[llvm-commits] [test-suite] r94310 - /test-suite/trunk/SingleSource/Benchmarks/Misc/dt.c

[Chris Lattner]

Author: lattner
Date: Sat Jan 23 11:50:04 2010
New Revision: 94310

URL: http://llvm.org/viewvc/llvm-project?rev=94310&view=rev
Log:
a random little benchmark that could benefit from loop interchange
and better alias analysis of posix_memalign.

Added:
    test-suite/trunk/SingleSource/Benchmarks/Misc/dt.c

Added: test-suite/trunk/SingleSource/Benchmarks/Misc/dt.c
URL: http://llvm.org/viewvc/llvm-project/test-suite/trunk/SingleSource/Benchmarks/Misc/dt.c?rev=94310&view=auto

==============================================================================
--- test-suite/trunk/SingleSource/Benchmarks/Misc/dt.c (added)
+++ test-suite/trunk/SingleSource/Benchmarks/Misc/dt.c Sat Jan 23 11:50:04 2010
@@ -0,0 +1,51 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+
+enum {
+  ITERATIONS = 131072,
+  size = 2048
+};
+
+static inline void
+double_array_divs_variable(double * __restrict dvec1,
+                           double * __restrict dvec2){
+  long i, j;
+  for(j = 0; j < ITERATIONS; j++)
+    for(i = 0; i < size; i++)
+      dvec1[i] /= dvec2[i];
+  
+// Can use loop interchange to turn this into:
+//  for(i = 0; i < size; i++) {
+//    double tmp1 = dvec1[i];
+//    double tmp2 = dvec2[i];
+//    for(j = 0; j < ITERATIONS; j++)
+//      tmp1 /= tmp2;
+//    dvec1[i] = tmp1;
+//  }
+
+// Can then hoist 1/tmp2 out of the loop if -ffast-math is enabled.
+}
+
+int main(int argc, char *argv[]) {
+  double	*dvec1, *dvec2;
+  long i;
+
+  posix_memalign((void**)&dvec1, 16, size * sizeof(double));
+  posix_memalign((void**)&dvec2, 16, size * sizeof(double));
+
+  printf( " %i iterations of each test. ", ITERATIONS );
+  printf( " inner loop / array size %i.\n", size );
+
+  // With better alias analysis of posix_memalign, we'd avoid reloading
+  // dvec1/dvec2 each time through the loop.
+  for( i = 0; i < size; i++ ) {
+          dvec1[i] = 1.0000001 * cosf((float)(size - i));
+          dvec2[i] = 1.0  + 0.0000000001 * sinf((float)i);
+  }
+
+  double_array_divs_variable( dvec1, dvec2 );
+  printf("%f\n", dvec1[0]);
+  return 0;
+}
+