Subzero: Strength-reduce mul by certain constants.

crosstest/test_strengthreduce_main.cpp

Index: crosstest/test_strengthreduce_main.cpp
diff --git a/crosstest/test_strengthreduce_main.cpp b/crosstest/test_strengthreduce_main.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..2c2aa986ca40b1353316a57c2f2c7024eea4178a
--- /dev/null
+++ b/crosstest/test_strengthreduce_main.cpp
@@ -0,0 +1,65 @@
+//===- subzero/crosstest/test_strengthreduce_main.cpp - Driver for tests --===//
+//
+//                        The Subzero Code Generator
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Driver for crosstesting arithmetic strength-reducing optimizations.
+//
+//===----------------------------------------------------------------------===//
+
+/* crosstest.py --test=test_strengthreduce.cpp \
+   --driver=test_strengthreduce_main.cpp \
+   --prefix=Subzero_ --clang-opt=0 --output=test_strengthreduce */
+
+#include <iostream>
+
+// Include test_strengthreduce.h twice - once normally, and once
+// within the Subzero_ namespace, corresponding to the llc and Subzero
+// translated object files, respectively.
+#include "test_strengthreduce.h"
+namespace Subzero_ {
+#include "test_strengthreduce.h"
+}
+
+int main(int argc, char **argv) {
+  size_t TotalTests = 0;
+  size_t Passes = 0;
+  size_t Failures = 0;
+  static int32_t Values[] = {-100, -50, 0, 1, 8, 123, 0x33333333, 0x77777777};
+  for (size_t i = 0; i < sizeof(Values) / sizeof(*Values); ++i) {
+    int32_t SVal = Values[i];
+    int32_t ResultLlcS, ResultSzS;
+    uint32_t UVal = (uint32_t)Values[i];
+    int32_t ResultLlcU, ResultSzU;
+
+#define X(constant, suffix)                                                    \
+  ResultLlcS = multiplyByConst##suffix(UVal);                                  \
+  ResultSzS = Subzero_::multiplyByConst##suffix(UVal);                         \
+  if (ResultLlcS == ResultSzS) {                                               \
+    ++Passes;                                                                  \
+  } else {                                                                     \
+    ++Failures;                                                                \
+    std::cout << "multiplyByConstS" STR(suffix) "(" << SVal                    \
+              << "): sz=" << ResultSzS << " llc=" << ResultLlcS << "\n";       \
+  }                                                                            \
+  ResultLlcU = multiplyByConst##suffix(UVal);                                  \
+  ResultSzU = Subzero_::multiplyByConst##suffix(UVal);                         \
+  if (ResultLlcU == ResultSzU) {                                               \
+    ++Passes;                                                                  \
+  } else {                                                                     \
+    ++Failures;                                                                \
+    std::cout << "multiplyByConstU" STR(suffix) "(" << UVal                    \
+              << "): sz=" << ResultSzU << " llc=" << ResultLlcU << "\n";       \
+  }
+    CONST_TABLE
+#undef X
+  }
+
+  std::cout << "TotalTests=" << TotalTests << " Passes=" << Passes
+            << " Failures=" << Failures << "\n";
+  return Failures;
+}