[Mesa-dev] [PATCH] mesa/format_utils: Add src_bits == dst_bits cases to [us]norm functions

[Jason Ekstrand]

This better ensures that the src_bits == dst_bits case gets optimized away.
---
 src/mesa/main/format_utils.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/mesa/main/format_utils.h b/src/mesa/main/format_utils.h
index 00ec777..65314e6 100644
--- a/src/mesa/main/format_utils.h
+++ b/src/mesa/main/format_utils.h
@@ -99,7 +99,7 @@ _mesa_unorm_to_unorm(unsigned x, unsigned src_bits, unsigned dst_bits)
 {
    if (src_bits < dst_bits) {
       return EXTEND_NORMALIZED_INT(x, src_bits, dst_bits);
-   } else {
+   } else if (src_bits > dst_bits) {
       unsigned src_half = (1 << (src_bits - 1)) - 1;
 
       if (src_bits + dst_bits > sizeof(x) * 8) {
@@ -109,6 +109,8 @@ _mesa_unorm_to_unorm(unsigned x, unsigned src_bits, unsigned dst_bits)
       } else {
          return (x * MAX_UINT(dst_bits) + src_half) / MAX_UINT(src_bits);
       }
+   } else {
+      return x;
    }
 }
 
@@ -151,8 +153,10 @@ _mesa_snorm_to_snorm(int x, unsigned src_bits, unsigned dst_bits)
       return -MAX_INT(dst_bits);
    else if (src_bits < dst_bits)
       return EXTEND_NORMALIZED_INT(x, src_bits - 1, dst_bits - 1);
-   else
+   else if (src_bits > dst_bits)
       return x >> (src_bits - dst_bits);
+   else
+      return x;
 }
 
 static inline unsigned
-- 
2.4.3