Index: llvm/include/llvm/Support/GlobPattern.h
===================================================================
--- llvm/include/llvm/Support/GlobPattern.h
+++ llvm/include/llvm/Support/GlobPattern.h
@@ -31,6 +31,16 @@
   static Expected<GlobPattern> create(StringRef Pat);
   bool match(StringRef S) const;
 
+  // Returns true for glob pattern "*". Can be used to avoid expensive
+  // preparation/acquisition of the input for match().
+  bool isTrivialMatchAll() const {
+    if (Prefix && Prefix->empty()) {
+      assert(!Suffix);
+      return true;
+    }
+    return false;
+  }
+
 private:
   bool matchOne(ArrayRef<BitVector> Pat, StringRef S) const;
 
Index: llvm/unittests/Support/GlobPatternTest.cpp
===================================================================
--- llvm/unittests/Support/GlobPatternTest.cpp
+++ llvm/unittests/Support/GlobPatternTest.cpp
@@ -133,4 +133,28 @@
   EXPECT_TRUE((bool)Pat2);
   EXPECT_TRUE(Pat2->match("\xFF"));
 }
+
+TEST_F(GlobPatternTest, IsTrivialMatchAll) {
+  Expected<GlobPattern> Pat1 = GlobPattern::create("*");
+  EXPECT_TRUE((bool)Pat1);
+  EXPECT_TRUE(Pat1->isTrivialMatchAll());
+  Expected<GlobPattern> Pat2 = GlobPattern::create("a*");
+  EXPECT_TRUE((bool)Pat2);
+  EXPECT_FALSE(Pat2->isTrivialMatchAll());
+  Expected<GlobPattern> Pat3 = GlobPattern::create("*a");
+  EXPECT_TRUE((bool)Pat3);
+  EXPECT_FALSE(Pat3->isTrivialMatchAll());
+  Expected<GlobPattern> Pat4 = GlobPattern::create("**");
+  EXPECT_TRUE((bool)Pat4);
+  EXPECT_FALSE(Pat4->isTrivialMatchAll());
+  Expected<GlobPattern> Pat5 = GlobPattern::create("?*");
+  EXPECT_TRUE((bool)Pat5);
+  EXPECT_FALSE(Pat5->isTrivialMatchAll());
+  Expected<GlobPattern> Pat6 = GlobPattern::create("*?");
+  EXPECT_TRUE((bool)Pat6);
+  EXPECT_FALSE(Pat6->isTrivialMatchAll());
+  Expected<GlobPattern> Pat7 = GlobPattern::create("\\*");
+  EXPECT_TRUE((bool)Pat7);
+  EXPECT_FALSE(Pat7->isTrivialMatchAll());
+}
 }