Increase precision when finding the remainder after division by pi/2.

test/mjsunit/sin-cos.js

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 // Test Math.sin and Math.cos.
 
+// Flags: --allow-natives-syntax
+
 function sinTest() {
   assertEquals(0, Math.sin(0));
   assertEquals(1, Math.sin(Math.PI / 2));
 }
 
 function cosTest() {
   assertEquals(1, Math.cos(0));
   assertEquals(-1, Math.cos(Math.PI));
 }
 
@@ skipping 94 matching lines @@
 var err_rms = Math.sqrt(squares[0] / test_inputs.length / 2);
 assertTrue(err_rms < 1E-14);
 
 assertEquals(-1, Math.cos({ valueOf: function() { return Math.PI; } }));
 assertEquals(0, Math.sin("0x00000"));
 assertEquals(1, Math.cos("0x00000"));
 assertTrue(isNaN(Math.sin(Infinity)));
 assertTrue(isNaN(Math.cos("-Infinity")));
 assertEquals("Infinity", String(Math.tan(Math.PI/2)));
 assertEquals("-Infinity", String(Math.tan(-Math.PI/2)));
+
+// Assert that the remainder after division by pi is reasonably precise.
+function assertError(expected, x, epsilon) {

[Sven Panne, 2013/11/20 07:38:35]

Can we move this to mjsunit.js under a better name, e.g.
assertEqualsDelta(expected, actual, delta, opt_message)? Or just assertEquals
and dispatch on the third argument (message or delta). See
http://junit.sourceforge.net/javadoc/org/junit/Assert.html#assertEquals(double,
double, double)

+  assertTrue(Math.abs(x - expected) < epsilon);
+}
+
+assertError(0.9367521275331447, Math.cos(1e06), 1E-14);
+assertError(0.8731196226768560, Math.cos(1e10), 1E-04);
+assertError(0.9367521275331447, Math.cos(-1e06), 1E-14);
+assertError(0.8731196226768560, Math.cos(-1e10), 1E-04);
+assertError(-0.3499935021712929, Math.sin(1e06), 1E-14);
+assertError(-0.4875060250875106, Math.sin(1e10), 1E-04);
+assertError(0.3499935021712929, Math.sin(-1e06), 1E-14);
+assertError(0.4875060250875106, Math.sin(-1e10), 1E-04);
+
+// Assert that remainder calculation terminates even for large numbers
+Math.sin(1e40);
+Math.cos(1e50);
+
+
+function no_deopt_on_minus_zero(x) {
+  return Math.sin(x) + Math.cos(x) + Math.tan(x);
+}
+
+no_deopt_on_minus_zero(1);
+no_deopt_on_minus_zero(1);
+%OptimizeFunctionOnNextCall(no_deopt_on_minus_zero);
+no_deopt_on_minus_zero(-0);
+assertOptimized(no_deopt_on_minus_zero);