diff --git a/clang/lib/Lex/InitHeaderSearch.cpp b/clang/lib/Lex/InitHeaderSearch.cpp
@@ -231,9 +231,6 @@ void InitHeaderSearch::AddDefaultCIncludePaths(const llvm::Triple &triple,
 
   if (HSOpts.UseStandardSystemIncludes) {
     switch (os) {
-    case llvm::Triple::CloudABI:
-    case llvm::Triple::ELFIAMCU:
-      break;
     case llvm::Triple::Win32:
       if (triple.getEnvironment() != llvm::Triple::Cygnus)
         break;
@@ -271,15 +268,6 @@ void InitHeaderSearch::AddDefaultCIncludePaths(const llvm::Triple &triple,
   }
 
   switch (os) {
-  case llvm::Triple::CloudABI: {
-    // <sysroot>/<triple>/include
-    SmallString<128> P = StringRef(HSOpts.ResourceDir);
-    llvm::sys::path::append(P, "../../..", triple.str(), "include");
-    AddPath(P, System, false);
-    break;
-  }
-  case llvm::Triple::RTEMS:
-    break;
   case llvm::Triple::Win32:
     switch (triple.getEnvironment()) {
     default: llvm_unreachable("Include management is handled in the driver.");
@@ -294,15 +282,7 @@ void InitHeaderSearch::AddDefaultCIncludePaths(const llvm::Triple &triple,
     break;
   }
 
-  switch (os) {
-  case llvm::Triple::CloudABI:
-  case llvm::Triple::RTEMS:
-  case llvm::Triple::ELFIAMCU:
-    break;
-  default:
-    AddPath("/usr/include", ExternCSystem, false);
-    break;
-  }
+  AddPath("/usr/include", ExternCSystem, false);
 }
 
 void InitHeaderSearch::AddDefaultCPlusPlusIncludePaths(
@@ -339,6 +319,7 @@ bool InitHeaderSearch::ShouldAddDefaultIncludePaths(
     const llvm::Triple &triple) {
   switch (triple.getOS()) {
   case llvm::Triple::AIX:
+  case llvm::Triple::ELFIAMCU:
   case llvm::Triple::Emscripten:
   case llvm::Triple::FreeBSD:
   case llvm::Triple::Fuchsia:
@@ -351,6 +332,7 @@ bool InitHeaderSearch::ShouldAddDefaultIncludePaths(
   case llvm::Triple::OpenBSD:
   case llvm::Triple::PS4:
   case llvm::Triple::PS5:
+  case llvm::Triple::RTEMS:
   case llvm::Triple::Solaris:
   case llvm::Triple::WASI:
   case llvm::Triple::ZOS:

diff --git a/clang/lib/StaticAnalyzer/Checkers/CheckSecuritySyntaxOnly.cpp b/clang/lib/StaticAnalyzer/Checkers/CheckSecuritySyntaxOnly.cpp
@@ -27,7 +27,6 @@ using namespace ento;
 static bool isArc4RandomAvailable(const ASTContext &Ctx) {
   const llvm::Triple &T = Ctx.getTargetInfo().getTriple();
   return T.getVendor() == llvm::Triple::Apple ||
-         T.getOS() == llvm::Triple::CloudABI ||
          T.isOSFreeBSD() ||
          T.isOSNetBSD() ||
          T.isOSOpenBSD() ||

diff --git a/clang/test/Analysis/security-syntax-checks.m b/clang/test/Analysis/security-syntax-checks.m
@@ -17,25 +17,6 @@
 // RUN:   -analyzer-checker=security.insecureAPI \
 // RUN:   -analyzer-checker=security.FloatLoopCounter
 
-// RUN: %clang_analyze_cc1 -triple x86_64-unknown-cloudabi %s -verify -Wno-fortify-source \
-// RUN:   -analyzer-checker=security.insecureAPI \
-// RUN:   -analyzer-checker=security.FloatLoopCounter
-
-// RUN: %clang_analyze_cc1 -triple x86_64-unknown-cloudabi %s -verify -Wno-fortify-source \
-// RUN:   -DUSE_BUILTINS \
-// RUN:   -analyzer-checker=security.insecureAPI \
-// RUN:   -analyzer-checker=security.FloatLoopCounter
-
-// RUN: %clang_analyze_cc1 -triple x86_64-unknown-cloudabi %s -verify -Wno-fortify-source \
-// RUN:   -DVARIANT \
-// RUN:   -analyzer-checker=security.insecureAPI \
-// RUN:   -analyzer-checker=security.FloatLoopCounter
-
-// RUN: %clang_analyze_cc1 -triple x86_64-unknown-cloudabi %s -verify -Wno-fortify-source \
-// RUN:   -DUSE_BUILTINS -DVARIANT \
-// RUN:   -analyzer-checker=security.insecureAPI \
-// RUN:   -analyzer-checker=security.FloatLoopCounter
-
 #ifdef USE_BUILTINS
 # define BUILTIN(f) __builtin_ ## f
 #else /* USE_BUILTINS */

