From 8609fda0f7e4446de85f882755601ffcbd540324 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Mon, 8 Feb 2010 23:56:03 +0000
Subject: [PATCH] fix some problems handling large vectors reported in PR6230

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95616 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../InstCombineSimplifyDemanded.cpp           | 20 +++++++++++--------
 .../InstCombine/InstCombineVectorOps.cpp      |  3 ++-
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
index 03e1c69aa52..53a568466e3 100644
--- a/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
+++ b/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
@@ -767,7 +767,7 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
 /// operation, the operation is simplified, then the resultant value is
 /// returned.  This returns null if no change was made.
 Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, APInt DemandedElts,
-                                                APInt& UndefElts,
+                                                APInt &UndefElts,
                                                 unsigned Depth) {
   unsigned VWidth = cast<VectorType>(V->getType())->getNumElements();
   APInt EltMask(APInt::getAllOnesValue(VWidth));
@@ -777,13 +777,15 @@ Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, APInt DemandedElts,
     // If the entire vector is undefined, just return this info.
     UndefElts = EltMask;
     return 0;
-  } else if (DemandedElts == 0) { // If nothing is demanded, provide undef.
+  }
+  
+  if (DemandedElts == 0) { // If nothing is demanded, provide undef.
     UndefElts = EltMask;
     return UndefValue::get(V->getType());
   }
 
   UndefElts = 0;
-  if (ConstantVector *CP = dyn_cast<ConstantVector>(V)) {
+  if (ConstantVector *CV = dyn_cast<ConstantVector>(V)) {
     const Type *EltTy = cast<VectorType>(V->getType())->getElementType();
     Constant *Undef = UndefValue::get(EltTy);
 
@@ -792,23 +794,25 @@ Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, APInt DemandedElts,
       if (!DemandedElts[i]) {   // If not demanded, set to undef.
         Elts.push_back(Undef);
         UndefElts.set(i);
-      } else if (isa<UndefValue>(CP->getOperand(i))) {   // Already undef.
+      } else if (isa<UndefValue>(CV->getOperand(i))) {   // Already undef.
         Elts.push_back(Undef);
         UndefElts.set(i);
       } else {                               // Otherwise, defined.
-        Elts.push_back(CP->getOperand(i));
+        Elts.push_back(CV->getOperand(i));
       }
 
     // If we changed the constant, return it.
     Constant *NewCP = ConstantVector::get(Elts);
-    return NewCP != CP ? NewCP : 0;
-  } else if (isa<ConstantAggregateZero>(V)) {
+    return NewCP != CV ? NewCP : 0;
+  }
+  
+  if (isa<ConstantAggregateZero>(V)) {
     // Simplify the CAZ to a ConstantVector where the non-demanded elements are
     // set to undef.
     
     // Check if this is identity. If so, return 0 since we are not simplifying
     // anything.
-    if (DemandedElts == ((1ULL << VWidth) -1))
+    if (DemandedElts.isAllOnesValue())
       return 0;
     
     const Type *EltTy = cast<VectorType>(V->getType())->getElementType();
diff --git a/lib/Transforms/InstCombine/InstCombineVectorOps.cpp b/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
index f11f5578880..20fda1a2718 100644
--- a/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
+++ b/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
@@ -162,7 +162,8 @@ Instruction *InstCombiner::visitExtractElementInst(ExtractElementInst &EI) {
     // property.
     if (EI.getOperand(0)->hasOneUse() && VectorWidth != 1) {
       APInt UndefElts(VectorWidth, 0);
-      APInt DemandedMask(VectorWidth, 1 << IndexVal);
+      APInt DemandedMask(VectorWidth, 0);
+      DemandedMask.set(IndexVal);
       if (Value *V = SimplifyDemandedVectorElts(EI.getOperand(0),
                                                 DemandedMask, UndefElts)) {
         EI.setOperand(0, V);
-- 
2.34.1