Reviewers: yanggou_chromium.org,
Description:
[fdlibm] Inline coefficients for __kernel_sin and __kernel_cos.
Loading the coefficients from a the constants typed array is currently
blocking inlining MathSin and MathCos into TurboFan generated code,
because there is no type feedback and hence TurboFan has to generate a
LOAD_IC for every coefficient.
[email protected]
Please review this at https://codereview.chromium.org/989133002/
Base URL: https://chromium.googlesource.com/v8/v8.git@master
Affected files (+19, -15 lines):
M src/third_party/fdlibm/fdlibm.js
Index: src/third_party/fdlibm/fdlibm.js
diff --git a/src/third_party/fdlibm/fdlibm.js
b/src/third_party/fdlibm/fdlibm.js
index
880446990536b62a633fced0ba3b446c9801b396..e93db8d6f3f56a8ee20f9cc6552c5218f3e54473
100644
--- a/src/third_party/fdlibm/fdlibm.js
+++ b/src/third_party/fdlibm/fdlibm.js
@@ -141,16 +141,18 @@ endmacro
// then 3 2
// sin(x) = X + (S1*X + (X *(r-Y/2)+Y))
//
-macro KSIN(x)
-kMath[7+x]
-endmacro
+const S1 = -1.66666666666666324348e-01;
+const S2 = 8.33333333332248946124e-03;
+const S3 = -1.98412698298579493134e-04;
+const S4 = 2.75573137070700676789e-06;
+const S5 = -2.50507602534068634195e-08;
+const S6 = 1.58969099521155010221e-10;
macro RETURN_KERNELSIN(X, Y, SIGN)
var z = X * X;
var v = z * X;
- var r = KSIN(1) + z * (KSIN(2) + z * (KSIN(3) +
- z * (KSIN(4) + z * KSIN(5))));
- return (X - ((z * (0.5 * Y - v * r) - Y) - v * KSIN(0))) SIGN;
+ var r = S2 + z * (S3 + z * (S4 + z * (S5 + z * S6)));
+ return (X - ((z * (0.5 * Y - v * r) - Y) - v * S1)) SIGN;
endmacro
// __kernel_cos(X, Y)
@@ -185,15 +187,17 @@ endmacro
// magnitude of the latter is at least a quarter of X*X/2,
// thus, reducing the rounding error in the subtraction.
//
-macro KCOS(x)
-kMath[13+x]
-endmacro
+const C1 = 4.16666666666666019037e-02;
+const C2 = -1.38888888888741095749e-03;
+const C3 = 2.48015872894767294178e-05;
+const C4 = -2.75573143513906633035e-07;
+const C5 = 2.08757232129817482790e-09;
+const C6 = -1.13596475577881948265e-11;
macro RETURN_KERNELCOS(X, Y, SIGN)
var ix = %_DoubleHi(X) & 0x7fffffff;
var z = X * X;
- var r = z * (KCOS(0) + z * (KCOS(1) + z * (KCOS(2)+
- z * (KCOS(3) + z * (KCOS(4) + z * KCOS(5))))));
+ var r = z * (C1 + z * (C2 + z * (C3 + z * (C4 + z * (C5 + z * C6)))));
if (ix < 0x3fd33333) { // |x| ~< 0.3
return (1 - (0.5 * z - (z * r - X * Y))) SIGN;
} else {
@@ -336,22 +340,22 @@ function MathCosSlow(x) {
// ECMA 262 - 15.8.2.16
function MathSin(x) {
- x = x * 1; // Convert to number.
+ x = +x; // Convert to number.
if ((%_DoubleHi(x) & 0x7fffffff) <= 0x3fe921fb) {
// |x| < pi/4, approximately. No reduction needed.
RETURN_KERNELSIN(x, 0, /* empty */);
}
- return MathSinSlow(x);
+ return +MathSinSlow(x);
}
// ECMA 262 - 15.8.2.7
function MathCos(x) {
- x = x * 1; // Convert to number.
+ x = +x; // Convert to number.
if ((%_DoubleHi(x) & 0x7fffffff) <= 0x3fe921fb) {
// |x| < pi/4, approximately. No reduction needed.
RETURN_KERNELCOS(x, 0, /* empty */);
}
- return MathCosSlow(x);
+ return +MathCosSlow(x);
}
// ECMA 262 - 15.8.2.18
--
--
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