Fix rounding in Uint8ClampedArray setter.

test/mjsunit/regress/regress-2294.js

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 // Flags: --allow-natives-syntax
 
-// Test inlining at call sites with mismatched arity.
+var clampedArray = new Uint8ClampedArray(10);
 
-function f(a) {
-  return a.x;
+function setElement(i, x) {
+  clampedArray[i] = x;
 }
 
-function g(a, b) {
-  return a.x;
+for (var i = 0; i < 2; i++) {
+  setElement(0, 0.499)
+  assertEquals(0, clampedArray[0]);
+  setElement(0, 0.5)
+  assertEquals(0, clampedArray[0]);
+  setElement(0, 0.501)
+  assertEquals(1, clampedArray[0]);
+  setElement(0, 1.499)
+  assertEquals(1, clampedArray[0]);
+  setElement(0, 1.5)
+  assertEquals(2, clampedArray[0]);
+  setElement(0, 1.501)
+  assertEquals(2, clampedArray[0]);
+  setElement(0, 2.5)
+  assertEquals(2, clampedArray[0]);
+  setElement(0, 3.5)
+  assertEquals(4, clampedArray[0]);
+  setElement(0, 252.5)
+  assertEquals(252, clampedArray[0]);
+  setElement(0, 253.5)
+  assertEquals(254, clampedArray[0]);
+  setElement(0, 254.5)
+  assertEquals(254, clampedArray[0]);
+  setElement(0, 256.5)
+  assertEquals(255, clampedArray[0]);
+  setElement(0, -0.5)
+  assertEquals(0, clampedArray[0]);
+  setElement(0, -1.5)
+  assertEquals(0, clampedArray[0]);
+  %OptimizeFunctionOnNextCall(setElement)

[Yang, 2012/08/22 07:57:07]

setElement may be optimized before the first iteration ends, and you wouldn't be
able to test runtime code for several cases. How about inline all setElement
calls and checks into one large test function? You can call that function a
first time to test runtime code, a second time to make sure type information are
in place for optimization, optimize and run a third time to test optimized code.

[ulan, 2012/08/22 13:48:17]

Done.

 }
-
-function h1(a, b) {
-  return f(a, a) * g(b);
-}
-
-function h2(a, b) {
-  return f(a, a) * g(b);
-}
-
-
-var o = {x: 2};
-
-assertEquals(4, h1(o, o));
-assertEquals(4, h1(o, o));
-assertEquals(4, h2(o, o));
-assertEquals(4, h2(o, o));
-%OptimizeFunctionOnNextCall(h1);
-%OptimizeFunctionOnNextCall(h2);
-assertEquals(4, h1(o, o));
-assertEquals(4, h2(o, o));
-
-var u = {y:0, x:1};
-assertEquals(2, h1(u, o));
-assertEquals(2, h2(o, u));