Reduce call chain of qsort

This will considerably improve the performance of qsort-heavily-used projects
like Android-Pinyin-IME, more discussion:
  https://groups.google.com/forum/#!topic/emscripten-discuss/Ah2CNfQ8ra4
  https://github.com/kripken/emscripten/pull/1437

1 files changed, 43 insertions, 0 deletions

diff --git a/tests/qsort/benchmark.cpp b/tests/qsort/benchmark.cpp
new file mode 100644
index 00000000..950ca437
--- /dev/null
+++ b/tests/qsort/benchmark.cpp
@@ -0,0 +1,43 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <time.h>
+
+typedef unsigned int uint32;
+
+int cmp_uint(const void *i1, const void *i2) {
+  if (*static_cast<const uint32*>(i1) >
+      *static_cast<const uint32*>(i2))
+    return 1;
+
+  if (*static_cast<const uint32*>(i1) <
+      *static_cast<const uint32*>(i2))
+    return -1;
+
+  return 0;
+}
+
+int main() {
+  clock_t start = clock();
+  const size_t TIMES = 10000;
+  for (size_t i = 0; i < TIMES; i++) {
+    const size_t num = 100;
+    uint32 rnd[num] = { \
+      407, 236, 765, 529,  24,  13, 577, 900, 242, 245, \
+      782, 972, 514, 100, 596, 470, 680,  65, 370, 788, \
+       44, 330, 579, 314, 914, 399, 100, 945, 992, 412, \
+      308, 102, 895, 529, 216, 422, 851, 778,  28, 804, \
+      325, 975, 961, 623, 922, 667, 141, 755, 416, 575, \
+      712, 503, 174, 675,  14, 647, 544, 881, 858, 621, \
+       26, 283, 460, 252, 146,  16, 571, 570,  14, 143, \
+      674, 985, 477, 386, 932, 490, 611, 127, 702, 619, \
+      104, 892,  58, 635, 663, 424, 714, 740, 229, 538, \
+      167, 181, 193, 193, 657, 778, 217, 573, 764, 745};
+
+    qsort(rnd, num, sizeof(uint32), cmp_uint);
+  }
+  clock_t end = clock();
+
+  float diff = (((float)end - (float)start) / CLOCKS_PER_SEC ) * 1000;
+  printf("cost %fms\n", diff);
+}
+