(2012/11/13 19:28), Masanobu SAITOH wrote:
(2012/11/13 19:24), Masanobu SAITOH wrote:(2012/10/01 17:08), Martin Husemann wrote:On Mon, Oct 01, 2012 at 07:45:01AM +0100, David Laight wrote:I don't call that a fix.Neither do I.There is either a bug in gcc (which will affect other code), or bugs in the softfloat code itself - which will appear again later.Yes - my bet is on the former for now.I debugged this. The problem occurs with -O1 -ftree-vrp. The problem doesn't occur with -O2 -fno-tree-vrp. The problem doesn't occur when SOFTFLOAT_BITS=64 (Note that only arm and emips set it with 64) How about COPTS.softfloat.c+=-fno-tree-vrp? The ATF test result in /usr/tests/lib/libm was as follows (netbsd-6): Summary for 20 test programs: 311 passed test cases. 0 failed test cases. <======== Changed from 16 to 0 4 expected failed test cases. 5 skipped test cases.I tried to fix tree-vrp.c but I knew it's little hard for me to fix :-(Shouldn't be too hard to isolate 1 buggy file and work out exactly where it goes wrong. I'd guess a 'strict aliasing' issue....For someone with enough arm asm fu - probably. The differences in the generated asm are "not small" though, and unfortunately I don't have time to look at details right now. Volunteers welcome... Martin
Some people asked me about my analysis and testcase, so I write about it. ceil(-Inf) desn't return -INF on arm. It returns 0. This test is included in tests/lib/libm/t_ceil. In lib/libm/src/s_ceil.c:
double
ceil(double x)
{
(snip)
} else if (jj0>51) {
if(jj0==0x400) return x+x; /* inf or NaN */
else return x; /* x is integral */
x+x calls adddf3 and it returns 0 even if x is -INF.
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SAITOH Masanobu (msaitoh%execsw.org@localhost
msaitoh%netbsd.org@localhost)