diff --git a/CHANGES b/CHANGES
index 7b9b1a1c40..b97ef5be88 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,4 +1,8 @@
 
+3.1.0-dev.357 | 2020-01-06 14:10:54 -0800
+
+  * GH-412: Enable Patterns as Table index (Dev Bali, Corelight)
+
 3.1.0-dev.354 | 2020-01-06 14:16:29 -0700
 
   * Fix snprintf compiler warning in hexdump BIF (Jon Siwek, Corelight)
diff --git a/VERSION b/VERSION
index f2cd0981c7..b97d001f0b 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-3.1.0-dev.354
+3.1.0-dev.357
diff --git a/src/CompHash.cc b/src/CompHash.cc
index 327778c5c5..107eeefde8 100644
--- a/src/CompHash.cc
+++ b/src/CompHash.cc
@@ -146,6 +146,30 @@ char* CompositeHash::SingleValHash(int type_check, char* kp0,
 			break;
 			}
 
+		case TYPE_PATTERN:
+			{
+			const char* texts[2] = {
+				v->AsPattern()->PatternText(),
+				v->AsPattern()->AnywherePatternText()
+			};
+
+			size_t* kp;
+			for ( int i = 0; i < 2; i++ )
+				{
+				kp = AlignAndPadType<size_t>(kp0+i);
+				*kp = strlen(texts[i]) + 1;
+				}
+
+			kp1 = reinterpret_cast<char*>(kp+1);
+			for ( int i = 0; i < 2; i++ )
+				{
+				memcpy(kp1, texts[i], strlen(texts[i]) + 1);
+				kp1 += strlen(texts[i]) + 1;
+				}
+
+			break;
+			}
+
 		case TYPE_RECORD:
 			{
 			char* kp = kp0;
@@ -401,6 +425,19 @@ HashKey* CompositeHash::ComputeSingletonHash(const Val* v, int type_check) const
 		if ( v->Type()->Tag() == TYPE_FUNC )
 			return new HashKey(v->AsFunc()->GetUniqueFuncID());
 
+		if ( v->Type()->Tag() == TYPE_PATTERN )
+			{
+			const char* texts[2] = {
+				v->AsPattern()->PatternText(),
+				v->AsPattern()->AnywherePatternText()
+			};
+			int n = strlen(texts[0]) + strlen(texts[1]) + 2; // 2 for null
+			char* key = new char[n];
+			std::memcpy(key, texts[0], strlen(texts[0]) + 1);
+			std::memcpy(key + strlen(texts[0]) + 1, texts[1], strlen(texts[1]) + 1);
+			return new HashKey(false, key, n);
+			}
+
 		reporter->InternalError("bad index type in CompositeHash::ComputeSingletonHash");
 		return 0;
 
@@ -462,6 +499,17 @@ int CompositeHash::SingleTypeKeySize(BroType* bt, const Val* v,
 			break;
 			}
 
+		case TYPE_PATTERN:
+			{
+			if ( ! v )
+				return (optional && ! calc_static_size) ? sz : 0;
+
+			sz = SizeAlign(sz, 2 * sizeof(size_t));
+			sz += strlen(v->AsPattern()->PatternText())
+				+ strlen(v->AsPattern()->AnywherePatternText()) + 2; // 2 for null terminators
+			break;
+			}
+
 		case TYPE_RECORD:
 			{
 			const RecordVal* rv = v ? v->AsRecordVal() : 0;
@@ -831,6 +879,28 @@ const char* CompositeHash::RecoverOneVal(const HashKey* k, const char* kp0,
 			}
 			break;
 
