Fix mips32 dspr2 build warnings.

Change-Id: Iadbb91ca1905318f094fdfae95f2c4db87943842
diff --git a/aom_dsp/mips/convolve8_avg_dspr2.c b/aom_dsp/mips/convolve8_avg_dspr2.c
index 298065a..3574da1 100644
--- a/aom_dsp/mips/convolve8_avg_dspr2.c
+++ b/aom_dsp/mips/convolve8_avg_dspr2.c
@@ -407,6 +407,11 @@
   uint32_t tp1, tp2, tn1;
   uint32_t tp3, tp4, tn2;
 
+  (void)filter_x;
+  (void)filter_x_stride;
+  (void)filter_y;
+  (void)filter_y_stride;
+
   /* prefetch data to cache memory */
   prefetch_load(src);
   prefetch_load(src + 32);
diff --git a/aom_dsp/mips/convolve8_dspr2.c b/aom_dsp/mips/convolve8_dspr2.c
index c871702..dd4bc82 100644
--- a/aom_dsp/mips/convolve8_dspr2.c
+++ b/aom_dsp/mips/convolve8_dspr2.c
@@ -1304,6 +1304,8 @@
   int32_t intermediate_height = ((h * y_step_q4) >> 4) + 7;
   uint32_t pos = 38;
 
+  (void)x_step_q4;
+
   assert(x_step_q4 == 16);
   assert(y_step_q4 == 16);
   assert(((const int32_t *)filter_x)[1] != 0x800000);
@@ -1400,6 +1402,11 @@
                              int w, int h) {
   int x, y;
 
+  (void)filter_x;
+  (void)filter_x_stride;
+  (void)filter_y;
+  (void)filter_y_stride;
+
   /* prefetch data to cache memory */
   prefetch_load(src);
   prefetch_load(src + 32);
diff --git a/aom_dsp/mips/intrapred16_dspr2.c b/aom_dsp/mips/intrapred16_dspr2.c
index dc8f2020..7c221ae 100644
--- a/aom_dsp/mips/intrapred16_dspr2.c
+++ b/aom_dsp/mips/intrapred16_dspr2.c
@@ -17,6 +17,8 @@
   int32_t tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7, tmp8;
   int32_t tmp9, tmp10, tmp11, tmp12, tmp13, tmp14, tmp15, tmp16;
 
+  (void)above;
+
   __asm__ __volatile__(
       "lb         %[tmp1],      (%[left])                    \n\t"
       "lb         %[tmp2],      1(%[left])                   \n\t"
diff --git a/aom_dsp/mips/intrapred4_dspr2.c b/aom_dsp/mips/intrapred4_dspr2.c
index 44652dc..0a21979 100644
--- a/aom_dsp/mips/intrapred4_dspr2.c
+++ b/aom_dsp/mips/intrapred4_dspr2.c
@@ -15,6 +15,7 @@
 void aom_h_predictor_4x4_dspr2(uint8_t *dst, ptrdiff_t stride,
                                const uint8_t *above, const uint8_t *left) {
   int32_t tmp1, tmp2, tmp3, tmp4;
+  (void)above;
 
   __asm__ __volatile__(
       "lb         %[tmp1],      (%[left])                    \n\t"
diff --git a/aom_dsp/mips/intrapred8_dspr2.c b/aom_dsp/mips/intrapred8_dspr2.c
index 98bdb08..d42a77c 100644
--- a/aom_dsp/mips/intrapred8_dspr2.c
+++ b/aom_dsp/mips/intrapred8_dspr2.c
@@ -15,6 +15,7 @@
 void aom_h_predictor_8x8_dspr2(uint8_t *dst, ptrdiff_t stride,
                                const uint8_t *above, const uint8_t *left) {
   int32_t tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7, tmp8;
+  (void)above;
 
   __asm__ __volatile__(
       "lb         %[tmp1],      (%[left])                   \n\t"
diff --git a/aom_dsp/mips/inv_txfm_dspr2.h b/aom_dsp/mips/inv_txfm_dspr2.h
index 8a85e26..c698351 100644
--- a/aom_dsp/mips/inv_txfm_dspr2.h
+++ b/aom_dsp/mips/inv_txfm_dspr2.h
@@ -24,10 +24,12 @@
 #endif
 
 #if HAVE_DSPR2
+/* Note: this macro expects a local int32_t named out to exist, and will write
+ * to that variable. */
 #define DCT_CONST_ROUND_SHIFT_TWICE_COSPI_16_64(input)                         \
   ({                                                                           \
                                                                                \
-    int32_t tmp, out;                                                          \
+    int32_t tmp;                                                               \
     int dct_cost_rounding = DCT_CONST_ROUNDING;                                \
     int in = input;                                                            \
                                                                                \