Add mjsunit tests for optimization of float min/max.

test/mjsunit/compiler/optimize_max.js

+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax
+
+var DOUBLE_ZERO = %AllocateHeapNumber();
+var SMI_ZERO = 0;
+var MINUS_ZERO = -0.0;
+
+function max1(a, b) {
+  a = +a;
+  b = +b;
+  return +(a < b ? b : a);
+}
+
+function max2(a, b) {
+  a = +a;
+  b = +b;
+  return a < b ? b : a;
+}
+
+for (f of [max1, max2]) {
+  for (var i = 0; i < 5; i++) {
+    assertEquals(4, f(3, 4));
+    assertEquals(4, f(4, 3));
+    assertEquals(4.3, f(3.3, 4.3));
+    assertEquals(4.4, f(4.4, 3.4));
+
+    assertEquals(Infinity, 1 / f(SMI_ZERO, MINUS_ZERO));
+    assertEquals(Infinity, 1 / f(DOUBLE_ZERO, MINUS_ZERO));
+    assertEquals(-Infinity, 1 / f(MINUS_ZERO, SMI_ZERO));
+    assertEquals(-Infinity, 1 / f(MINUS_ZERO, DOUBLE_ZERO));
+
+    assertEquals(NaN, f(NaN, NaN));
+    assertEquals(3, f(3, NaN));
+    assertEquals(NaN, f(NaN, 3));
+  }
+}
+
+function max3(a, b) {
+  a = +a;
+  b = +b;
+  return +(a > b ? a : b);
+}
+
+function max4(a, b) {
+  a = +a;
+  b = +b;
+  return a > b ? a : b;
+}
+
+for (f of [max3, max4]) {
+  for (var i = 0; i < 5; i++) {
+    assertEquals(4, f(3, 4));
+    assertEquals(4, f(4, 3));
+    assertEquals(4.3, f(3.3, 4.3));
+    assertEquals(4.4, f(4.4, 3.4));
+
+    assertEquals(-Infinity, 1 / f(SMI_ZERO, MINUS_ZERO));
+    assertEquals(-Infinity, 1 / f(DOUBLE_ZERO, MINUS_ZERO));
+    assertEquals(Infinity, 1 / f(MINUS_ZERO, SMI_ZERO));
+    assertEquals(Infinity, 1 / f(MINUS_ZERO, DOUBLE_ZERO));
+
+    assertEquals(NaN, f(NaN, NaN));
+    assertEquals(NaN, f(3, NaN));
+    assertEquals(3, f(NaN, 3));
+  }
+}