATRIX_TYPE_IDENTITY is coming from an enum
without and direct assignments to its internals. Being the first item in the
enum it is most likely will be 0 which makes the whole bitwise AND zero and thus
the optimized path will never get called. If our compiler now decides hew wants
to handle enums differently and does not assign the 0 to the first item this
bitwise operation will be even more screwed. What we really want is to check is
if the type we get for the matrix matches EINA_MATRIX_TYPE_IDENTITY. So better
do this. Made me look into matrix multply and inverse. Fun!

Thanks to smatch for poiting this out.

diff --git a/src/lib/eina/eina_matrix.c b/src/lib/eina/eina_matrix.c
index 90493d3..7a1469c 100644 (file)
--- a/src/lib/eina/eina_matrix.c
+++ b/src/lib/eina/eina_matrix.c
@@ -991,13 +991,13 @@ EAPI void
 eina_matrix4_multiply(Eina_Matrix4 *out, const Eina_Matrix4 *mat_a,
                            const Eina_Matrix4 *mat_b)
 {
-   if (eina_matrix4_type_get(mat_a) & EINA_MATRIX_TYPE_IDENTITY)
+   if (eina_matrix4_type_get(mat_a) == EINA_MATRIX_TYPE_IDENTITY)
      {
         eina_matrix4_copy(out, mat_b);
         return;
      }
 
-   if (eina_matrix4_type_get(mat_b) & EINA_MATRIX_TYPE_IDENTITY)
+   if (eina_matrix4_type_get(mat_b) == EINA_MATRIX_TYPE_IDENTITY)
      {
         eina_matrix4_copy(out, mat_a);
         return;
@@ -1085,13 +1085,13 @@ eina_matrix3_copy(Eina_Matrix3 *dst, const Eina_Matrix3 *src)
 EAPI void
 eina_matrix3_multiply(Eina_Matrix3 *out, const Eina_Matrix3 *mat_a, const Eina_Matrix3 *mat_b)
 {
-   if (eina_matrix3_type_get(mat_a) & EINA_MATRIX_TYPE_IDENTITY)
+   if (eina_matrix3_type_get(mat_a) == EINA_MATRIX_TYPE_IDENTITY)
      {
         eina_matrix3_copy(out, mat_b);
         return;
      }
 
-   if (eina_matrix3_type_get(mat_b) & EINA_MATRIX_TYPE_IDENTITY)
+   if (eina_matrix3_type_get(mat_b) == EINA_MATRIX_TYPE_IDENTITY)
      {
         eina_matrix3_copy(out, mat_a);
         return;
@@ -1206,7 +1206,7 @@ eina_matrix2_inverse(Eina_Matrix2 *out, const Eina_Matrix2 *mat)
 {
    double         det;
 
-   if (eina_matrix2_type_get(mat) & EINA_MATRIX_TYPE_IDENTITY)
+   if (eina_matrix2_type_get(mat) == EINA_MATRIX_TYPE_IDENTITY)
      {
         eina_matrix2_copy(out, mat);
         return;
@@ -1250,13 +1250,13 @@ eina_matrix2_copy(Eina_Matrix2 *dst, const Eina_Matrix2 *src)
 EAPI void
 eina_matrix2_multiply(Eina_Matrix2 *out, const Eina_Matrix2 *mat_a, const Eina_Matrix2 *mat_b)
 {
-   if (eina_matrix2_type_get(mat_a) & EINA_MATRIX_TYPE_IDENTITY)
+   if (eina_matrix2_type_get(mat_a) == EINA_MATRIX_TYPE_IDENTITY)
      {
         eina_matrix2_copy(out, mat_b);
         return;
      }
 
-   if (eina_matrix2_type_get(mat_b) & EINA_MATRIX_TYPE_IDENTITY)
+   if (eina_matrix2_type_get(mat_b) == EINA_MATRIX_TYPE_IDENTITY)
      {
         eina_matrix2_copy(out, mat_a);
         return;