Update upstream source from tag 'upstream/1.52.1+dfsg1'

[rustc.git] / vendor / bytecount / src / simd / x86_sse2.rs

diff --git a/vendor/bytecount/src/simd/x86_sse2.rs b/vendor/bytecount/src/simd/x86_sse2.rs
new file mode 100644 (file)
index 0000000..63d295e
--- /dev/null
+++ b/vendor/bytecount/src/simd/x86_sse2.rs
@@ -0,0 +1,171 @@
+#[cfg(target_arch = "x86")]
+use std::arch::x86::{
+    __m128i,
+    _mm_and_si128,
+    _mm_cmpeq_epi8,
+    _mm_extract_epi32,
+    _mm_loadu_si128,
+    _mm_sad_epu8,
+    _mm_set1_epi8,
+    _mm_setzero_si128,
+    _mm_sub_epi8,
+    _mm_xor_si128,
+};
+
+#[cfg(target_arch = "x86_64")]
+use std::arch::x86_64::{
+    __m128i,
+    _mm_and_si128,
+    _mm_cmpeq_epi8,
+    _mm_extract_epi32,
+    _mm_loadu_si128,
+    _mm_sad_epu8,
+    _mm_set1_epi8,
+    _mm_setzero_si128,
+    _mm_sub_epi8,
+    _mm_xor_si128,
+};
+
+#[target_feature(enable = "sse2")]
+pub unsafe fn _mm_set1_epu8(a: u8) -> __m128i {
+    _mm_set1_epi8(a as i8)
+}
+
+#[target_feature(enable = "sse2")]
+pub unsafe fn mm_cmpneq_epi8(a: __m128i, b: __m128i) -> __m128i {
+    _mm_xor_si128(_mm_cmpeq_epi8(a, b), _mm_set1_epi8(-1))
+}
+
+const MASK: [u8; 32] = [
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+];
+
+#[target_feature(enable = "sse2")]
+unsafe fn mm_from_offset(slice: &[u8], offset: usize) -> __m128i {
+    _mm_loadu_si128(slice.as_ptr().offset(offset as isize) as *const _)
+}
+
+#[target_feature(enable = "sse2")]
+unsafe fn sum(u8s: &__m128i) -> usize {
+    let sums = _mm_sad_epu8(*u8s, _mm_setzero_si128());
+    (_mm_extract_epi32(sums, 0) + _mm_extract_epi32(sums, 2)) as usize
+}
+
+#[target_feature(enable = "sse2")]
+pub unsafe fn chunk_count(haystack: &[u8], needle: u8) -> usize {
+    assert!(haystack.len() >= 16);
+
+    let mut offset = 0;
+    let mut count = 0;
+
+    let needles = _mm_set1_epu8(needle);
+
+    // 4080
+    while haystack.len() >= offset + 16 * 255 {
+        let mut counts = _mm_setzero_si128();
+        for _ in 0..255 {
+            counts = _mm_sub_epi8(
+                counts,
+                _mm_cmpeq_epi8(mm_from_offset(haystack, offset), needles)
+            );
+            offset += 16;
+        }
+        count += sum(&counts);
+    }
+
+    // 2048
+    if haystack.len() >= offset + 16 * 128 {
+        let mut counts = _mm_setzero_si128();
+        for _ in 0..128 {
+            counts = _mm_sub_epi8(
+                counts,
+                _mm_cmpeq_epi8(mm_from_offset(haystack, offset), needles)
+            );
+            offset += 16;
+        }
+        count += sum(&counts);
+    }
+
+    // 16
+    let mut counts = _mm_setzero_si128();
+    for i in 0..(haystack.len() - offset) / 16 {
+        counts = _mm_sub_epi8(
+            counts,
+            _mm_cmpeq_epi8(mm_from_offset(haystack, offset + i * 16), needles)
+        );
+    }
+    if haystack.len() % 16 != 0 {
+        counts = _mm_sub_epi8(
+            counts,
+            _mm_and_si128(
+                _mm_cmpeq_epi8(mm_from_offset(haystack, haystack.len() - 16), needles),
+                                  mm_from_offset(&MASK, haystack.len() % 16)
+            )
+        );
+    }
+    count += sum(&counts);
+
+    count
+}
+
+#[target_feature(enable = "sse2")]
+unsafe fn is_leading_utf8_byte(u8s: __m128i) -> __m128i {
+    mm_cmpneq_epi8(_mm_and_si128(u8s, _mm_set1_epu8(0b1100_0000)), _mm_set1_epu8(0b1000_0000))
+}
+
+#[target_feature(enable = "sse2")]
+pub unsafe fn chunk_num_chars(utf8_chars: &[u8]) -> usize {
+    assert!(utf8_chars.len() >= 16);
+
+    let mut offset = 0;
+    let mut count = 0;
+
+    // 4080
+    while utf8_chars.len() >= offset + 16 * 255 {
+        let mut counts = _mm_setzero_si128();
+
+        for _ in 0..255 {
+            counts = _mm_sub_epi8(
+                counts,
+                is_leading_utf8_byte(mm_from_offset(utf8_chars, offset))
+            );
+            offset += 16;
+        }
+        count += sum(&counts);
+    }
+
+    // 2048
+    if utf8_chars.len() >= offset + 16 * 128 {
+        let mut counts = _mm_setzero_si128();
+        for _ in 0..128 {
+            counts = _mm_sub_epi8(
+                counts,
+                is_leading_utf8_byte(mm_from_offset(utf8_chars, offset))
+            );
+            offset += 16;
+        }
+        count += sum(&counts);
+    }
+
+    // 16
+    let mut counts = _mm_setzero_si128();
+    for i in 0..(utf8_chars.len() - offset) / 16 {
+        counts = _mm_sub_epi8(
+            counts,
+            is_leading_utf8_byte(mm_from_offset(utf8_chars, offset + i * 16))
+        );
+    }
+    if utf8_chars.len() % 16 != 0 {
+        counts = _mm_sub_epi8(
+            counts,
+            _mm_and_si128(
+                is_leading_utf8_byte(mm_from_offset(utf8_chars, utf8_chars.len() - 16)),
+                                     mm_from_offset(&MASK,      utf8_chars.len() % 16)
+            )
+        );
+    }
+    count += sum(&counts);
+
+    count
+}