Vendor import of llvm trunk r161861:

http://llvm.org/svn/llvm-project/llvm/trunk@161861

1 files changed, 8 insertions, 14 deletions

diff --git a/lib/Transforms/InstCombine/InstCombineCasts.cpp b/lib/Transforms/InstCombine/InstCombineCasts.cpp
index 39279f4..555b442 100644
--- a/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -34,7 +34,7 @@ static Value *DecomposeSimpleLinearExpr(Value *Val, unsigned &Scale,
   if (BinaryOperator *I = dyn_cast<BinaryOperator>(Val)) {
     // Cannot look past anything that might overflow.
     OverflowingBinaryOperator *OBI = dyn_cast<OverflowingBinaryOperator>(Val);
-    if (OBI && !OBI->hasNoUnsignedWrap()) {
+    if (OBI && !OBI->hasNoUnsignedWrap() && !OBI->hasNoSignedWrap()) {
       Scale = 1;
       Offset = 0;
       return Val;
@@ -648,10 +648,8 @@ static bool CanEvaluateZExtd(Value *V, Type *Ty, unsigned &BitsToClear) {
   if (!I) return false;
   
   // If the input is a truncate from the destination type, we can trivially
-  // eliminate it, even if it has multiple uses.
-  // FIXME: This is currently disabled until codegen can handle this without
-  // pessimizing code, PR5997.
-  if (0 && isa<TruncInst>(I) && I->getOperand(0)->getType() == Ty)
+  // eliminate it.
+  if (isa<TruncInst>(I) && I->getOperand(0)->getType() == Ty)
     return true;
   
   // We can't extend or shrink something that has multiple uses: doing so would
@@ -992,11 +990,8 @@ static bool CanEvaluateSExtd(Value *V, Type *Ty) {
   Instruction *I = dyn_cast<Instruction>(V);
   if (!I) return false;
   
-  // If this is a truncate from the dest type, we can trivially eliminate it,
-  // even if it has multiple uses.
-  // FIXME: This is currently disabled until codegen can handle this without
-  // pessimizing code, PR5997.
-  if (0 && isa<TruncInst>(I) && I->getOperand(0)->getType() == Ty)
+  // If this is a truncate from the dest type, we can trivially eliminate it.
+  if (isa<TruncInst>(I) && I->getOperand(0)->getType() == Ty)
     return true;
   
   // We can't extend or shrink something that has multiple uses: doing so would
@@ -1341,10 +1336,9 @@ Instruction *InstCombiner::commonPointerCastTransforms(CastInst &CI) {
     // non-type-safe code.
     if (TD && GEP->hasOneUse() && isa<BitCastInst>(GEP->getOperand(0)) &&
         GEP->hasAllConstantIndices()) {
-      // We are guaranteed to get a constant from EmitGEPOffset.
-      ConstantInt *OffsetV = cast<ConstantInt>(EmitGEPOffset(GEP));
-      int64_t Offset = OffsetV->getSExtValue();
-      
+      SmallVector<Value*, 8> Ops(GEP->idx_begin(), GEP->idx_end());
+      int64_t Offset = TD->getIndexedOffset(GEP->getPointerOperandType(), Ops);
+
       // Get the base pointer input of the bitcast, and the type it points to.
       Value *OrigBase = cast<BitCastInst>(GEP->getOperand(0))->getOperand(0);
       Type *GEPIdxTy =