diff --git a/clang/test/Driver/cloudabi.c b/clang/test/Driver/cloudabi.c
diff --git a/clang/test/Driver/cloudabi.cpp b/clang/test/Driver/cloudabi.cpp
diff --git a/clang/test/Driver/frame-pointer-elim.c b/clang/test/Driver/frame-pointer-elim.c
@@ -47,13 +47,6 @@
 // CHECK-NO-MIX-OMIT-FP-PG: '-fomit-frame-pointer' not allowed with '-pg'
 // CHECK-MIX-NO-OMIT-FP-PG-NOT: '-fomit-frame-pointer' not allowed with '-pg'
 
-// CloudABI follows the same rules as Linux.
-// RUN: %clang -### -target x86_64-unknown-cloudabi -S -O1 %s 2>&1 | \
-// RUN:   FileCheck --check-prefix=KEEP-NONE %s
-
-// RUN: %clang -### -target x86_64-unknown-cloudabi -S %s 2>&1 | \
-// RUN:   FileCheck --check-prefix=KEEP-ALL %s
-
 // NetBSD follows the same rules as Linux.
 // RUN: %clang -### -target x86_64-unknown-netbsd -S -O1 %s 2>&1 | \
 // RUN:   FileCheck --check-prefix=KEEP-NONE %s

diff --git a/clang/test/Driver/fsanitize.c b/clang/test/Driver/fsanitize.c
@@ -716,10 +716,6 @@
 // RUN: %clang --target=powerpc64le-unknown-linux-gnu -fsanitize=memory %s -### 2>&1 | FileCheck %s -check-prefix=CHECK-SANM
 // CHECK-SANM: "-fsanitize=memory"
 
-// RUN: %clang --target=aarch64-unknown-cloudabi -fsanitize=safe-stack %s -### 2>&1 | FileCheck %s -check-prefix=SAFESTACK-CLOUDABI
-// RUN: %clang --target=x86_64-unknown-cloudabi -fsanitize=safe-stack %s -### 2>&1 | FileCheck %s -check-prefix=SAFESTACK-CLOUDABI
-// SAFESTACK-CLOUDABI: "-fsanitize=safe-stack"
-
 // RUN: %clang --target=x86_64--freebsd -fsanitize=kernel-address %s -### 2>&1 | FileCheck %s -check-prefix=KERNEL-ADDRESS-FREEBSD
 // RUN: %clang --target=aarch64--freebsd -fsanitize=kernel-address %s -### 2>&1 | FileCheck %s -check-prefix=KERNEL-ADDRESS-FREEBSD
 // KERNEL-ADDRESS-FREEBSD: "-fsanitize=kernel-address"

diff --git a/clang/test/Frontend/gnu-mcount.c b/clang/test/Frontend/gnu-mcount.c
@@ -32,10 +32,6 @@
 // RUN: %clang -target armv7-unknown-rtems-gnueabihf -meabi gnu -pg -S -emit-llvm -o - %s | FileCheck %s --check-prefixes=CHECK,MCOUNT
 // RUN: %clang -target aarch64-unknown-rtems-gnueabihf -pg -S -emit-llvm -o - %s | FileCheck %s -check-prefixes=CHECK,MCOUNT
 // RUN: %clang -target aarch64-unknown-rtems-gnueabihf -meabi gnu -pg -S -emit-llvm -o - %s | FileCheck %s -check-prefixes=CHECK,MCOUNT
-// RUN: %clang -target armv7-unknown-cloudabi-gnueabihf -pg -S -emit-llvm -o - %s | FileCheck %s --check-prefixes=CHECK,MCOUNT
-// RUN: %clang -target armv7-unknown-cloudabi-gnueabihf -meabi gnu -pg -S -emit-llvm -o - %s | FileCheck %s --check-prefixes=CHECK,MCOUNT
-// RUN: %clang -target aarch64-unknown-cloudabi-gnueabihf -pg -S -emit-llvm -o - %s | FileCheck %s --check-prefixes=CHECK,MCOUNT
-// RUN: %clang -target aarch64-unknown-cloudabi-gnueabihf -meabi gnu -pg -S -emit-llvm -o - %s | FileCheck %s --check-prefixes=CHECK,MCOUNT
 
 int f() {
   return 0;

diff --git a/clang/test/Preprocessor/init-arm.c b/clang/test/Preprocessor/init-arm.c
@@ -1177,11 +1177,6 @@
 // ARMEABIHARDFP:#define __arm 1
 // ARMEABIHARDFP:#define __arm__ 1
 
-// RUN: %clang_cc1 -E -dM -ffreestanding -triple=armv6-unknown-cloudabi-eabihf < /dev/null | FileCheck -match-full-lines -check-prefix ARMV6-CLOUDABI %s
-//
-// ARMV6-CLOUDABI:#define __CloudABI__ 1
-// ARMV6-CLOUDABI:#define __arm__ 1
-
 // RUN: %clang -E -dM -ffreestanding -target arm-netbsd-eabi %s -o - | FileCheck -match-full-lines -check-prefix ARM-NETBSD %s
 
