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Getting gcc to use cmovs rather than branches in alg_quant()

Speeds up CELT encoding by around 5% on x86

--- a/celt/vq.c

+++ b/celt/vq.c

@@ -185,12 +185,10 @@

    /* Get rid of the sign */

    sum = 0;

    j=0; do {

-      if (X[j]>0)

-         signx[j]=1;

-      else {

-         signx[j]=-1;

-         X[j]=-X[j];

-      }

+      /* OPT: Make sure the following two lines result in conditional moves

+         rather than branches. */

+      signx[j] = X[j]>0 ? 1 : -1;

+      X[j] = ABS16(X[j]);

       iy[j] = 0;

       y[j] = 0;

    } while (++j<N);

@@ -306,8 +304,9 @@

    j=0;

    do {

       X[j] = MULT16_16(signx[j],X[j]);

-      if (signx[j] < 0)

-         iy[j] = -iy[j];

+      /* OPT: Make sure your compiler uses a conditional move here rather than

+         a branch. */

+      iy[j] = signx[j] < 0 ? -iy[j] : iy[j];

    } while (++j<N);

    encode_pulses(iy, N, K, enc);