add test for sqrt(-0)

git-svn-id: https://svn.r-project.org/R/trunk@58223 00db46b3-68df-0310-9c12-caf00c1e9a41

tests/iec60559.R

@@ -10,3 +10,9 @@ exp(c(-745:-740, -730, -720, -710:-705))
 
 # And because most libm pow() functions special-case integer powers.
 10^-(324:307-0.01)/10^0.01
+
+# IEC60559 mandates this, but C99/C11 do not.
+# Mingw-w64 did not do so in v 2.0.1
+x <- 0*(-1) # negative zero
+sqrt(x)
+identical(x, sqrt(x))

tests/iec60559.Rout.save

@@ -1,8 +1,8 @@
 
-R Under development (unstable) (2012-01-04 r58050)
+R Under development (unstable) (2012-01-28 r58222)
 Copyright (C) 2012 The R Foundation for Statistical Computing
 ISBN 3-900051-07-0
-Platform: i386-pc-mingw32/i386 (32-bit)
+Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit)
 
 R is free software and comes with ABSOLUTELY NO WARRANTY.
 You are welcome to redistribute it under certain conditions.
@@ -51,3 +51,11 @@ Type 'q()' to quit R.
 [11] 1.000000e-314 1.000000e-313 1.000000e-312 1.000000e-311 1.000000e-310
 [16] 1.000000e-309 1.000000e-308 1.000000e-307
 > 
+> # IEC60559 mandates this, but C99/C11 do not.
+> # Mingw-w64 did not do so in v 2.0.1
+> x <- 0*(-1) # negative zero
+> sqrt(x)
+[1] 0
+> identical(x, sqrt(x))
+[1] TRUE
+>