Index: include/llvm/Support/SHA1.h
===================================================================
--- include/llvm/Support/SHA1.h
+++ include/llvm/Support/SHA1.h
@@ -61,7 +61,10 @@
 
   // Internal State
   struct {
-    uint32_t Buffer[BLOCK_LENGTH / 4];
+    union {
+      uint8_t C[BLOCK_LENGTH];
+      uint32_t L[BLOCK_LENGTH / 4];
+    } Buffer;
     uint32_t State[HASH_LENGTH / 4];
     uint32_t ByteCount;
     uint8_t BufferOffset;
Index: lib/Support/SHA1.cpp
===================================================================
--- lib/Support/SHA1.cpp
+++ lib/Support/SHA1.cpp
@@ -6,8 +6,10 @@
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
+//
 // This code is taken from public domain
-// (http://oauth.googlecode.com/svn/code/c/liboauth/src/sha1.c)
+// (http://oauth.googlecode.com/svn/code/c/liboauth/src/sha1.c and
+// http://cvsweb.netbsd.org/bsdweb.cgi/src/common/lib/libc/hash/sha1/sha1.c?rev=1.6)
 // and modified by wrapping it in a C++ interface for LLVM,
 // and removing unnecessary code.
 //
@@ -25,6 +27,56 @@
 #define SHA_BIG_ENDIAN
 #endif
 
+static uint32_t rol(uint32_t number, int bits) {
+  return (number << bits) | (number >> (32 - bits));
+};
+
+#if SHA_BIG_ENDIAN
+static uint32_t blk0(uint32_t *Buf, int I) {
+  Buf[I] = (rol(Buf[I], 24) & 0xFF00FF00) | (rol(Buf[I], 8) & 0x00FF00FF);
+  return Buf[I];
+}
+#else
+static uint32_t blk0(uint32_t *Buf, int I) { return Buf[I]; }
+#endif
+
+static uint32_t blk(uint32_t *Buf, int I) {
+  Buf[I & 15] = rol(Buf[(I + 13) & 15] ^ Buf[(I + 8) & 15] ^ Buf[(I + 2) & 15] ^
+                        Buf[I & 15],
+                    1);
+  return Buf[I & 15];
+}
+
+static void r0(uint32_t &A, uint32_t &B, uint32_t &C, uint32_t &D, uint32_t &E,
+               int I, uint32_t *Buf) {
+  E += ((B & (C ^ D)) ^ D) + blk0(Buf, I) + 0x5A827999 + rol(A, 5);
+  B = rol(B, 30);
+}
+
+static void r1(uint32_t &A, uint32_t &B, uint32_t &C, uint32_t &D, uint32_t &E,
+               int I, uint32_t *Buf) {
+  E += ((B & (C ^ D)) ^ D) + blk(Buf, I) + 0x5A827999 + rol(A, 5);
+  B = rol(B, 30);
+}
+
+static void r2(uint32_t &A, uint32_t &B, uint32_t &C, uint32_t &D, uint32_t &E,
+               int I, uint32_t *Buf) {
+  E += (B ^ C ^ D) + blk(Buf, I) + 0x6ED9EBA1 + rol(A, 5);
+  B = rol(B, 30);
+}
+
+static void r3(uint32_t &A, uint32_t &B, uint32_t &C, uint32_t &D, uint32_t &E,
+               int I, uint32_t *Buf) {
+  E += (((B | C) & D) | (B & C)) + blk(Buf, I) + 0x8F1BBCDC + rol(A, 5);
+  B = rol(B, 30);
+}
+
+static void r4(uint32_t &A, uint32_t &B, uint32_t &C, uint32_t &D, uint32_t &E,
+               int I, uint32_t *Buf) {
+  E += (B ^ C ^ D) + blk(Buf, I) + 0xCA62C1D6 + rol(A, 5);
+  B = rol(B, 30);
+}
+
 /* code */
 #define SHA1_K0 0x5a827999
 #define SHA1_K20 0x6ed9eba1
@@ -47,56 +99,112 @@
   InternalState.BufferOffset = 0;
 }
 
-static uint32_t rol32(uint32_t number, uint8_t bits) {
-  return ((number << bits) | (number >> (32 - bits)));
-}
-