 // ARM-NETBSD-NOT:#define _LP64

diff --git a/clang/test/Preprocessor/init-x86.c b/clang/test/Preprocessor/init-x86.c
diff --git a/clang/test/Preprocessor/predefined-macros-no-warnings.c b/clang/test/Preprocessor/predefined-macros-no-warnings.c
@@ -10,7 +10,6 @@
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple aarch64_32-darwin
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple aarch64
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple aarch64-darwin
-// RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple aarch64-cloudabi
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple aarch64-freebsd
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple aarch64-fuchsia
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple aarch64-linux
@@ -26,7 +25,6 @@
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple aarch64_be-netbsd
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple arm
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple arm-darwin
-// RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple arm-cloudabi
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple arm-freebsd
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple arm-fuchsia
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple arm-linux
@@ -135,7 +133,6 @@
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple tcele
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple i686
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple i686-darwin
-// RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple i686-cloudabi
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple i686-linux
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple i686-linux-android
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple i686-dragonfly
@@ -156,7 +153,6 @@
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple i686-hurd
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple x86_64
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple x86_64-darwin
-// RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple x86_64-cloudabi
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple x86_64-linux
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple x86_64-linux-android
 // RUN: %clang_cc1 %s -Eonly -Wsystem-headers -Werror -triple x86_64-linux-openhos

diff --git a/llvm/include/llvm/MC/MCELFObjectWriter.h b/llvm/include/llvm/MC/MCELFObjectWriter.h
@@ -71,8 +71,6 @@ class MCELFObjectTargetWriter : public MCObjectTargetWriter {
 
   static uint8_t getOSABI(Triple::OSType OSType) {
     switch (OSType) {
-      case Triple::CloudABI:
-        return ELF::ELFOSABI_CLOUDABI;
       case Triple::HermitCore:
         return ELF::ELFOSABI_STANDALONE;
       case Triple::PS4:

diff --git a/llvm/include/llvm/TargetParser/Triple.h b/llvm/include/llvm/TargetParser/Triple.h
@@ -184,7 +184,6 @@ class Triple {
   enum OSType {
     UnknownOS,
 
-    CloudABI,
     Darwin,
     DragonFly,
     FreeBSD,

diff --git a/llvm/lib/TargetParser/Triple.cpp b/llvm/lib/TargetParser/Triple.cpp
@@ -208,7 +208,6 @@ StringRef Triple::getOSTypeName(OSType Kind) {
   case AMDHSA: return "amdhsa";
   case AMDPAL: return "amdpal";
   case CUDA: return "cuda";
-  case CloudABI: return "cloudabi";
   case Darwin: return "darwin";
   case DragonFly: return "dragonfly";
   case DriverKit: return "driverkit";
@@ -570,7 +569,6 @@ static Triple::VendorType parseVendor(StringRef VendorName) {
 
 static Triple::OSType parseOS(StringRef OSName) {
   return StringSwitch<Triple::OSType>(OSName)
-    .StartsWith("cloudabi", Triple::CloudABI)
     .StartsWith("darwin", Triple::Darwin)
     .StartsWith("dragonfly", Triple::DragonFly)
     .StartsWith("freebsd", Triple::FreeBSD)

diff --git a/llvm/unittests/TargetParser/TripleTest.cpp b/llvm/unittests/TargetParser/TripleTest.cpp
@@ -319,12 +319,6 @@ TEST(TripleTest, ParsedIDs) {
   EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
   EXPECT_EQ(Triple::UnknownOS, T.getOS());
 
-  T = Triple("x86_64-unknown-cloudabi");
-  EXPECT_EQ(Triple::x86_64, T.getArch());
-  EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
-  EXPECT_EQ(Triple::CloudABI, T.getOS());
-  EXPECT_EQ(Triple::UnknownEnvironment, T.getEnvironment());
-
   T = Triple("x86_64-unknown-fuchsia");
   EXPECT_EQ(Triple::x86_64, T.getArch());
   EXPECT_EQ(Triple::UnknownVendor, T.getVendor());

diff --git a/llvm/utils/gn/secondary/clang/lib/Driver/BUILD.gn b/llvm/utils/gn/secondary/clang/lib/Driver/BUILD.gn
@@ -63,7 +63,6 @@ static_library("Driver") {
     "ToolChains/BareMetal.cpp",
     "ToolChains/CSKYToolChain.cpp",
     "ToolChains/Clang.cpp",
-    "ToolChains/CloudABI.cpp",
     "ToolChains/CommonArgs.cpp",
     "ToolChains/CrossWindows.cpp",
     "ToolChains/Cuda.cpp",