diff --git a/dl/sp/src/test/test_fft.gyp b/dl/sp/src/test/test_fft.gyp
index c1be018..d9764cc 100644
--- a/dl/sp/src/test/test_fft.gyp
+++ b/dl/sp/src/test/test_fft.gyp
@@ -167,13 +167,16 @@
         'test_float_rfft.c',
         'support/float_rfft_thresholds.h',
       ],
+      'libraries': [
+        '-lm',
+      ],
       'conditions': [
         ['target_arch == "arm" or target_arch == "arm64"', {
           'sources': [
             'support/float_rfft_neon.c',
           ],
         }],
-        ['target_arch == "ia32"', {
+        ['target_arch == "ia32" or target_arch == "x64"', {
           'sources': [
             'support/float_rfft_x86.c',
           ],
@@ -192,8 +195,11 @@
       'sources': [
         'test_fft_time.c',
       ],
+      'libraries': [
+        '-lm',
+      ],
       'conditions': [
-        ['target_arch == "ia32" or target_arch == "arm64" or target_arch == "mipsel"', {
+        ['target_arch == "ia32" or target_arch == "x64" or target_arch == "arm64" or target_arch == "mipsel"', {
           'defines': [
             # Timing test only for float FFTs on x86 and arm64 and MIPSEL.
             'FLOAT_ONLY',
diff --git a/dl/sp/src/test/test_fft_time.c b/dl/sp/src/test/test_fft_time.c
index 6154228..beaa895 100644
--- a/dl/sp/src/test/test_fft_time.c
+++ b/dl/sp/src/test/test_fft_time.c
@@ -11,6 +11,7 @@
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <sys/resource.h>
 #include <sys/time.h>
 #include <unistd.h>
@@ -609,11 +610,11 @@
       GetUserTime(&start_time);
       for (k = 0; k < count; ++k) {
         for (n = 0; n < fft_size; ++n) {
-          if (fabs(x[n].Re) > factor) {
-            factor = fabs(x[n].Re);
+          if (abs(x[n].Re) > factor) {
+            factor = abs(x[n].Re);
           }
-          if (fabs(x[n].Im) > factor) {
-            factor = fabs(x[n].Im);
+          if (abs(x[n].Im) > factor) {
+            factor = abs(x[n].Im);
           }
         }
 
@@ -653,11 +654,11 @@
       GetUserTime(&start_time);
       for (k = 0; k < count; ++k) {
         for (n = 0; n < fft_size; ++n) {
-          if (fabs(x[n].Re) > factor) {
-            factor = fabs(x[n].Re);
+          if (abs(x[n].Re) > factor) {
+            factor = abs(x[n].Re);
           }
-          if (fabs(x[n].Im) > factor) {
-            factor = fabs(x[n].Im);
+          if (abs(x[n].Im) > factor) {
+            factor = abs(x[n].Im);
           }
         }
         factor = ((1 << 18) - 1) / factor;
@@ -791,11 +792,11 @@
       GetUserTime(&start_time);
       for (k = 0; k < count; ++k) {
         for (n = 0; n < fft_size; ++n) {
-          if (fabs(x[n].Re) > factor) {
-            factor = fabs(x[n].Re);
+          if (abs(x[n].Re) > factor) {
+            factor = abs(x[n].Re);
           }
-          if (fabs(x[n].Im) > factor) {
-            factor = fabs(x[n].Im);
+          if (abs(x[n].Im) > factor) {
+            factor = abs(x[n].Im);
           }
         }
 
@@ -835,11 +836,11 @@
       GetUserTime(&start_time);
       for (k = 0; k < count; ++k) {
         for (n = 0; n < fft_size; ++n) {
-          if (fabs(x[n].Re) > factor) {
-            factor = fabs(x[n].Re);
+          if (abs(x[n].Re) > factor) {
+            factor = abs(x[n].Re);
           }
-          if (fabs(x[n].Im) > factor) {
-            factor = fabs(x[n].Im);
+          if (abs(x[n].Im) > factor) {
+            factor = abs(x[n].Im);
           }
         }
         factor = ((1 << 15) - 1) / factor;
@@ -1013,8 +1014,8 @@
          * Spend some time computing the max of the signal, and then scaling it.
          */
         for (n = 0; n < fft_size; ++n) {
-          if (fabs(xr[n]) > factor) {
-            factor = fabs(xr[n]);
+          if (abs(xr[n]) > factor) {
+            factor = abs(xr[n]);
           }
         }
 
@@ -1080,8 +1081,8 @@
          * Spend some time scaling the FFT signal to fixed point.
          */
         for (n = 0; n < fft_size; ++n) {
-          if (fabs(yrTrue[n]) > factor) {
-            factor = fabs(yrTrue[n]);
+          if (abs(yrTrue[n]) > factor) {
+            factor = abs(yrTrue[n]);
           }
         }
         for (n = 0; n < fft_size; ++n) {
@@ -1282,8 +1283,8 @@
          * Spend some time computing the max of the signal, and then scaling it.
          */
         for (n = 0; n < fft_size; ++n) {
-          if (fabs(xr[n]) > factor) {
-            factor = fabs(xr[n]);
+          if (abs(xr[n]) > factor) {
+            factor = abs(xr[n]);
           }
         }
 
@@ -1331,8 +1332,8 @@
          * Spend some time scaling the FFT signal to fixed point.
          */
         for (n = 0; n < fft_size + 2; ++n) {
-          if (fabs(yrTrue[n]) > factor) {
-            factor = fabs(yrTrue[n]);
+          if (abs(yrTrue[n]) > factor) {
+            factor = abs(yrTrue[n]);
           }
         }
         for (n = 0; n < fft_size + 2; ++n) {
diff --git a/dl/sp/src/test/test_util_fft.c b/dl/sp/src/test/test_util_fft.c
index 3deb041..025ee8d 100644
--- a/dl/sp/src/test/test_util_fft.c
+++ b/dl/sp/src/test/test_util_fft.c
@@ -10,6 +10,7 @@
 #include "dl/sp/src/test/test_util.h"
 
 #include "dl/sp/src/test/compare.h"
+#include "dl/sp/src/test/gensig.h"
 
 /*
  * Test results from running either forward or inverse FFT tests