diff --git a/mpact/sim/decoder/BUILD b/mpact/sim/decoder/BUILD
index 71202c7..00eaa42 100644
--- a/mpact/sim/decoder/BUILD
+++ b/mpact/sim/decoder/BUILD
@@ -117,7 +117,6 @@
         ":antlr_parser_wrapper",
         ":decoder_error_listener",
         ":format_name",
-        "//util/regexp/re2",
         "@com_google_absl//absl/base:no_destructor",
         "@com_google_absl//absl/container:btree",
         "@com_google_absl//absl/container:flat_hash_map",
@@ -129,6 +128,7 @@
         "@com_google_absl//absl/status",
         "@com_google_absl//absl/status:statusor",
         "@com_google_absl//absl/strings",
+        "@com_googlesource_code_re2//:re2",
     ],
 )
 
@@ -221,7 +221,6 @@
         ":bin_format_lexer",
         ":bin_format_parser",
         ":decoder_error_listener",
-        "//util/regexp/re2",
         "@com_google_absl//absl/container:btree",
         "@com_google_absl//absl/container:flat_hash_map",
         "@com_google_absl//absl/container:flat_hash_set",
@@ -231,6 +230,7 @@
         "@com_google_absl//absl/status",
         "@com_google_absl//absl/status:statusor",
         "@com_google_absl//absl/strings",
+        "@com_googlesource_code_re2//:re2",
     ],
 )
 
@@ -319,7 +319,6 @@
         ":proto_format_lexer",
         ":proto_format_parser",
         "//mpact/sim/generic:type_helpers",
-        "//util/regexp/re2",
         "@com_google_absl//absl/container:btree",
         "@com_google_absl//absl/container:flat_hash_map",
         "@com_google_absl//absl/container:flat_hash_set",
@@ -330,6 +329,7 @@
         "@com_google_absl//absl/status:statusor",
         "@com_google_absl//absl/strings",
         "@com_google_protobuf//:protobuf",
+        "@com_googlesource_code_re2//:re2",
     ],
 )
 
diff --git a/mpact/sim/decoder/bin_format_visitor.cc b/mpact/sim/decoder/bin_format_visitor.cc
index 8ab7ca5..0dbd7c5 100644
--- a/mpact/sim/decoder/bin_format_visitor.cc
+++ b/mpact/sim/decoder/bin_format_visitor.cc
@@ -45,7 +45,7 @@
 #include "mpact/sim/decoder/instruction_encoding.h"
 #include "mpact/sim/decoder/instruction_group.h"
 #include "mpact/sim/decoder/overlay.h"
-#include "util/regexp/re2/re2.h"
+#include "re2/re2.h"
 
 namespace mpact {
 namespace sim {
diff --git a/mpact/sim/decoder/bin_format_visitor.h b/mpact/sim/decoder/bin_format_visitor.h
index 75dab56..e1ba70f 100644
--- a/mpact/sim/decoder/bin_format_visitor.h
+++ b/mpact/sim/decoder/bin_format_visitor.h
@@ -34,7 +34,7 @@
 #include "mpact/sim/decoder/bin_encoding_info.h"
 #include "mpact/sim/decoder/bin_format_contexts.h"
 #include "mpact/sim/decoder/decoder_error_listener.h"
-#include "util/regexp/re2/re2.h"
+#include "re2/re2.h"
 
 namespace mpact {
 namespace sim {
diff --git a/mpact/sim/decoder/instruction_set_visitor.cc b/mpact/sim/decoder/instruction_set_visitor.cc
index 0c9bf89..f70c5b3 100644
--- a/mpact/sim/decoder/instruction_set_visitor.cc
+++ b/mpact/sim/decoder/instruction_set_visitor.cc
@@ -45,7 +45,7 @@
 #include "mpact/sim/decoder/opcode.h"
 #include "mpact/sim/decoder/slot.h"
 #include "mpact/sim/decoder/template_expression.h"
-#include "util/regexp/re2/re2.h"
+#include "re2/re2.h"
 
