[msan] Fix wordexp after D108646

I introduced this bug reformating the patch before commit.

Author: vitalybuka

compiler-rt/lib/msan/tests/msan_test.cpp

@@ -3758,6 +3758,7 @@ TEST(MemorySanitizer, wordexp) {
   ASSERT_STREQ("a", w.we_wordv[0]);
   ASSERT_STREQ("b", w.we_wordv[1]);
   ASSERT_STREQ("c", w.we_wordv[2]);
+  EXPECT_POISONED(w.we_wordv[3]);
 }
 
 TEST(MemorySanitizer, wordexp_initial_offset) {
@@ -3770,6 +3771,7 @@ TEST(MemorySanitizer, wordexp_initial_offset) {
   ASSERT_STREQ("a", w.we_wordv[1]);
   ASSERT_STREQ("b", w.we_wordv[2]);
   ASSERT_STREQ("c", w.we_wordv[3]);
+  EXPECT_POISONED(w.we_wordv[4]);
 }
 
 template<class T>

compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc

@@ -3997,7 +3997,7 @@ INTERCEPTOR(int, wordexp, char *s, __sanitizer_wordexp_t *p, int flags) {
   if (!res && p) {
     COMMON_INTERCEPTOR_WRITE_RANGE(ctx, p, sizeof(*p));
     uptr we_wordc =
-        ((flags & wordexp_wrde_dooffs) ? p->we_wordc : 0) + p->we_wordc;
+        ((flags & wordexp_wrde_dooffs) ? p->we_offs : 0) + p->we_wordc;
     if (we_wordc)
       COMMON_INTERCEPTOR_WRITE_RANGE(ctx, p->we_wordv,
                                      sizeof(*p->we_wordv) * we_wordc);