mesa: use fi_type in vertex attribute code

For 32-bit builds, floating point operations use x86 FPU registers,
not SSE registers.  If we're actually storing an integer in a float
variable, the value might get modified when written to memory.  This
patch changes the VBO code to use the fi_type (float/int union) to
store/copy vertex attributes.

Also, this can improve performance on x86 because moving floats with
integer registers instead of FP registers is faster.

Neil Roberts review:
- include changes on all places that are storing attribute values.
- check with and without -O3 compiler flag.
Brian Paul review:
- use fi_type type instead gl_constant_value type
- fix a bunch of nit-picks.
- fix compiler warnings

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=82668
Signed-off-by: Marius Predut <[email protected]>
Reviewed-by: Brian Paul <[email protected]>

1 files changed, 18 insertions, 16 deletions

diff --git a/src/mesa/main/macros.h b/src/mesa/main/macros.h
index 470d3966e82..da5e8e849a2 100644
--- a/src/mesa/main/macros.h
+++ b/src/mesa/main/macros.h
@@ -171,25 +171,25 @@ extern GLfloat _mesa_ubyte_to_float_color_tab[256];
 	ub = ((GLubyte) F_TO_I((f) * 255.0F))
 #endif
 
-static inline GLfloat INT_AS_FLT(GLint i)
+static fi_type UINT_AS_UNION(GLuint u)
 {
    fi_type tmp;
-   tmp.i = i;
-   return tmp.f;
+   tmp.u = u;
+   return tmp;
 }
 
-static inline GLfloat UINT_AS_FLT(GLuint u)
+static inline fi_type INT_AS_UNION(GLint i)
 {
    fi_type tmp;
-   tmp.u = u;
-   return tmp.f;
+   tmp.i = i;
+   return tmp;
 }
 
-static inline unsigned FLT_AS_UINT(float f)
+static inline fi_type FLOAT_AS_UNION(GLfloat f)
 {
    fi_type tmp;
    tmp.f = f;
-   return tmp.u;
+   return tmp;
 }
 
 /**
@@ -604,24 +604,26 @@ do {				\
  * The default values are chosen based on \p type.
  */
 static inline void
-COPY_CLEAN_4V_TYPE_AS_FLOAT(GLfloat dst[4], int sz, const GLfloat src[4],
+COPY_CLEAN_4V_TYPE_AS_UNION(fi_type dst[4], int sz, const fi_type src[4],
                             GLenum type)
 {
    switch (type) {
    case GL_FLOAT:
-      ASSIGN_4V(dst, 0, 0, 0, 1);
+      ASSIGN_4V(dst, FLOAT_AS_UNION(0), FLOAT_AS_UNION(0),
+                FLOAT_AS_UNION(0), FLOAT_AS_UNION(1));
       break;
    case GL_INT:
-      ASSIGN_4V(dst, INT_AS_FLT(0), INT_AS_FLT(0),
-                     INT_AS_FLT(0), INT_AS_FLT(1));
+      ASSIGN_4V(dst, INT_AS_UNION(0), INT_AS_UNION(0),
+                INT_AS_UNION(0), INT_AS_UNION(1));
       break;
    case GL_UNSIGNED_INT:
-      ASSIGN_4V(dst, UINT_AS_FLT(0), UINT_AS_FLT(0),
-                     UINT_AS_FLT(0), UINT_AS_FLT(1));
+      ASSIGN_4V(dst, UINT_AS_UNION(0), UINT_AS_UNION(0),
+                UINT_AS_UNION(0), UINT_AS_UNION(1));
       break;
    default:
-      ASSIGN_4V(dst, 0.0f, 0.0f, 0.0f, 1.0f); /* silence warnings */
-      assert(!"Unexpected type in COPY_CLEAN_4V_TYPE_AS_FLOAT macro");
+      ASSIGN_4V(dst, FLOAT_AS_UNION(0), FLOAT_AS_UNION(0),
+                FLOAT_AS_UNION(0), FLOAT_AS_UNION(1)); /* silence warnings */
+      assert(!"Unexpected type in COPY_CLEAN_4V_TYPE_AS_UNION macro");
    }
    COPY_SZ_4V(dst, sz, src);
 }