 // This flag is used to set the version of the generated code. Version 1 is
 // the default version. Version 2 adds an instruction pointer to the resource
@@ -2451,8 +2451,8 @@
                   "#include "
                   "\"mpact/sim/util/asm/opcode_assembler_interface.h\"\n"
                   "#include \"mpact/sim/util/asm/resolver_interface.h\"\n"
-                  "#include \"util/regexp/re2/re2.h\"\n"
-                  "#include \"util/regexp/re2/set.h\"\n"
+                  "#include \"re2/re2.h\"\n"
+                  "#include \"re2/set.h\"\n"
                   "#include \"",
                   opcode_file_name,
                   "\"\n"
@@ -2471,8 +2471,8 @@
                   "#include "
                   "\"mpact/sim/util/asm/opcode_assembler_interface.h\"\n"
                   "#include \"mpact/sim/util/asm/resolver_interface.h\"\n"
-                  "#include \"util/regexp/re2/re2.h\"\n"
-                  "#include \"util/regexp/re2/set.h\"\n"
+                  "#include \"re2/re2.h\"\n"
+                  "#include \"re2/set.h\"\n"
                   "#include \"",
                   opcode_file_name,
                   "\"\n"
diff --git a/mpact/sim/decoder/instruction_set_visitor.h b/mpact/sim/decoder/instruction_set_visitor.h
index 82c3280..83fa3ba 100644
--- a/mpact/sim/decoder/instruction_set_visitor.h
+++ b/mpact/sim/decoder/instruction_set_visitor.h
@@ -43,7 +43,7 @@
 #include "mpact/sim/decoder/opcode.h"
 #include "mpact/sim/decoder/slot.h"
 #include "mpact/sim/decoder/template_expression.h"
-#include "util/regexp/re2/re2.h"
+#include "re2/re2.h"
 
 // This file declares the classes that interact with the antlr4 library
 // to parse an input stream and generate the parse tree, then visiting the
diff --git a/mpact/sim/decoder/mpact_sim_isa.bzl b/mpact/sim/decoder/mpact_sim_isa.bzl
index d5e0071..aab57f7 100644
--- a/mpact/sim/decoder/mpact_sim_isa.bzl
+++ b/mpact/sim/decoder/mpact_sim_isa.bzl
@@ -126,10 +126,8 @@
         lib_deps.append("@com_google_mpact-sim//mpact/sim/generic:instruction")
     if "@com_google_mpact-sim//mpact/sim/util/asm" not in deps:
         lib_deps.append("@com_google_mpact-sim//mpact/sim/util/asm")
-    if "//util/regexp/re2" not in deps:
-        lib_deps.append("//util/regexp/re2")
-    if "//util/regexp/re2:set" not in deps:
-        lib_deps.append("//util/regexp/re2:set")
+    if "@com_googlesource_code_re2//:re2" not in deps:
+        lib_deps.append("@com_googlesource_code_re2//:re2")
     if "@com_google_absl//absl/status" not in deps:
         lib_deps.append("@com_google_absl//absl/status")
     if "@com_google_absl//absl/status:statusor" not in deps:
diff --git a/mpact/sim/decoder/proto_format_visitor.cc b/mpact/sim/decoder/proto_format_visitor.cc
index 8dfb867..a2dbce5 100644
--- a/mpact/sim/decoder/proto_format_visitor.cc
+++ b/mpact/sim/decoder/proto_format_visitor.cc
@@ -44,9 +44,9 @@
 #include "mpact/sim/decoder/proto_instruction_decoder.h"
 #include "mpact/sim/decoder/proto_instruction_encoding.h"
 #include "mpact/sim/decoder/proto_instruction_group.h"
+#include "re2/re2.h"
 #include "src/google/protobuf/compiler/importer.h"
 #include "src/google/protobuf/descriptor.h"
-#include "util/regexp/re2/re2.h"
 
 namespace mpact {
 namespace sim {
diff --git a/mpact/sim/decoder/proto_format_visitor.h b/mpact/sim/decoder/proto_format_visitor.h
index 2024a59..c57730d 100644
--- a/mpact/sim/decoder/proto_format_visitor.h
+++ b/mpact/sim/decoder/proto_format_visitor.h
@@ -37,8 +37,8 @@
 #include "mpact/sim/decoder/proto_encoding_info.h"
 #include "mpact/sim/decoder/proto_format_contexts.h"
 #include "mpact/sim/decoder/proto_instruction_group.h"
+#include "re2/re2.h"
 #include "src/google/protobuf/descriptor.h"
-#include "util/regexp/re2/re2.h"
 
 // This file defines the visitor class used to generate C++ code for decoding
 // instructions encoded in protobufs.
diff --git a/mpact/sim/decoder/test/BUILD b/mpact/sim/decoder/test/BUILD
index 7719b84..caf511f 100644
--- a/mpact/sim/decoder/test/BUILD
+++ b/mpact/sim/decoder/test/BUILD
@@ -153,7 +153,6 @@
     deps = [
         ":log_sink",
         "//mpact/sim/decoder:isa_parser",
-        "//util/regexp/re2",
         "@com_google_absl//absl/flags:flag",
         "@com_google_absl//absl/log:check",
         "@com_google_absl//absl/log:log_sink_registry",
@@ -163,6 +162,7 @@
         "@com_google_absl//absl/strings",
         "@com_google_googletest//:gtest",
         "@com_google_googletest//:gtest_main",
+        "@com_googlesource_code_re2//:re2",
     ],
 )
 
