XCore target: add XCoreTargetLowering::isZExtFree()

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192431 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/XCore/XCoreISelLowering.cpp

@@ -166,6 +166,24 @@ XCoreTargetLowering::XCoreTargetLowering(XCoreTargetMachine &XTM)
   setMinFunctionAlignment(1);
 }
 
+bool XCoreTargetLowering::isZExtFree(SDValue Val, EVT VT2) const {
+  if (Val.getOpcode() != ISD::LOAD)
+    return false;
+
+  EVT VT1 = Val.getValueType();
+  if (!VT1.isSimple() || !VT1.isInteger() ||
+      !VT2.isSimple() || !VT2.isInteger())
+    return false;
+
+  switch (VT1.getSimpleVT().SimpleTy) {
+  default: break;
+  case MVT::i8:
+    return true;
+  }
+
+  return false;
+}
+
 SDValue XCoreTargetLowering::
 LowerOperation(SDValue Op, SelectionDAG &DAG) const {
   switch (Op.getOpcode())

lib/Target/XCore/XCoreISelLowering.h

@@ -83,6 +83,10 @@ namespace llvm {
 
     explicit XCoreTargetLowering(XCoreTargetMachine &TM);
 
+    using TargetLowering::isZExtFree;
+    virtual bool isZExtFree(SDValue Val, EVT VT2) const;
+
+
     virtual unsigned getJumpTableEncoding() const;
     virtual MVT getScalarShiftAmountTy(EVT LHSTy) const { return MVT::i32; }
 

test/CodeGen/XCore/zextfree.ll

@@ -0,0 +1,15 @@
+; RUN: llc -march=xcore < %s | FileCheck %s
+
+; CHECK-LABEL: test:
+; CHECK-NOT: zext
+define void @test(i8* %s1) {
+entry:
+  %u8 = load i8* %s1, align 1
+  %bool = icmp eq i8 %u8, 0
+  br label %BB1
+BB1:
+  br i1 %bool, label %BB1, label %BB2
+BB2:
+  br i1 %bool, label %BB1, label %BB2
+}
+