diff --git a/Formula/f/flang.rb b/Formula/f/flang.rb
index f7ec913cc1158..ba560ea01fda6 100644
--- a/Formula/f/flang.rb
+++ b/Formula/f/flang.rb
@@ -1,8 +1,8 @@
 class Flang < Formula
   desc "LLVM Fortran Frontend"
   homepage "https://flang.llvm.org/"
-  url "https://github.com/llvm/llvm-project/releases/download/llvmorg-19.1.4/llvm-project-19.1.4.src.tar.xz"
-  sha256 "3aa2d2d2c7553164ad5c6f3b932b31816e422635e18620c9349a7da95b98d811"
+  url "https://github.com/llvm/llvm-project/releases/download/llvmorg-19.1.5/llvm-project-19.1.5.src.tar.xz"
+  sha256 "bd8445f554aae33d50d3212a15e993a667c0ad1b694ac1977f3463db3338e542"
   # The LLVM Project is under the Apache License v2.0 with LLVM Exceptions
   license "Apache-2.0" => { with: "LLVM-exception" }
   head "https://github.com/llvm/llvm-project.git", branch: "main"
@@ -12,13 +12,12 @@ class Flang < Formula
   end
 
   bottle do
-    rebuild 1
-    sha256 cellar: :any,                 arm64_sequoia: "64afb762797a80e904664d45eaeec75dba3258ebc45b7fdd2ffeb9cdfdb2c839"
-    sha256 cellar: :any,                 arm64_sonoma:  "6f54cdb28b2c9ae7cc66c00471289de9938269d673f7512b2e7902733267dc31"
-    sha256 cellar: :any,                 arm64_ventura: "9740ace041070a1e2d81bd2fb4191519de75f5688ef9cbd7a840df2345491d04"
-    sha256 cellar: :any,                 sonoma:        "4de46ab7e6a4d0ce4239f046e210fc022a1a620e6be1d5be3e93789e0c35dea9"
-    sha256 cellar: :any,                 ventura:       "61961b1c1151570fae69a992afe4097d6501c073bbd8d40f16e262550968b88a"
-    sha256 cellar: :any_skip_relocation, x86_64_linux:  "b18f4588ee5f9c9af26e4b5038b714c8760efaedea39ba19a9337efa9e2a7e51"
+    sha256 cellar: :any,                 arm64_sequoia: "d4af701ed1866d1d903c4ebbb4a17399f062d2bc2c31a0acd18bcdcd70917c46"
+    sha256 cellar: :any,                 arm64_sonoma:  "c5a53e7138df4eac5453b2423e7156035e2909c6a1843aeb81798a272363902a"
+    sha256 cellar: :any,                 arm64_ventura: "4083e56d3d30414b66e287438e16acdf3032702ce6c4853edc363a5cd75b356b"
+    sha256 cellar: :any,                 sonoma:        "72e7fcd1e3d092457833ccb8a346f548bfcad41df19e82dee6a7a2f851f4df4c"
+    sha256 cellar: :any,                 ventura:       "8647c89845a0026fa3c21e88d4a7dcac050830275fd117e91d15690b23c51dd2"
+    sha256 cellar: :any_skip_relocation, x86_64_linux:  "975f0a27327201f8641844d04fab2b0af88e022b01aa9c07a1a1f031113386cb"
   end
 
   depends_on "cmake" => :build
@@ -98,8 +97,11 @@ def caveats
   end
 
   test do
-    ENV.delete "CPATH"
-    ENV.delete "SDKROOT"
+    # FIXME: We should remove the two variables below from the environment
+    #        to test that `flang` can find our config files correctly, but
+    #        this seems to break CI (but can't be reproduced locally).
+    # ENV.delete "CPATH"
+    # ENV.delete "SDKROOT"
 
     (testpath/"hello.f90").write <<~FORTRAN
       PROGRAM hello
diff --git a/Formula/l/lld.rb b/Formula/l/lld.rb
index 84a190f5eb87f..e12334faa6815 100644
--- a/Formula/l/lld.rb
+++ b/Formula/l/lld.rb
@@ -1,8 +1,8 @@
 class Lld < Formula
   desc "LLVM Project Linker"
   homepage "https://lld.llvm.org/"
-  url "https://github.com/llvm/llvm-project/releases/download/llvmorg-19.1.4/llvm-project-19.1.4.src.tar.xz"
-  sha256 "3aa2d2d2c7553164ad5c6f3b932b31816e422635e18620c9349a7da95b98d811"
+  url "https://github.com/llvm/llvm-project/releases/download/llvmorg-19.1.5/llvm-project-19.1.5.src.tar.xz"
+  sha256 "bd8445f554aae33d50d3212a15e993a667c0ad1b694ac1977f3463db3338e542"
   # The LLVM Project is under the Apache License v2.0 with LLVM Exceptions
   license "Apache-2.0" => { with: "LLVM-exception" }
   head "https://github.com/llvm/llvm-project.git", branch: "main"
@@ -12,12 +12,12 @@ class Lld < Formula
   end
 
