[Mesa-dev] [PATCH 25/31] i965: Use bitmask/ffs to iterate used vertex attributes.

[Mathias.Froehlich at gmx.net]

From: Mathias Fröhlich <mathias.froehlich at web.de>

Replaces an iterate and test bit in a bitmask loop by a
loop only iterating over the bits set in the bitmask.

v2: Use _mesa_bit_scan{,64} instead of open coding.

Reviewed-by: Brian Paul <brianp at vmware.com>
Signed-off-by: Mathias Fröhlich <Mathias.Froehlich at web.de>
---
 src/mesa/drivers/dri/i965/brw_draw.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_draw.c b/src/mesa/drivers/dri/i965/brw_draw.c
index fa3ff5f..32beb1c 100644
--- a/src/mesa/drivers/dri/i965/brw_draw.c
+++ b/src/mesa/drivers/dri/i965/brw_draw.c
@@ -301,16 +301,15 @@ brw_merge_inputs(struct brw_context *brw,
    }
 
    if (brw->gen < 8 && !brw->is_haswell) {
-      struct gl_program *vp = &ctx->VertexProgram._Current->Base;
+      GLbitfield64 mask = ctx->VertexProgram._Current->Base.InputsRead;
       /* Prior to Haswell, the hardware can't natively support GL_FIXED or
        * 2_10_10_10_REV vertex formats.  Set appropriate workaround flags.
        */
-      for (i = 0; i < VERT_ATTRIB_MAX; i++) {
-         if (!(vp->InputsRead & BITFIELD64_BIT(i)))
-            continue;
-
+      while (mask) {
          uint8_t wa_flags = 0;
 
+         i = _mesa_bit_scan64(&mask);
+
          switch (brw->vb.inputs[i].glarray->Type) {
 
          case GL_FIXED:
-- 
2.5.5