@@ -373,7 +373,6 @@
     deps = [
         ":log_sink",
         "//mpact/sim/decoder:bin_format_visitor",
-        "//util/regexp/re2",
         "@com_google_absl//absl/flags:flag",
         "@com_google_absl//absl/log:check",
         "@com_google_absl//absl/log:log_sink_registry",
@@ -382,6 +381,7 @@
         "@com_google_absl//absl/strings",
         "@com_google_googletest//:gtest",
         "@com_google_googletest//:gtest_main",
+        "@com_googlesource_code_re2//:re2",
     ],
 )
 
@@ -400,7 +400,6 @@
     deps = [
         ":log_sink",
         "//mpact/sim/decoder:proto_format_visitor",
-        "//util/regexp/re2",
         "@com_google_absl//absl/flags:flag",
         "@com_google_absl//absl/log",
         "@com_google_absl//absl/log:check",
@@ -410,6 +409,7 @@
         "@com_google_absl//absl/strings",
         "@com_google_googletest//:gtest",
         "@com_google_googletest//:gtest_main",
+        "@com_googlesource_code_re2//:re2",
     ],
 )
 
diff --git a/mpact/sim/decoder/test/bin_format_visitor_test.cc b/mpact/sim/decoder/test/bin_format_visitor_test.cc
index 3738440..b1da3ed 100644
--- a/mpact/sim/decoder/test/bin_format_visitor_test.cc
+++ b/mpact/sim/decoder/test/bin_format_visitor_test.cc
@@ -25,7 +25,7 @@
 #include "absl/strings/str_cat.h"
 #include "googletest/include/gtest/gtest.h"
 #include "mpact/sim/decoder/test/log_sink.h"
-#include "util/regexp/re2/re2.h"
+#include "re2/re2.h"
 
 namespace {
 
diff --git a/mpact/sim/decoder/test/instruction_set_visitor_test.cc b/mpact/sim/decoder/test/instruction_set_visitor_test.cc
index a28b88c..d7c338d 100644
--- a/mpact/sim/decoder/test/instruction_set_visitor_test.cc
+++ b/mpact/sim/decoder/test/instruction_set_visitor_test.cc
@@ -26,7 +26,7 @@
 #include "googlemock/include/gmock/gmock.h"  // IWYU pragma: keep
 #include "googletest/include/gtest/gtest.h"
 #include "mpact/sim/decoder/test/log_sink.h"
-#include "util/regexp/re2/re2.h"
+#include "re2/re2.h"
 
 namespace mpact {
 namespace sim {
diff --git a/mpact/sim/util/asm/BUILD b/mpact/sim/util/asm/BUILD
index db3d37d..3e909d1 100644
--- a/mpact/sim/util/asm/BUILD
+++ b/mpact/sim/util/asm/BUILD
@@ -45,7 +45,6 @@
     hdrs = ["simple_assembler.h"],
     deps = [
         ":asm",
-        "//util/regexp/re2",
         "@com_github_serge1_elfio//:elfio",
         "@com_google_absl//absl/container:flat_hash_map",
         "@com_google_absl//absl/container:flat_hash_set",
@@ -55,5 +54,6 @@
         "@com_google_absl//absl/status:statusor",
         "@com_google_absl//absl/strings",
         "@com_google_absl//absl/types:span",
+        "@com_googlesource_code_re2//:re2",
     ],
 )
diff --git a/mpact/sim/util/asm/simple_assembler.cc b/mpact/sim/util/asm/simple_assembler.cc
index ff5faa1..9419fc4 100644
--- a/mpact/sim/util/asm/simple_assembler.cc
+++ b/mpact/sim/util/asm/simple_assembler.cc
@@ -41,7 +41,7 @@
 #include "mpact/sim/util/asm/opcode_assembler_interface.h"
 #include "mpact/sim/util/asm/resolver.h"
 #include "mpact/sim/util/asm/resolver_interface.h"
-#include "util/regexp/re2/re2.h"
+#include "re2/re2.h"
 
 namespace mpact {
 namespace sim {
diff --git a/mpact/sim/util/asm/simple_assembler.h b/mpact/sim/util/asm/simple_assembler.h
index 9ae2b06..e2ed324 100644
--- a/mpact/sim/util/asm/simple_assembler.h
+++ b/mpact/sim/util/asm/simple_assembler.h
@@ -33,7 +33,7 @@
 #include "elfio/elfio_symbols.hpp"
 #include "mpact/sim/util/asm/opcode_assembler_interface.h"
 #include "mpact/sim/util/asm/resolver_interface.h"
-#include "util/regexp/re2/re2.h"
+#include "re2/re2.h"
 
