From c187df2198bc6e2b038fa2d75af974644874d26f Mon Sep 17 00:00:00 2001
From: Stepan Dyatkovskiy <stpworld@narod.ru>
Date: Thu, 17 May 2012 08:56:30 +0000
Subject: [PATCH 1/1] SelectionDAGBuilder: CaseBlock, CaseRanges and CaseCmp
 changed representation of Low and High from signed to unsigned. Since
 unsigned ints usually simpler, faster and allows to reduce some extra signed
 bit checks needed before <,>,<=,>= comparisons.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156985 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../SelectionDAG/SelectionDAGBuilder.cpp      | 19 ++++++++++---------
 .../SelectionDAG/SelectionDAGBuilder.h        |  2 +-
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 4f45e76456f..a9c988bcb36 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -1578,17 +1578,18 @@ void SelectionDAGBuilder::visitSwitchCase(CaseBlock &CB,
     } else
       Cond = DAG.getSetCC(dl, MVT::i1, CondLHS, getValue(CB.CmpRHS), CB.CC);
   } else {
-    assert(CB.CC == ISD::SETLE && "Can handle only LE ranges now");
+    assert(CB.CC == ISD::SETCC_INVALID &&
+           "Condition is undefined for to-the-range belonging check.");
 
     const APInt& Low = cast<ConstantInt>(CB.CmpLHS)->getValue();
     const APInt& High  = cast<ConstantInt>(CB.CmpRHS)->getValue();
 
     SDValue CmpOp = getValue(CB.CmpMHS);
     EVT VT = CmpOp.getValueType();
-
-    if (cast<ConstantInt>(CB.CmpLHS)->isMinValue(true)) {
+    
+    if (cast<ConstantInt>(CB.CmpLHS)->isMinValue(false)) {
       Cond = DAG.getSetCC(dl, MVT::i1, CmpOp, DAG.getConstant(High, VT),
-                          ISD::SETLE);
+                          ISD::SETULE);
     } else {
       SDValue SUB = DAG.getNode(ISD::SUB, dl,
                                 VT, CmpOp, DAG.getConstant(Low, VT));
@@ -2006,7 +2007,7 @@ bool SelectionDAGBuilder::handleSmallSwitchRange(CaseRec& CR,
       CC = ISD::SETEQ;
       LHS = SV; RHS = I->High; MHS = NULL;
     } else {
-      CC = ISD::SETLE;
+      CC = ISD::SETCC_INVALID; 
       LHS = I->Low; MHS = SV; RHS = I->High;
     }
 
@@ -2038,7 +2039,7 @@ static inline bool areJTsAllowed(const TargetLowering &TLI) {
 
 static APInt ComputeRange(const APInt &First, const APInt &Last) {
   uint32_t BitWidth = std::max(Last.getBitWidth(), First.getBitWidth()) + 1;
-  APInt LastExt = Last.sext(BitWidth), FirstExt = First.sext(BitWidth);
+  APInt LastExt = Last.zext(BitWidth), FirstExt = First.zext(BitWidth);
   return (LastExt - FirstExt + 1ULL);
 }
 
@@ -2104,7 +2105,7 @@ bool SelectionDAGBuilder::handleJTSwitchCase(CaseRec &CR,
     const APInt &Low = cast<ConstantInt>(I->Low)->getValue();
     const APInt &High = cast<ConstantInt>(I->High)->getValue();
 
-    if (Low.sle(TEI) && TEI.sle(High)) {
+    if (Low.ule(TEI) && TEI.ule(High)) {
       DestBBs.push_back(I->BB);
       if (TEI==High)
         ++I;
@@ -2261,7 +2262,7 @@ bool SelectionDAGBuilder::handleBTSplitSwitchCase(CaseRec& CR,
   // Create a CaseBlock record representing a conditional branch to
   // the LHS node if the value being switched on SV is less than C.
   // Otherwise, branch to LHS.
-  CaseBlock CB(ISD::SETLT, SV, C, NULL, TrueBB, FalseBB, CR.CaseBB);
+  CaseBlock CB(ISD::SETULT, SV, C, NULL, TrueBB, FalseBB, CR.CaseBB);
 
   if (CR.CaseBB == SwitchBB)
     visitSwitchCase(CB, SwitchBB);
@@ -2333,7 +2334,7 @@ bool SelectionDAGBuilder::handleBitTestsSwitchCase(CaseRec& CR,
   // Optimize the case where all the case values fit in a
   // word without having to subtract minValue. In this case,
   // we can optimize away the subtraction.
-  if (minValue.isNonNegative() && maxValue.slt(IntPtrBits)) {
+  if (maxValue.ult(IntPtrBits)) {
     cmpRange = maxValue;
   } else {
     lowBound = minValue;
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
index 8393b414926..00e7aa1c1c1 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
@@ -187,7 +187,7 @@ private:
       assert(isa<ConstantInt>(C1.Low) && isa<ConstantInt>(C2.High));
       const ConstantInt* CI1 = cast<const ConstantInt>(C1.Low);
       const ConstantInt* CI2 = cast<const ConstantInt>(C2.High);
-      return CI1->getValue().slt(CI2->getValue());
+      return CI1->getValue().ult(CI2->getValue());
     }
   };
 
-- 
2.34.1