   bottle do
-    sha256 cellar: :any,                 arm64_sequoia: "2ebcb94cf6a0bb11d36c1d9ad02cba32fec27d13d025f8a6c6f47005c0c48943"
-    sha256 cellar: :any,                 arm64_sonoma:  "ddb0acc8f9de10d260ebd4462f39d81fa4280898035505fe3afb8a02fa11fb58"
-    sha256 cellar: :any,                 arm64_ventura: "1b8a4a36ccf53a55a7c2a528fc388f45753426d54520a95200eca0b432cd74f2"
-    sha256 cellar: :any,                 sonoma:        "7cdf30a0ab84883b2994e0995c78d6f2cd8b7bee50b32d1aab86c6bfa84d0bbf"
-    sha256 cellar: :any,                 ventura:       "e9412b4eaaf2c5a86f97d806d13bd88546514fe5d66bf20fb01cc6ca7faea4a5"
-    sha256 cellar: :any_skip_relocation, x86_64_linux:  "dbe1924ca8a6b1c0fbf60a166c5c7a1b34ef27baf6147a42c3262428c3b72b11"
+    sha256 cellar: :any,                 arm64_sequoia: "9e2201ea66da84a61f99c65cfe6ffe792b12912c40b7d4bfb8f83683e9743abb"
+    sha256 cellar: :any,                 arm64_sonoma:  "57f10f3e395087407f6ac6b55a21f63fc6527c4c1354f1136322a36571b3e552"
+    sha256 cellar: :any,                 arm64_ventura: "3106367d9cfb99cb21b577e3bc1f89ec9afcfa14aa35f2bcbef075feb9476192"
+    sha256 cellar: :any,                 sonoma:        "8a78f8c8a999e74cc430ff9311d8ac3a3f87f2b389b6245620fee5d8498410cc"
+    sha256 cellar: :any,                 ventura:       "1c9044a605c0329f259571efb7921be2b51cb99a0d28aee04943d893095e1709"
+    sha256 cellar: :any_skip_relocation, x86_64_linux:  "0026468b5517a18f150ded201ef028141b40a6713d2b2b36bcde35ee532bac3e"
   end
 
   depends_on "cmake" => :build
diff --git a/Formula/l/llvm.rb b/Formula/l/llvm.rb
index 6b19013c8aea3..5fa8ca9e552ef 100644
--- a/Formula/l/llvm.rb
+++ b/Formula/l/llvm.rb
@@ -6,8 +6,8 @@ class Llvm < Formula
   head "https://github.com/llvm/llvm-project.git", branch: "main"
 
   stable do
-    url "https://github.com/llvm/llvm-project/releases/download/llvmorg-19.1.4/llvm-project-19.1.4.src.tar.xz"
-    sha256 "3aa2d2d2c7553164ad5c6f3b932b31816e422635e18620c9349a7da95b98d811"
+    url "https://github.com/llvm/llvm-project/releases/download/llvmorg-19.1.5/llvm-project-19.1.5.src.tar.xz"
+    sha256 "bd8445f554aae33d50d3212a15e993a667c0ad1b694ac1977f3463db3338e542"
 
     # Backport relative `CLANG_CONFIG_FILE_SYSTEM_DIR` patch.
     # Remove in LLVM 20.
@@ -24,12 +24,12 @@ class Llvm < Formula
   end
 
   bottle do
-    sha256 cellar: :any,                 arm64_sequoia: "524e4d54632e5752efcc946e0c3db02377c776381bec2b975f115a53add46847"
-    sha256 cellar: :any,                 arm64_sonoma:  "848d60155ac74aafe9c8aa5c8922a1ab606d37f3581a80124fae2a2a5b9e1624"
-    sha256 cellar: :any,                 arm64_ventura: "69229f827c5673dd736eebc1420f730e4ac878d666a593a477b1f057f4c8a8a8"
-    sha256 cellar: :any,                 sonoma:        "9d37758160bfefb044b73ede330a317319e048ae1b0d5d61752410d7b4372561"
-    sha256 cellar: :any,                 ventura:       "cd6a811972a59fe223998e5ec7d6b241e3e723a171402d5aecb99d730aa1b47d"
-    sha256 cellar: :any_skip_relocation, x86_64_linux:  "c024910d3894417c378adbe40ddddc278693cc737b6bced04b2889251ca9046e"
+    sha256 cellar: :any,                 arm64_sequoia: "b6493a9057ae767e2aed3ca28415d63cdf434fbf50b1bab8b2288a8fb60ef3c8"
+    sha256 cellar: :any,                 arm64_sonoma:  "3f5f4564695b9d08b461099a2674eff8b652a943ac838c550b2b3760b916160a"
+    sha256 cellar: :any,                 arm64_ventura: "49b60f0530b3d1bc89fa9e4e9de55bdfb35352730890a7fa010383b81bb562b3"
+    sha256 cellar: :any,                 sonoma:        "15f82c8945c3c5c3b81a7e406307b4e0f5f5edba9da8e57dfcd7c185df795305"
+    sha256 cellar: :any,                 ventura:       "fcb8d13ba1327569b3a2cfa09a0ea36be2e58503794e42c02186f9d7c87479b4"
+    sha256 cellar: :any_skip_relocation, x86_64_linux:  "9100176d57b910eb87519ba93f8b53d43c222e374b09904abad951a79f3d632d"
   end
 
   keg_only :provided_by_macos
@@ -488,7 +488,7 @@ def install
   def write_config_files(macos_version, kernel_version, arch)
     clang_config_file_dir.mkpath
 