 void SHA1::hashBlock() {
-  uint8_t i;
-  uint32_t a, b, c, d, e, t;
-
-  a = InternalState.State[0];
-  b = InternalState.State[1];
-  c = InternalState.State[2];
-  d = InternalState.State[3];
-  e = InternalState.State[4];
-  for (i = 0; i < 80; i++) {
-    if (i >= 16) {
-      t = InternalState.Buffer[(i + 13) & 15] ^
-          InternalState.Buffer[(i + 8) & 15] ^
-          InternalState.Buffer[(i + 2) & 15] ^ InternalState.Buffer[i & 15];
-      InternalState.Buffer[i & 15] = rol32(t, 1);
-    }
-    if (i < 20) {
-      t = (d ^ (b & (c ^ d))) + SHA1_K0;
-    } else if (i < 40) {
-      t = (b ^ c ^ d) + SHA1_K20;
-    } else if (i < 60) {
-      t = ((b & c) | (d & (b | c))) + SHA1_K40;
-    } else {
-      t = (b ^ c ^ d) + SHA1_K60;
-    }
-    t += rol32(a, 5) + e + InternalState.Buffer[i & 15];
-    e = d;
-    d = c;
-    c = rol32(b, 30);
-    b = a;
-    a = t;
-  }
-  InternalState.State[0] += a;
-  InternalState.State[1] += b;
-  InternalState.State[2] += c;
-  InternalState.State[3] += d;
-  InternalState.State[4] += e;
+  uint32_t A = InternalState.State[0];
+  uint32_t B = InternalState.State[1];
+  uint32_t C = InternalState.State[2];
+  uint32_t D = InternalState.State[3];
+  uint32_t E = InternalState.State[4];
+
+  // 4 rounds of 20 operations each. Loop unrolled.
+  r0(A, B, C, D, E, 0, InternalState.Buffer.L);
+  r0(E, A, B, C, D, 1, InternalState.Buffer.L);
+  r0(D, E, A, B, C, 2, InternalState.Buffer.L);
+  r0(C, D, E, A, B, 3, InternalState.Buffer.L);
+  r0(B, C, D, E, A, 4, InternalState.Buffer.L);
+  r0(A, B, C, D, E, 5, InternalState.Buffer.L);
+  r0(E, A, B, C, D, 6, InternalState.Buffer.L);
+  r0(D, E, A, B, C, 7, InternalState.Buffer.L);
+  r0(C, D, E, A, B, 8, InternalState.Buffer.L);
+  r0(B, C, D, E, A, 9, InternalState.Buffer.L);
+  r0(A, B, C, D, E, 10, InternalState.Buffer.L);
+  r0(E, A, B, C, D, 11, InternalState.Buffer.L);
+  r0(D, E, A, B, C, 12, InternalState.Buffer.L);
+  r0(C, D, E, A, B, 13, InternalState.Buffer.L);
+  r0(B, C, D, E, A, 14, InternalState.Buffer.L);
+  r0(A, B, C, D, E, 15, InternalState.Buffer.L);
+  r1(E, A, B, C, D, 16, InternalState.Buffer.L);
+  r1(D, E, A, B, C, 17, InternalState.Buffer.L);
+  r1(C, D, E, A, B, 18, InternalState.Buffer.L);
+  r1(B, C, D, E, A, 19, InternalState.Buffer.L);
+
+  r2(A, B, C, D, E, 20, InternalState.Buffer.L);
+  r2(E, A, B, C, D, 21, InternalState.Buffer.L);
+  r2(D, E, A, B, C, 22, InternalState.Buffer.L);
+  r2(C, D, E, A, B, 23, InternalState.Buffer.L);
+  r2(B, C, D, E, A, 24, InternalState.Buffer.L);
+  r2(A, B, C, D, E, 25, InternalState.Buffer.L);
+  r2(E, A, B, C, D, 26, InternalState.Buffer.L);
+  r2(D, E, A, B, C, 27, InternalState.Buffer.L);
+  r2(C, D, E, A, B, 28, InternalState.Buffer.L);
+  r2(B, C, D, E, A, 29, InternalState.Buffer.L);
+  r2(A, B, C, D, E, 30, InternalState.Buffer.L);
+  r2(E, A, B, C, D, 31, InternalState.Buffer.L);
+  r2(D, E, A, B, C, 32, InternalState.Buffer.L);
