From 51e9430a0c000bc8b4710487e9b72d41842d53a6 Mon Sep 17 00:00:00 2001
From: DongHun Kwak <dh0128.kwak@samsung.com>
Date: Wed, 23 Sep 2020 15:45:47 +0900
Subject: [PATCH] Imported Upstream version 20200801

---
 re2/prefilter.cc |  5 +++--
 re2/simplify.cc  | 14 +++++++++++---
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/re2/prefilter.cc b/re2/prefilter.cc
index f61d54b..a47b312 100644
--- a/re2/prefilter.cc
+++ b/re2/prefilter.cc
@@ -648,14 +648,15 @@ Prefilter* Prefilter::FromRegexp(Regexp* re) {
     return NULL;
 
   Regexp* simple = re->Simplify();
-  Prefilter::Info *info = BuildInfo(simple);
+  if (simple == NULL)
+    return NULL;
 
+  Prefilter::Info* info = BuildInfo(simple);
   simple->Decref();
   if (info == NULL)
     return NULL;
 
   Prefilter* m = info->TakeMatch();
-
   delete info;
   return m;
 }
diff --git a/re2/simplify.cc b/re2/simplify.cc
index 270f0ff..663d5fc 100644
--- a/re2/simplify.cc
+++ b/re2/simplify.cc
@@ -28,8 +28,6 @@ bool Regexp::SimplifyRegexp(const StringPiece& src, ParseFlags flags,
   Regexp* sre = re->Simplify();
   re->Decref();
   if (sre == NULL) {
-    // Should not happen, since Simplify never fails.
-    LOG(ERROR) << "Simplify failed on " << src;
     if (status) {
       status->set_code(kRegexpInternalError);
       status->set_error_arg(src);
@@ -180,10 +178,20 @@ Regexp* Regexp::Simplify() {
   CoalesceWalker cw;
   Regexp* cre = cw.Walk(this, NULL);
   if (cre == NULL)
-    return cre;
+    return NULL;
+  if (cw.stopped_early()) {
+    cre->Decref();
+    return NULL;
+  }
   SimplifyWalker sw;
   Regexp* sre = sw.Walk(cre, NULL);
   cre->Decref();
+  if (sre == NULL)
+    return NULL;
+  if (sw.stopped_early()) {
+    sre->Decref();
+    return NULL;
+  }
   return sre;
 }
 
-- 
2.7.4