[PowerPC] Add readflm/setflm intrinsics to Clang

[qiucf]

Summary

dbcfbffc adds ppc.readflm and ppc.setflm intrinsics to read or write FPSCR register. This patch adds them to Clang.

[steven.zhang]

LGTM, thank you!

clang/include/clang/Basic/BuiltinsPPC.def

 
 // Vector int128 (un)pack
 BUILTIN(__builtin_unpack_vector_int128, "ULLiV1LLLii", "")
 BUILTIN(__builtin_pack_vector_int128, "V1LLLiULLiULLi", "")
 
 // Set the floating point rounding mode
 BUILTIN(__builtin_setrnd, "di", "")
 
+// Get content from current FPSCR
+BUILTIN(__builtin_readflm, "d", "")
+
+// Set content of FPSCR, and return its content before update
+BUILTIN(__builtin_setflm, "dd", "")
+
 // Cache built-ins
 BUILTIN(__builtin_dcbf, "vvC*", "")
 
 // FIXME: Obviously incomplete.
 
 #undef BUILTIN

clang/test/CodeGen/builtins-ppc.c

void test_builtin_ppc_setrnd() {
   res = __builtin_setrnd(2);
 
   // CHECK: call double @llvm.ppc.setrnd(i32 100)
   res = __builtin_setrnd(100);
 
   // CHECK: call double @llvm.ppc.setrnd(i32 %2)
   res = __builtin_setrnd(x);
 }
+
+void test_builtin_ppc_flm() {
+  volatile double res;
+  // CHECK: call double @llvm.ppc.readflm()
+  res = __builtin_readflm();
+
+  // CHECK: call double @llvm.ppc.setflm(double %1)
+  res = __builtin_setflm(res);
+}

llvm/include/llvm/IR/IntrinsicsPowerPC.td

let TargetPrefix = "ppc" in {  // All intrinsics start with "llvm.ppc.".
   // isync instruction
   def int_ppc_isync : Intrinsic<[], [], []>;
   // lwsync is sync 1
   def int_ppc_lwsync : Intrinsic<[], [], []>;
   // eieio instruction
   def int_ppc_eieio : Intrinsic<[],[],[]>;
 
   // Get content from current FPSCR register
-  def int_ppc_readflm : Intrinsic<[llvm_double_ty], [], [IntrNoMem]>;
+  def int_ppc_readflm : GCCBuiltin<"__builtin_readflm">,
+                        Intrinsic<[llvm_double_ty], [], [IntrNoMem]>;
   // Set FPSCR register, and return previous content
-  def int_ppc_setflm : Intrinsic<[llvm_double_ty], [llvm_double_ty], []>;
+  def int_ppc_setflm : GCCBuiltin<"__builtin_setflm">,
+                       Intrinsic<[llvm_double_ty], [llvm_double_ty], []>;
 
   // Intrinsics for [double]word extended forms of divide instructions
   def int_ppc_divwe : GCCBuiltin<"__builtin_divwe">,
                       Intrinsic<[llvm_i32_ty], [llvm_i32_ty, llvm_i32_ty],
                                 [IntrNoMem]>;
   def int_ppc_divweu : GCCBuiltin<"__builtin_divweu">,
                        Intrinsic<[llvm_i32_ty], [llvm_i32_ty, llvm_i32_ty],
                                  [IntrNoMem]>;