Mesa (master): gallium/auxiliary: Use exp2(x) instead of pow(2.0, x).

[Matt Turner]

Module: Mesa
Branch: master
Commit: c67ce2bd3b27a26d7f5665f296d307c0de39b720
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=c67ce2bd3b27a26d7f5665f296d307c0de39b720

Author: Matt Turner <mattst88 at gmail.com>
Date:   Mon Jul 13 15:19:54 2015 -0700

gallium/auxiliary: Use exp2(x) instead of pow(2.0, x).

---

 src/gallium/auxiliary/util/u_format_rgb9e5.h |    6 +++---
 src/gallium/auxiliary/util/u_math.c          |    2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/gallium/auxiliary/util/u_format_rgb9e5.h b/src/gallium/auxiliary/util/u_format_rgb9e5.h
index 973e542..1c12a66 100644
--- a/src/gallium/auxiliary/util/u_format_rgb9e5.h
+++ b/src/gallium/auxiliary/util/u_format_rgb9e5.h
@@ -115,8 +115,8 @@ static inline unsigned float3_to_rgb9e5(const float rgb[3])
    exp_shared = MAX2(-RGB9E5_EXP_BIAS-1, rgb9e5_FloorLog2(maxrgb)) + 1 + RGB9E5_EXP_BIAS;
    assert(exp_shared <= RGB9E5_MAX_VALID_BIASED_EXP);
    assert(exp_shared >= 0);
-   /* This pow function could be replaced by a table. */
-   denom = pow(2, exp_shared - RGB9E5_EXP_BIAS - RGB9E5_MANTISSA_BITS);
+   /* This exp2 function could be replaced by a table. */
+   denom = exp2(exp_shared - RGB9E5_EXP_BIAS - RGB9E5_MANTISSA_BITS);
 
    maxm = (int) floor(maxrgb / denom + 0.5);
    if (maxm == MAX_RGB9E5_MANTISSA+1) {
@@ -154,7 +154,7 @@ static inline void rgb9e5_to_float3(unsigned rgb, float retval[3])
 
    v.raw = rgb;
    exponent = v.field.biasedexponent - RGB9E5_EXP_BIAS - RGB9E5_MANTISSA_BITS;
-   scale = (float) pow(2, exponent);
+   scale = exp2f(exponent);
 
    retval[0] = v.field.r * scale;
    retval[1] = v.field.g * scale;
diff --git a/src/gallium/auxiliary/util/u_math.c b/src/gallium/auxiliary/util/u_math.c
index ae9e951..c58af91 100644
--- a/src/gallium/auxiliary/util/u_math.c
+++ b/src/gallium/auxiliary/util/u_math.c
@@ -48,7 +48,7 @@ init_pow2_table(void)
 {
    int i;
    for (i = 0; i < POW2_TABLE_SIZE; i++)
-      pow2_table[i] = (float) pow(2.0, (i - POW2_TABLE_OFFSET) / POW2_TABLE_SCALE);
+      pow2_table[i] = exp2f((i - POW2_TABLE_OFFSET) / POW2_TABLE_SCALE);
 }