runtime: make complex division c99 compatible
- changes tests to check that the real and imaginary part of the go complex
division result is equal to the result gcc produces for c99
- changes complex division code to satisfy new complex division test
- adds float functions isNan, isFinite, isInf, abs and copysign
in the runtime package
Fixes #14644.
name old time/op new time/op delta
Complex128DivNormal-4 21.8ns ± 6% 13.9ns ± 6% -36.37% (p=0.000 n=20+20)
Complex128DivNisNaN-4 14.1ns ± 1% 15.0ns ± 1% +5.86% (p=0.000 n=20+19)
Complex128DivDisNaN-4 12.5ns ± 1% 16.7ns ± 1% +33.79% (p=0.000 n=19+20)
Complex128DivNisInf-4 10.1ns ± 1% 13.0ns ± 1% +28.25% (p=0.000 n=20+19)
Complex128DivDisInf-4 11.0ns ± 1% 20.9ns ± 1% +90.69% (p=0.000 n=16+19)
ComplexAlgMap-4 86.7ns ± 1% 86.8ns ± 2% ~ (p=0.804 n=20+20)
Change-Id: I261f3b4a81f6cc858bc7ff48f6fd1b39c300abf0
Reviewed-on: https://go-review.googlesource.com/37441
Reviewed-by: Robert Griesemer <gri@golang.org>
diff --git a/test/cmplxdivide.c b/test/cmplxdivide.c
index a475cc2..89a2868 100644
--- a/test/cmplxdivide.c
+++ b/test/cmplxdivide.c
@@ -23,50 +23,63 @@
#define nelem(x) (sizeof(x)/sizeof((x)[0]))
double f[] = {
- 0,
- 1,
- -1,
- 2,
+ 0.0,
+ -0.0,
+ 1.0,
+ -1.0,
+ 2.0,
NAN,
INFINITY,
-INFINITY,
};
-char*
-fmt(double g)
-{
+char* fmt(double g) {
static char buf[10][30];
static int n;
char *p;
-
+
p = buf[n++];
- if(n == 10)
+ if(n == 10) {
n = 0;
+ }
+
sprintf(p, "%g", g);
- if(strcmp(p, "-0") == 0)
- strcpy(p, "negzero");
+
+ if(strcmp(p, "0") == 0) {
+ strcpy(p, "zero");
+ return p;
+ }
+
+ if(strcmp(p, "-0") == 0) {
+ strcpy(p, "-zero");
+ return p;
+ }
+
return p;
}
-int
-iscnan(double complex d)
-{
- return !isinf(creal(d)) && !isinf(cimag(d)) && (isnan(creal(d)) || isnan(cimag(d)));
-}
-
-double complex zero; // attempt to hide zero division from gcc
-
-int
-main(void)
-{
+int main(void) {
int i, j, k, l;
double complex n, d, q;
-
+
printf("// skip\n");
printf("// # generated by cmplxdivide.c\n");
printf("\n");
printf("package main\n");
- printf("var tests = []Test{\n");
+ printf("\n");
+ printf("import \"math\"\n");
+ printf("\n");
+ printf("var (\n");
+ printf("\tnan = math.NaN()\n");
+ printf("\tinf = math.Inf(1)\n");
+ printf("\tzero = 0.0\n");
+ printf(")\n");
+ printf("\n");
+ printf("var tests = []struct {\n");
+ printf("\tf, g complex128\n");
+ printf("\tout complex128\n");
+ printf("}{\n");
+
for(i=0; i<nelem(f); i++)
for(j=0; j<nelem(f); j++)
for(k=0; k<nelem(f); k++)
@@ -74,17 +87,8 @@
n = f[i] + f[j]*I;
d = f[k] + f[l]*I;
q = n/d;
-
- // BUG FIX.
- // Gcc gets the wrong answer for NaN/0 unless both sides are NaN.
- // That is, it treats (NaN+NaN*I)/0 = NaN+NaN*I (a complex NaN)
- // but it then computes (1+NaN*I)/0 = Inf+NaN*I (a complex infinity).
- // Since both numerators are complex NaNs, it seems that the
- // results should agree in kind. Override the gcc computation in this case.
- if(iscnan(n) && d == 0)
- q = (NAN+NAN*I) / zero;
- printf("\tTest{complex(%s, %s), complex(%s, %s), complex(%s, %s)},\n",
+ printf("\t{complex(%s, %s), complex(%s, %s), complex(%s, %s)},\n",
fmt(creal(n)), fmt(cimag(n)),
fmt(creal(d)), fmt(cimag(d)),
fmt(creal(q)), fmt(cimag(q)));