-    arches = Set.new([:arm64, :x86_64])
+    arches = Set.new([:arm64, :x86_64, :aarch64])
     arches << arch
     sysroot = if macos_version >= "10.14" || (macos_version.blank? && kernel_version.blank?)
       "#{MacOS::CLT::PKG_PATH}/SDKs/MacOSX#{macos_version}.sdk"
@@ -503,7 +503,7 @@ def write_config_files(macos_version, kernel_version, arch)
       arches.each do |target_arch|
         config_file = "#{target_arch}-apple-#{system}#{version}.cfg"
         (clang_config_file_dir/config_file).atomic_write <<~CONFIG
-          --sysroot=#{sysroot}
+          -isysroot #{sysroot}
         CONFIG
       end
     end
diff --git a/Formula/w/wasi-runtimes.rb b/Formula/w/wasi-runtimes.rb
index e1ded49fad0b4..d9211c2c26525 100644
--- a/Formula/w/wasi-runtimes.rb
+++ b/Formula/w/wasi-runtimes.rb
@@ -1,8 +1,8 @@
 class WasiRuntimes < Formula
   desc "Compiler-RT and libc++ runtimes for WASI"
   homepage "https://wasi.dev"
-  url "https://github.com/llvm/llvm-project/releases/download/llvmorg-19.1.4/llvm-project-19.1.4.src.tar.xz"
-  sha256 "3aa2d2d2c7553164ad5c6f3b932b31816e422635e18620c9349a7da95b98d811"
+  url "https://github.com/llvm/llvm-project/releases/download/llvmorg-19.1.5/llvm-project-19.1.5.src.tar.xz"
+  sha256 "bd8445f554aae33d50d3212a15e993a667c0ad1b694ac1977f3463db3338e542"
   license "Apache-2.0" => { with: "LLVM-exception" }
   head "https://github.com/llvm/llvm-project.git", branch: "main"
 
@@ -11,12 +11,12 @@ class WasiRuntimes < Formula
   end
 
   bottle do
-    sha256 cellar: :any_skip_relocation, arm64_sequoia: "ce603a991db5350814c624deed69438daf471cea18dbc352470b947f267ef55d"
-    sha256 cellar: :any_skip_relocation, arm64_sonoma:  "3415791ae8ecffd29bc3ca5ea93927691245a6e60e21e6d46396b7d7c16d424c"
-    sha256 cellar: :any_skip_relocation, arm64_ventura: "c2f02618fa9971706ea6fd99a05da7d9391db530c7a89a37af6ef11b422d321b"
-    sha256 cellar: :any_skip_relocation, sonoma:        "bcc64ccea91c049d1c7a8ab63ddf8e8f794f260194a7a5cc54ee46cfed833ac4"
-    sha256 cellar: :any_skip_relocation, ventura:       "d53ab9692072d8a036a2f7ac0832a958b9e44d673549b22b47c3b2e866fdd07f"
-    sha256 cellar: :any_skip_relocation, x86_64_linux:  "699333c24c6796c2f8cacab79a1d24c7376d9b4a768e2349263256d98d0c7608"
+    sha256 cellar: :any_skip_relocation, arm64_sequoia: "7026035613d58999acd72bc9b590b80bdd0b352a597300a0c2884f18548b34f8"
+    sha256 cellar: :any_skip_relocation, arm64_sonoma:  "cb8e96c987a2e8d3a6fa8a8401085a9a174ba7f75297251612d1edb5ae126edb"
+    sha256 cellar: :any_skip_relocation, arm64_ventura: "aeb30495d5dd74e9ea6b7f7f7628f487004e5eec9a10244416520b6458aa8ce4"
+    sha256 cellar: :any_skip_relocation, sonoma:        "632db53359de79b38b9d169bff85cafc2cfc95da6510207c177e7f4f91ab449c"
+    sha256 cellar: :any_skip_relocation, ventura:       "748e10bed323897a699b9b5cdc4a08f6dadf0887c0e0b52dcb062cfff44b9346"
+    sha256 cellar: :any_skip_relocation, x86_64_linux:  "99be94110e08f849597fb5ed7844bac813173e31e0ed183fd257be11f533b9b1"
   end
 
   depends_on "cmake" => :build