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| author | Kostya Serebryany <kcc@google.com> | 2018-09-04 22:43:30 +0000 |
|---|---|---|
| committer | Kostya Serebryany <kcc@google.com> | 2018-09-04 22:43:30 +0000 |
| commit | 380632208bda2cf9900f48a1cbdca5b2b6805ca9 (patch) | |
| tree | 36a35da78cba2425f9d4218b729b0b4984e6fb47 | |
| parent | f2f515f8190982a79e895bb9fc7d0ab25d68cee8 (diff) | |
| download | compiler-rt-380632208bda2cf9900f48a1cbdca5b2b6805ca9.tar.gz | |
[sanitizer] optimize internal_memset for the most performance critical case (16-byte-aligned)
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@341420 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/sanitizer_common/sanitizer_libc.cc | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/lib/sanitizer_common/sanitizer_libc.cc b/lib/sanitizer_common/sanitizer_libc.cc index 4b462bfe9..4032cb104 100644 --- a/lib/sanitizer_common/sanitizer_libc.cc +++ b/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 |