diff options
Diffstat (limited to 'contrib/compiler-rt/lib/sanitizer_common/sanitizer_libc.cc')
| -rw-r--r-- | contrib/compiler-rt/lib/sanitizer_common/sanitizer_libc.cc | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/contrib/compiler-rt/lib/sanitizer_common/sanitizer_libc.cc b/contrib/compiler-rt/lib/sanitizer_common/sanitizer_libc.cc index 4b462bfe9728..4032cb10461f 100644 --- a/contrib/compiler-rt/lib/sanitizer_common/sanitizer_libc.cc +++ b/contrib/compiler-rt/lib/sanitizer_common/sanitizer_libc.cc @@ -73,6 +73,18 @@ void *internal_memmove(void *dest, const void *src, uptr n) { } void *internal_memset(void* s, int c, uptr n) { + // Optimize for the most performance-critical case: + if ((reinterpret_cast<uptr>(s) % 16) == 0 && (n % 16) == 0) { + u64 *p = reinterpret_cast<u64*>(s); + u64 *e = p + n / 8; + u64 v = c; + v |= v << 8; + v |= v << 16; + v |= v << 32; + for (; p < e; p += 2) + p[0] = p[1] = v; + return s; + } // The next line prevents Clang from making a call to memset() instead of the // loop below. // FIXME: building the runtime with -ffreestanding is a better idea. However |