 // This file declares the SimpleAssembler class, which provides simple handling
 // of assembly source, including a number of assembly directives. It currently
diff --git a/mpact/sim/util/asm/test/BUILD b/mpact/sim/util/asm/test/BUILD
index fc64d46..634b617 100644
--- a/mpact/sim/util/asm/test/BUILD
+++ b/mpact/sim/util/asm/test/BUILD
@@ -74,12 +74,12 @@
         ":riscv64x_isa",
         "//mpact/sim/generic:type_helpers",
         "//mpact/sim/util/asm",
-        "//util/regexp/re2",
         "@com_google_absl//absl/base:no_destructor",
         "@com_google_absl//absl/container:flat_hash_map",
         "@com_google_absl//absl/status",
         "@com_google_absl//absl/status:statusor",
         "@com_google_absl//absl/strings",
+        "@com_googlesource_code_re2//:re2",
     ],
 )
 
@@ -92,7 +92,6 @@
         ":riscv64x_isa",
         "//mpact/sim/util/asm",
         "//mpact/sim/util/asm:simple_assembler",
-        "//util/regexp/re2",
         "@com_github_serge1_elfio//:elfio",
         "@com_google_absl//absl/base:no_destructor",
         "@com_google_absl//absl/container:flat_hash_map",
@@ -101,5 +100,6 @@
         "@com_google_absl//absl/strings",
         "@com_google_absl//absl/types:span",
         "@com_google_googletest//:gtest_main",
+        "@com_googlesource_code_re2//:re2",
     ],
 )
diff --git a/mpact/sim/util/asm/test/riscv64x_asm_test.cc b/mpact/sim/util/asm/test/riscv64x_asm_test.cc
index b3cf03d..5e425de 100644
--- a/mpact/sim/util/asm/test/riscv64x_asm_test.cc
+++ b/mpact/sim/util/asm/test/riscv64x_asm_test.cc
@@ -35,7 +35,7 @@
 #include "mpact/sim/util/asm/simple_assembler.h"
 #include "mpact/sim/util/asm/test/riscv64x_bin_encoder_interface.h"
 #include "mpact/sim/util/asm/test/riscv64x_encoder.h"
-#include "util/regexp/re2/re2.h"
+#include "re2/re2.h"
 
 // This file contains tests for the simple assembler using a very reduced
 // subset of the RISC-V ISA.
diff --git a/mpact/sim/util/asm/test/riscv_bin_setters.cc b/mpact/sim/util/asm/test/riscv_bin_setters.cc
index caca342..a411e87 100644
--- a/mpact/sim/util/asm/test/riscv_bin_setters.cc
+++ b/mpact/sim/util/asm/test/riscv_bin_setters.cc
@@ -23,7 +23,7 @@
 #include "absl/strings/str_cat.h"
 #include "absl/strings/string_view.h"
 #include "mpact/sim/generic/type_helpers.h"
-#include "util/regexp/re2/re2.h"
+#include "re2/re2.h"
 
 namespace mpact {
 namespace sim {
diff --git a/mpact/sim/util/asm/test/riscv_bin_setters.h b/mpact/sim/util/asm/test/riscv_bin_setters.h
index 6bb5245..83a435b 100644
--- a/mpact/sim/util/asm/test/riscv_bin_setters.h
+++ b/mpact/sim/util/asm/test/riscv_bin_setters.h
@@ -30,7 +30,7 @@
 #include "mpact/sim/util/asm/opcode_assembler_interface.h"
 #include "mpact/sim/util/asm/resolver_interface.h"
 #include "mpact/sim/util/asm/test/riscv_getter_helpers.h"
-#include "util/regexp/re2/re2.h"
+#include "re2/re2.h"
 
 namespace mpact {
 namespace sim {
diff --git a/repos.bzl b/repos.bzl
index 36557fa..2fde949 100644
--- a/repos.bzl
+++ b/repos.bzl
@@ -76,9 +76,9 @@
     http_archive(
         name = "com_github_serge1_elfio",
         build_file = "@com_google_mpact-sim//:external/BUILD.elfio",
-        sha256 = "767b269063fc35aba6d361139f830aa91c45dc6b77942f082666876c1aa0be0f",
-        strip_prefix = "elfio-3.9",
-        urls = ["https://github.com/serge1/ELFIO/releases/download/Release_3.9/elfio-3.9.tar.gz"],
+        sha256 = "caf49f3bf55a9c99c98ebea4b05c79281875783802e892729eea0415505f68c4",
+        strip_prefix = "elfio-3.12",
+        urls = ["https://github.com/serge1/ELFIO/releases/download/Release_3.12/elfio-3.12.tar.gz"],
     )
 
     # Antlr4 tool (java).