+  r2(C, D, E, A, B, 33, InternalState.Buffer.L);
+  r2(B, C, D, E, A, 34, InternalState.Buffer.L);
+  r2(A, B, C, D, E, 35, InternalState.Buffer.L);
+  r2(E, A, B, C, D, 36, InternalState.Buffer.L);
+  r2(D, E, A, B, C, 37, InternalState.Buffer.L);
+  r2(C, D, E, A, B, 38, InternalState.Buffer.L);
+  r2(B, C, D, E, A, 39, InternalState.Buffer.L);
+
+  r3(A, B, C, D, E, 40, InternalState.Buffer.L);
+  r3(E, A, B, C, D, 41, InternalState.Buffer.L);
+  r3(D, E, A, B, C, 42, InternalState.Buffer.L);
+  r3(C, D, E, A, B, 43, InternalState.Buffer.L);
+  r3(B, C, D, E, A, 44, InternalState.Buffer.L);
+  r3(A, B, C, D, E, 45, InternalState.Buffer.L);
+  r3(E, A, B, C, D, 46, InternalState.Buffer.L);
+  r3(D, E, A, B, C, 47, InternalState.Buffer.L);
+  r3(C, D, E, A, B, 48, InternalState.Buffer.L);
+  r3(B, C, D, E, A, 49, InternalState.Buffer.L);
+  r3(A, B, C, D, E, 50, InternalState.Buffer.L);
+  r3(E, A, B, C, D, 51, InternalState.Buffer.L);
+  r3(D, E, A, B, C, 52, InternalState.Buffer.L);
+  r3(C, D, E, A, B, 53, InternalState.Buffer.L);
+  r3(B, C, D, E, A, 54, InternalState.Buffer.L);
+  r3(A, B, C, D, E, 55, InternalState.Buffer.L);
+  r3(E, A, B, C, D, 56, InternalState.Buffer.L);
+  r3(D, E, A, B, C, 57, InternalState.Buffer.L);
+  r3(C, D, E, A, B, 58, InternalState.Buffer.L);
+  r3(B, C, D, E, A, 59, InternalState.Buffer.L);
+
+  r4(A, B, C, D, E, 60, InternalState.Buffer.L);
+  r4(E, A, B, C, D, 61, InternalState.Buffer.L);
+  r4(D, E, A, B, C, 62, InternalState.Buffer.L);
+  r4(C, D, E, A, B, 63, InternalState.Buffer.L);
+  r4(B, C, D, E, A, 64, InternalState.Buffer.L);
+  r4(A, B, C, D, E, 65, InternalState.Buffer.L);
+  r4(E, A, B, C, D, 66, InternalState.Buffer.L);
+  r4(D, E, A, B, C, 67, InternalState.Buffer.L);
+  r4(C, D, E, A, B, 68, InternalState.Buffer.L);
+  r4(B, C, D, E, A, 69, InternalState.Buffer.L);
+  r4(A, B, C, D, E, 70, InternalState.Buffer.L);
+  r4(E, A, B, C, D, 71, InternalState.Buffer.L);
+  r4(D, E, A, B, C, 72, InternalState.Buffer.L);
+  r4(C, D, E, A, B, 73, InternalState.Buffer.L);
+  r4(B, C, D, E, A, 74, InternalState.Buffer.L);
+  r4(A, B, C, D, E, 75, InternalState.Buffer.L);
+  r4(E, A, B, C, D, 76, InternalState.Buffer.L);
+  r4(D, E, A, B, C, 77, InternalState.Buffer.L);
+  r4(C, D, E, A, B, 78, InternalState.Buffer.L);
+  r4(B, C, D, E, A, 79, InternalState.Buffer.L);
+
+  InternalState.State[0] += A;
+  InternalState.State[1] += B;
+  InternalState.State[2] += C;
+  InternalState.State[3] += D;
+  InternalState.State[4] += E;
 }
 
 void SHA1::addUncounted(uint8_t data) {
-  uint8_t *const b = (uint8_t *)InternalState.Buffer;
 #ifdef SHA_BIG_ENDIAN
-  b[InternalState.BufferOffset] = data;
+  InternalState.Buffer.C[InternalState.BufferOffset] = data;
 #else
-  b[InternalState.BufferOffset ^ 3] = data;
+  InternalState.Buffer.C[InternalState.BufferOffset ^ 3] = data;
 #endif
+
   InternalState.BufferOffset++;
   if (InternalState.BufferOffset == BLOCK_LENGTH) {
     hashBlock();