From 3139db02c8cdf83a71f04a9aeb4e295031b1e57c Mon Sep 17 00:00:00 2001
From: Robert Lytton <robert@xmos.com>
Date: Fri, 11 Oct 2013 10:26:29 +0000
Subject: [PATCH] XCore target: add XCoreTargetLowering::isZExtFree()

llvm-svn: 192431
---
 llvm/lib/Target/XCore/XCoreISelLowering.cpp | 18 ++++++++++++++++++
 llvm/lib/Target/XCore/XCoreISelLowering.h   |  4 ++++
 llvm/test/CodeGen/XCore/zextfree.ll         | 15 +++++++++++++++
 3 files changed, 37 insertions(+)
 create mode 100644 llvm/test/CodeGen/XCore/zextfree.ll

diff --git a/llvm/lib/Target/XCore/XCoreISelLowering.cpp b/llvm/lib/Target/XCore/XCoreISelLowering.cpp
index e209c29522d0..489f0a7244cb 100644
--- a/llvm/lib/Target/XCore/XCoreISelLowering.cpp
+++ b/llvm/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())
diff --git a/llvm/lib/Target/XCore/XCoreISelLowering.h b/llvm/lib/Target/XCore/XCoreISelLowering.h
index 7761b7cef6b1..2a6c8748cd68 100644
--- a/llvm/lib/Target/XCore/XCoreISelLowering.h
+++ b/llvm/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; }
 
diff --git a/llvm/test/CodeGen/XCore/zextfree.ll b/llvm/test/CodeGen/XCore/zextfree.ll
new file mode 100644
index 000000000000..48dce8865328
--- /dev/null
+++ b/llvm/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
+}
+