Index: tools/fpcmp.c
===================================================================
--- tools/fpcmp.c
+++ tools/fpcmp.c
@@ -217,7 +217,8 @@
 
 int diff_files_with_tolerance(const char *path_a, const char *path_b,
                               double absolute_tolerance,
-                              double relative_tolerance) {
+                              double relative_tolerance,
+                              bool ignore_whitespace) {
   /* First, load the file buffers completely into memory. */
   long A_size, B_size;
   char *data_a = load_file(path_a, &A_size);
@@ -246,8 +247,34 @@
 
   while (1) {
     // Scan for the end of file or next difference.
-    while (F1P < File1End && F2P < File2End && *F1P == *F2P)
-      ++F1P, ++F2P;
+    while (F1P < File1End && F2P < File2End) {
+      if (*F1P == *F2P) {
+        ++F1P, ++F2P;
+        continue;
+      }
+
+      // If both chars are whitespace, then we have a
+      // whitespace-only difference (e.g. CR vs. LF).
+      // Without this check, we would be in an infinite loop.
+      if (!ignore_whitespace && isspace(*F1P) && isspace(*F2P))
+        return 1;
+
+      // With whitespace ignored, skip whitespace chars and recheck for
+      // the next difference.
+      if (ignore_whitespace) {
+        if (isspace(*F1P)) {
+          ++F1P;
+          continue;
+        }
+
+        if (isspace(*F2P)) {
+          ++F2P;
+          continue;
+        }
+      }
+
+      break;
+    }
 
     if (F1P >= File1End || F2P >= File2End) break;
 
@@ -296,17 +323,19 @@
 }
 
 void usage() {
-  fprintf(stderr, "usage: %s [-a VALUE] [-r VALUE] <path-A> <path-B>\n\n",
+  fprintf(stderr, "usage: %s [-a VALUE] [-r VALUE] [-i] <path-A> <path-B>\n\n",
           g_program);
   fprintf(stderr, "Compare two files using absolute and relative tolerances\n");
   fprintf(stderr, "when comparing differences between two character\n");
   fprintf(stderr, "which could be real numbers\n");
+  fprintf(stderr, "The -i switch ignores whitespace differences\n");
   exit(2);
 }
 
 int main(int argc, char * const argv[]) {
   double relative_tolerance = 0.0;
   double absolute_tolerance = 0.0;
+  bool ignore_whitespace = false;
   int i;
 
   g_program = argv[0];
@@ -341,6 +370,10 @@
       }
       break;
 
+    case 'i':
+      ignore_whitespace = true;
+      break;
+
     default:
       fprintf(stderr, "error: invalid argument '%s'\n\n", arg);
       usage();
@@ -352,6 +385,6 @@
     usage();
   }
 
-  return diff_files_with_tolerance(argv[i], argv[i + 1],
-                                   absolute_tolerance, relative_tolerance);
+  return diff_files_with_tolerance(argv[i], argv[i + 1], absolute_tolerance,
+                                   relative_tolerance, ignore_whitespace);
 }