lib/glibc
1
0
Fork 0
mirror of https://sourceware.org/git/glibc.git synced 2026-10-24 01:33:52 +03:00
Code Activity

math: Fix potential underflow on ldbl-128 erfl

Browse Source 
The multiplication is only required if the branch is taken, and the
compiler might not optimize it away.

If fixes the following issues when testcase is built with clang:

FAIL: math/test-ldouble-erf
Failure: erf (-0x4p-16384): Exception "Underflow" set
Failure: erf (0x1p-10000): Exception "Underflow" set
Failure: erf (0x3.8b7f12369ded54f38760a41abb84p-16384): Exception "Underflow" set
Failure: erf (0x3.8b7f12369ded54f38760a41abb88p-16384): Exception "Underflow" set
Failure: erf (0x3.8b7f12369ded54f4p-16384): Exception "Underflow" set
Failure: erf (0x3.8b7f12369ded54f8p-16384): Exception "Underflow" set
Failure: erf (0x3.8b7f12369ded5518p-16384): Exception "Underflow" set
Failure: erf (0x3.8b7f12369ded551cp-16384): Exception "Underflow" set
Failure: erf (0x3.8b7f12369ded552p-16384): Exception "Underflow" set
Failure: erf (0x4p-16384): Exception "Underflow" set
Failure: erf_downward (-0x4p-16384): Exception "Underflow" set
Failure: erf_downward (0x1p-10000): Exception "Underflow" set
Failure: erf_downward (0x3.8b7f12369ded54f38760a41abb84p-16384): Exception "Underflow" set
Failure: erf_downward (0x3.8b7f12369ded54f38760a41abb88p-16384): Exception "Underflow" set
Failure: erf_downward (0x3.8b7f12369ded54f4p-16384): Exception "Underflow" set
Failure: erf_downward (0x3.8b7f12369ded54f8p-16384): Exception "Underflow" set
Failure: erf_downward (0x3.8b7f12369ded5518p-16384): Exception "Underflow" set
Failure: erf_downward (0x3.8b7f12369ded551cp-16384): Exception "Underflow" set
Failure: erf_downward (0x3.8b7f12369ded552p-16384): Exception "Underflow" set
Failure: erf_downward (0x4p-16384): Exception "Underflow" set
Failure: erf_towardzero (-0x4p-16384): Exception "Underflow" set
Failure: erf_towardzero (0x1p-10000): Exception "Underflow" set
Failure: erf_towardzero (0x3.8b7f12369ded54f38760a41abb84p-16384): Exception "Underflow" set
Failure: erf_towardzero (0x3.8b7f12369ded54f38760a41abb88p-16384): Exception "Underflow" set
Failure: erf_towardzero (0x3.8b7f12369ded54f4p-16384): Exception "Underflow" set
Failure: erf_towardzero (0x3.8b7f12369ded54f8p-16384): Exception "Underflow" set
Failure: erf_towardzero (0x3.8b7f12369ded5518p-16384): Exception "Underflow" set
Failure: erf_towardzero (0x3.8b7f12369ded551cp-16384): Exception "Underflow" set
Failure: erf_towardzero (0x3.8b7f12369ded552p-16384): Exception "Underflow" set
Failure: erf_towardzero (0x4p-16384): Exception "Underflow" set
Failure: erf_upward (-0x4p-16384): Exception "Underflow" set
Failure: erf_upward (0x1p-10000): Exception "Underflow" set
Failure: erf_upward (0x3.8b7f12369ded54f38760a41abb84p-16384): Exception "Underflow" set
Failure: erf_upward (0x3.8b7f12369ded54f38760a41abb88p-16384): Exception "Underflow" set
Failure: erf_upward (0x3.8b7f12369ded54f4p-16384): Exception "Underflow" set
Failure: erf_upward (0x3.8b7f12369ded54f8p-16384): Exception "Underflow" set
Failure: erf_upward (0x3.8b7f12369ded5518p-16384): Exception "Underflow" set
Failure: erf_upward (0x3.8b7f12369ded551cp-16384): Exception "Underflow" set
Failure: erf_upward (0x3.8b7f12369ded552p-16384): Exception "Underflow" set
Failure: erf_upward (0x4p-16384): Exception "Underflow" set

Checked on aarch64-linux-gnu with gcc and clang.
This commit is contained in:
Adhemerval Zanella
2024-01-30 13:45:14 +00:00
parent 8cfd63d0af
commit 9eb3cb13da
1 changed files with 1 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
sysdeps/ieee754/ldbl-128/s_erfl.c
View File

@@ -778,7 +778,6 @@ __erfl (_Float128 x)
}
u.parts32.w0 = ix;
a = u.value;
z = x * x;
if (ix < 0x3ffec000) /* a < 0.875 */
{
if (ix < 0x3fc60000) /* |x|<2**-57 */
@@ -792,6 +791,7 @@ __erfl (_Float128 x)
}
return x + efx * x;
}
z = x * x;
y = a + a * neval (z, TN1, NTN1) / deval (z, TD1, NTD1);
}
else