[LEB128] Mark error condition with LLVM_UNLIKELY

Author: adrian-prantl

llvm/include/llvm/Support/LEB128.h

@@ -135,15 +135,16 @@ inline uint64_t decodeULEB128(const uint8_t *p, unsigned *n = nullptr,
   uint64_t Value = 0;
   unsigned Shift = 0;
   do {
-    if (p == end) {
+    if (LLVM_UNLIKELY(p == end)) {
       if (error)
         *error = "malformed uleb128, extends past end";
       Value = 0;
       break;
     }
     uint64_t Slice = *p & 0x7f;
-    if (Shift >= 63 && ((Shift == 63 && (Slice << Shift >> Shift) != Slice) ||
-                        (Shift > 63 && Slice != 0))) {
+    if (LLVM_UNLIKELY(Shift >= 63) &&
+        ((Shift == 63 && (Slice << Shift >> Shift) != Slice) ||
+         (Shift > 63 && Slice != 0))) {
       if (error)
         *error = "uleb128 too big for uint64";
       Value = 0;
@@ -169,7 +170,7 @@ inline int64_t decodeSLEB128(const uint8_t *p, unsigned *n = nullptr,
   unsigned Shift = 0;
   uint8_t Byte;
   do {
-    if (p == end) {
+    if (LLVM_UNLIKELY(p == end)) {
       if (error)
         *error = "malformed sleb128, extends past end";
       if (n)
@@ -178,8 +179,9 @@ inline int64_t decodeSLEB128(const uint8_t *p, unsigned *n = nullptr,
     }
     Byte = *p;
     uint64_t Slice = Byte & 0x7f;
-    if ((Shift >= 63) && ((Shift == 63 && Slice != 0 && Slice != 0x7f) ||
-                          (Shift > 63 && Slice != (Value < 0 ? 0x7f : 0x00)))) {
+    if (LLVM_UNLIKELY(Shift >= 63) &&
+        ((Shift == 63 && Slice != 0 && Slice != 0x7f) ||
+         (Shift > 63 && Slice != (Value < 0 ? 0x7f : 0x00)))) {
       if (error)
         *error = "sleb128 too big for int64";
       if (n)