[SystemZ] Use CLC and IPM to implement memcmp
For now this is restricted to fixed-length comparisons with a length
in the range [1, 256], as for memcpy() and MVC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188163 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index e23c5be..1101ee1 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -58,6 +58,7 @@
#include "llvm/Target/TargetLibraryInfo.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetOptions.h"
+#include "llvm/Target/TargetSelectionDAGInfo.h"
#include <algorithm>
using namespace llvm;
@@ -5463,6 +5464,26 @@
return false;
const ConstantInt *Size = dyn_cast<ConstantInt>(I.getArgOperand(2));
+ if (Size && Size->getZExtValue() == 0) {
+ EVT CallVT = TM.getTargetLowering()->getValueType(I.getType(), true);
+ setValue(&I, DAG.getConstant(0, CallVT));
+ return true;
+ }
+
+ const Value *Arg0 = I.getArgOperand(0);
+ const Value *Arg1 = I.getArgOperand(1);
+ const Value *Arg2 = I.getArgOperand(2);
+ const TargetSelectionDAGInfo &TSI = DAG.getSelectionDAGInfo();
+ std::pair<SDValue, SDValue> Res =
+ TSI.EmitTargetCodeForMemcmp(DAG, getCurSDLoc(), DAG.getRoot(),
+ getValue(Arg0), getValue(Arg1), getValue(Arg2),
+ MachinePointerInfo(Arg0),
+ MachinePointerInfo(Arg1));
+ if (Res.first.getNode()) {
+ setValue(&I, Res.first);
+ DAG.setRoot(Res.second);
+ return true;
+ }
// memcmp(S1,S2,2) != 0 -> (*(short*)LHS != *(short*)RHS) != 0
// memcmp(S1,S2,4) != 0 -> (*(int*)LHS != *(int*)RHS) != 0