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| author | Paul Eggert <eggert@cs.ucla.edu> | 2015-07-21 22:50:29 -0700 |
|---|---|---|
| committer | Paul Eggert <eggert@cs.ucla.edu> | 2015-08-18 10:00:57 -0700 |
| commit | 5542236837c5c41435f8282ec92799f480c36f18 (patch) | |
| tree | 9379c73ad00dc1ffea986464bbf96634f3a7fd5f /string/memrchr.c | |
| parent | 1814df5b02b9c359052c2048a1d2d617b406a17a (diff) | |
| download | glibc-5542236837c5c41435f8282ec92799f480c36f18.zip glibc-5542236837c5c41435f8282ec92799f480c36f18.tar.gz glibc-5542236837c5c41435f8282ec92799f480c36f18.tar.bz2 | |
Port the 0x7efe...feff pattern to GCC 6.
See Steve Ellcey's bug report in:
https://sourceware.org/ml/libc-alpha/2015-07/msg00673.html
* string/memrchr.c (MEMRCHR):
* string/rawmemchr.c (RAWMEMCHR):
* string/strchr.c (strchr):
* string/strchrnul.c (STRCHRNUL):
Rewrite code to avoid issues with signed shift overflow.
Diffstat (limited to 'string/memrchr.c')
| -rw-r--r-- | string/memrchr.c | 11 |
1 files changed, 2 insertions, 9 deletions
diff --git a/string/memrchr.c b/string/memrchr.c index 0c8fd84..86cd5b9 100644 --- a/string/memrchr.c +++ b/string/memrchr.c @@ -96,15 +96,8 @@ MEMRCHR The 1-bits make sure that carries propagate to the next 0-bit. The 0-bits provide holes for carries to fall into. */ - - if (sizeof (longword) != 4 && sizeof (longword) != 8) - abort (); - -#if LONG_MAX <= LONG_MAX_32_BITS - magic_bits = 0x7efefeff; -#else - magic_bits = ((unsigned long int) 0x7efefefe << 32) | 0xfefefeff; -#endif + magic_bits = -1; + magic_bits = magic_bits / 0xff * 0xfe << 1 >> 1 | 1; /* Set up a longword, each of whose bytes is C. */ charmask = c | (c << 8); |