diff --git a/clang/lib/Basic/Targets/Sparc.h b/clang/lib/Basic/Targets/Sparc.h
--- a/clang/lib/Basic/Targets/Sparc.h
+++ b/clang/lib/Basic/Targets/Sparc.h
@@ -166,10 +166,15 @@
       PtrDiffType = SignedLong;
       break;
     }
-    // Up to 32 bits are lock-free atomic, but we're willing to do atomic ops
-    // on up to 64 bits.
+    // Up to 32 bits (V8) or 64 bits (V9) are lock-free atomic, but we're
+    // willing to do atomic ops on up to 64 bits.
     MaxAtomicPromoteWidth = 64;
-    MaxAtomicInlineWidth = 32;
+    if (getCPUGeneration(CPU) == CG_V9)
+      MaxAtomicInlineWidth = 64;
+    else
+      // FIXME: This isn't correct for plain V8 which lacks CAS,
+      // only for LEON 3+ and Myriad.
+      MaxAtomicInlineWidth = 32;
   }
 
   void getTargetDefines(const LangOptions &Opts,
diff --git a/clang/lib/Basic/Targets/Sparc.cpp b/clang/lib/Basic/Targets/Sparc.cpp
--- a/clang/lib/Basic/Targets/Sparc.cpp
+++ b/clang/lib/Basic/Targets/Sparc.cpp
@@ -147,19 +147,20 @@
 void SparcV8TargetInfo::getTargetDefines(const LangOptions &Opts,
                                          MacroBuilder &Builder) const {
   SparcTargetInfo::getTargetDefines(Opts, Builder);
-  switch (getCPUGeneration(CPU)) {
-  case CG_V8:
+  if (getTriple().getOS() == llvm::Triple::Solaris)
     Builder.defineMacro("__sparcv8");
-    if (getTriple().getOS() != llvm::Triple::Solaris)
+  else {
+    switch (getCPUGeneration(CPU)) {
+    case CG_V8:
+      Builder.defineMacro("__sparcv8");
       Builder.defineMacro("__sparcv8__");
-    break;
-  case CG_V9:
-    Builder.defineMacro("__sparcv9");
-    if (getTriple().getOS() != llvm::Triple::Solaris) {
+      break;
+    case CG_V9:
+      Builder.defineMacro("__sparcv9");
       Builder.defineMacro("__sparcv9__");
       Builder.defineMacro("__sparc_v9__");
+      break;
     }
-    break;
   }
   if (getTriple().getVendor() == llvm::Triple::Myriad) {
     std::string MyriadArchValue, Myriad2Value;
@@ -227,6 +228,12 @@
     Builder.defineMacro("__myriad2__", Myriad2Value);
     Builder.defineMacro("__myriad2", Myriad2Value);
   }
+  if (getCPUGeneration(CPU) == CG_V9) {
+    Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_1");
+    Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2");
+    Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4");
+    Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8");
+  }
 }
 
 void SparcV9TargetInfo::getTargetDefines(const LangOptions &Opts,
diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp
--- a/clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -347,6 +347,8 @@
   case llvm::Triple::sparcv9:
     if (const Arg *A = Args.getLastArg(options::OPT_mcpu_EQ))
       return A->getValue();
+    if (T.getArch() == llvm::Triple::sparc && T.isOSSolaris())
+      return "v9";
     return "";
 
   case llvm::Triple::x86:
diff --git a/clang/test/Preprocessor/predefined-arch-macros.c b/clang/test/Preprocessor/predefined-arch-macros.c
--- a/clang/test/Preprocessor/predefined-arch-macros.c
+++ b/clang/test/Preprocessor/predefined-arch-macros.c
@@ -3233,9 +3233,26 @@
 // RUN:     -target sparc-unknown-linux \
 // RUN:   | FileCheck -match-full-lines %s -check-prefix=CHECK_SPARC-V9
 // CHECK_SPARC-V9-NOT: #define __sparcv8 1
+// CHECK_SPARC-V9-NOT: #define __sparcv8__ 1
 // CHECK_SPARC-V9: #define __sparc_v9__ 1
 // CHECK_SPARC-V9: #define __sparcv9 1
-// CHECK_SPARC-V9-NOT: #define __sparcv8 1
+// CHECK_SPARC-V9: #define __sparcv9__ 1
+
+// RUN: %clang -E -dM %s -o - 2>&1 \
+// RUN:     -target sparc-sun-solaris \
+// RUN:   | FileCheck -match-full-lines %s -check-prefix=CHECK_SPARC_SOLARIS_GCC_ATOMICS
+// CHECK_SPARC_SOLARIS_GCC_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
+// CHECK_SPARC_SOLARIS_GCC_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
+// CHECK_SPARC_SOLARIS_GCC_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
+// CHECK_SPARC_SOLARIS_GCC_ATOMICS: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
+
+// RUN: %clang -mcpu=v8 -E -dM %s -o - 2>&1 \
+// RUN:     -target sparc-sun-solaris \
+// RUN:   | FileCheck -match-full-lines %s -check-prefix=CHECK_SPARC_SOLARIS_GCC_ATOMICS-V8
+// CHECK_SPARC_SOLARIS_GCC_ATOMICS-V8-NOT: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1
+// CHECK_SPARC_SOLARIS_GCC_ATOMICS-V8-NOT: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1
+// CHECK_SPARC_SOLARIS_GCC_ATOMICS-V8-NOT: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1
+// CHECK_SPARC_SOLARIS_GCC_ATOMICS-V8-NOT: #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1
 
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target sparcel-unknown-linux \
diff --git a/compiler-rt/test/profile/Posix/instrprof-gcov-parallel.test b/compiler-rt/test/profile/Posix/instrprof-gcov-parallel.test
--- a/compiler-rt/test/profile/Posix/instrprof-gcov-parallel.test
+++ b/compiler-rt/test/profile/Posix/instrprof-gcov-parallel.test
@@ -10,9 +10,6 @@
 RUN: llvm-cov gcov instrprof-gcov-parallel.target.gcda
 RUN: FileCheck --input-file instrprof-gcov-parallel.target.c.gcov %s
 
-# Bug 42535
-# XFAIL: sparc-target-arch
-
 # Test if the .gcda file is correctly created from one of child processes
 # and counters of all processes are recorded correctly.
 # 707 = CHILDREN * COUNT
diff --git a/compiler-rt/test/ubsan/TestCases/Float/cast-overflow.cpp b/compiler-rt/test/ubsan/TestCases/Float/cast-overflow.cpp
--- a/compiler-rt/test/ubsan/TestCases/Float/cast-overflow.cpp
+++ b/compiler-rt/test/ubsan/TestCases/Float/cast-overflow.cpp
@@ -11,9 +11,6 @@
 // FIXME: not %run %t 8 2>&1 | FileCheck %s --check-prefix=CHECK-8
 // RUN: not %run %t 9 2>&1 | FileCheck %s --check-prefix=CHECK-9
 
-// Bug 42535
-// XFAIL: sparc-target-arch
-
 // This test assumes float and double are IEEE-754 single- and double-precision.
 
 #if defined(__APPLE__)