+		case TYPE_PATTERN:
+			{
+			RE_Matcher* re = nullptr;
+			if ( is_singleton )
+				{
+				kp1 = kp0;
+				int divider = strlen(kp0) + 1;
+				re = new RE_Matcher(kp1, kp1 + divider);
+				kp1 += k->Size();
+				}
+			else
+				{
+				const size_t* const len = AlignType<size_t>(kp0);
+
+				kp1 = reinterpret_cast<const char*>(len+2);
+				re = new RE_Matcher(kp1, kp1 + len[0]);
+				kp1 += len[0] + len[1];
+				}
+			pval = new PatternVal(re);
+			}
+			break;
+
 		case TYPE_RECORD:
 			{
 			const char* kp = kp0;
diff --git a/src/Type.cc b/src/Type.cc
index c3e12f5a29..43f5da6267 100644
--- a/src/Type.cc
+++ b/src/Type.cc
@@ -391,7 +391,7 @@ TableType::TableType(TypeList* ind, BroType* yield)
 		// Allow functions, since they can be compared
 		// for Func* pointer equality.
 		if ( t == TYPE_INTERNAL_OTHER && tli->Tag() != TYPE_FUNC &&
-		     tli->Tag() != TYPE_RECORD )
+		     tli->Tag() != TYPE_RECORD && tli->Tag() != TYPE_PATTERN )
 			{
 			tli->Error("bad index type");
 			SetError();
diff --git a/testing/btest/Baseline/language.table-pattern-index/out b/testing/btest/Baseline/language.table-pattern-index/out
new file mode 100644
index 0000000000..823acad741
--- /dev/null
+++ b/testing/btest/Baseline/language.table-pattern-index/out
@@ -0,0 +1,19 @@
+/^?(one|foo|bar)$?/
+/^?(two|oob)$?/
+/^?(three|oob)$?/
+/^?(four)$?/
+-----------------
+/^?(two|oob)$?/
+/^?(four)$?/
+/^?(one|foo|bar)$?/
+/^?(three|oob)$?/
+-----------------
+/^?(two|oob)$?/, 1
+/^?(four)$?/, 3
+/^?(one|foo|bar)$?/, 0
+/^?(three|oob)$?/, 2
+-----------------
+/^?(two|oob)$?/, 3, 2
+/^?(one|foo|bar)$?/, 2, 0
+/^?(four)$?/, 5, 6
+/^?(three|oob)$?/, 4, 4
diff --git a/testing/btest/language/table-pattern-index.zeek b/testing/btest/language/table-pattern-index.zeek
new file mode 100644
index 0000000000..1b33a8e27a
--- /dev/null
+++ b/testing/btest/language/table-pattern-index.zeek
@@ -0,0 +1,43 @@
+# @TEST-EXEC: zeek -b %INPUT >out
+# @TEST-EXEC: btest-diff out
+
+local p1: pattern = /one|foo|bar/;
+local p2: pattern = /two|oob/;
+local p3: pattern = /three|oob/;
+local p4 = /four/;
+
+local p: set[pattern] = {p1, p2, p3, p4};
+
+local t: table[pattern] of count = {
+	[p1] = 0,
+	[p2] = 1,
+	[p3] = 2,
+	[p4] = 3
+};
+
+local t2: table[pattern, count] of count = {
+	[p1,2] = 0,
+	[p2,3] = 2,
+	[p3,4] = 4,
+	[p4,5] = 6
+};
+
+print p1;
+print p2;
+print p3;
+print p4;
+
+print "-----------------";
+
+for ( key in p )
+	print key;
+
+print "-----------------";
+
+for ( key, value in t )
+	print key, value;
+
+print "-----------------";
+
+for ( [c1, c2], value in t2)
+	print c1, c2, value;
diff --git a/testing/external/commit-hash.zeek-testing b/testing/external/commit-hash.zeek-testing
index 48383d67d4..5c53cb6426 100644
--- a/testing/external/commit-hash.zeek-testing
+++ b/testing/external/commit-hash.zeek-testing
@@ -1 +1 @@
-8be265e13e9ddb2dda704bf1574b1307fc17eea9
+da47ae786562da18910d994b7868530929db6271
diff --git a/testing/external/commit-hash.zeek-testing-private b/testing/external/commit-hash.zeek-testing-private
index 0bcb565e2c..4c0cb92860 100644
--- a/testing/external/commit-hash.zeek-testing-private
+++ b/testing/external/commit-hash.zeek-testing-private
@@ -1 +1 @@
-2f6f3b9211f5f5b04a2ede17835d0a4a523888f1
+931f49917a86a260c69e091c2f66b693e74b33bf