Update LLVM (#3956)

Fix use of newly deprecated API

MODULE.bazel

@@ -105,8 +105,8 @@ bazel_dep(name = "zstd", version = "1.5.5.bcr.1", repo_name = "llvm_zstd")
 
 # We pin to specific upstream commits and try to track top-of-tree reasonably
 # closely rather than pinning to a specific release.
-# HEAD as of 2024-04-30.
-llvm_project_version = "a7b968a57834a0e522505b56fab0ca4b979cb68f"
+# HEAD as of 2024-05-17.
+llvm_project_version = "a68d20e986053ec571223a9f3ead3e146a27dc82"
 
 # Load a repository for the raw llvm-project, pre-overlay.
 http_archive(
@@ -117,7 +117,7 @@ http_archive(
         "@carbon//bazel/llvm_project:0001_Patch_for_mallinfo2_when_using_Bazel_build_system.patch",
         "@carbon//bazel/llvm_project:0002_Added_Bazel_build_for_compiler_rt_fuzzer.patch",
     ],
-    sha256 = "57c598287c774ff0a6919de6bcdf331bb60bb962f8ba74b4ce6a3fc0cb6aaa0c",
+    sha256 = "4c53512522cfd625a75aa7f201e6932f18ebf3fbe8ee89e05883c3d30ca935ac",
     strip_prefix = "llvm-project-{0}".format(llvm_project_version),
     urls = ["https://github.com/llvm/llvm-project/archive/{0}.tar.gz".format(llvm_project_version)],
 )

MODULE.bazel.lock

@@ -1,6 +1,6 @@
 {
   "lockFileVersion": 6,
-  "moduleFileHash": "93b7acb43f1cabce8291aa0a0f87b56afabbfb021e6625c01be806a93726e716",
+  "moduleFileHash": "e8ab8befa6e8b97ea295cf5ec5b694124bd41d0842fc98875746a48ee4108eaf",
   "flags": {
     "cmdRegistries": [
       "https://bcr.bazel.build/"
@@ -70,10 +70,10 @@
                   "@carbon//bazel/llvm_project:0001_Patch_for_mallinfo2_when_using_Bazel_build_system.patch",
                   "@carbon//bazel/llvm_project:0002_Added_Bazel_build_for_compiler_rt_fuzzer.patch"
                 ],
-                "sha256": "57c598287c774ff0a6919de6bcdf331bb60bb962f8ba74b4ce6a3fc0cb6aaa0c",
-                "strip_prefix": "llvm-project-a7b968a57834a0e522505b56fab0ca4b979cb68f",
+                "sha256": "4c53512522cfd625a75aa7f201e6932f18ebf3fbe8ee89e05883c3d30ca935ac",
+                "strip_prefix": "llvm-project-a68d20e986053ec571223a9f3ead3e146a27dc82",
                 "urls": [
-                  "https://github.com/llvm/llvm-project/archive/a7b968a57834a0e522505b56fab0ca4b979cb68f.tar.gz"
+                  "https://github.com/llvm/llvm-project/archive/a68d20e986053ec571223a9f3ead3e146a27dc82.tar.gz"
                 ],
                 "name": "llvm-raw"
               },

common/string_helpers.cpp

@@ -38,7 +38,7 @@ auto UnescapeStringLiteral(llvm::StringRef source, const int hashtag_num,
   while (i < source.size()) {
     char c = source[i];
     if (i + hashtag_num < source.size() &&
-        source.slice(i, i + hashtag_num + 1).equals(escape)) {
+        source.slice(i, i + hashtag_num + 1) == escape) {
       i += hashtag_num + 1;
       if (i == source.size()) {
         return std::nullopt;