Use ConstantExpr::getExtractElement when constant-folding vectors

instead of getAggregateElement. This has the advantage of being
more consistent and allowing higher-level constant folding to
procede even if an inner extract element cannot be folded.

Make ConstantFoldInstruction call ConstantFoldConstantExpression
on the instruction's operands, making it more consistent with
ConstantFoldConstantExpression itself. This makes sure that
ConstantExprs get TargetData-aware folding before being handed
off as operands for further folding.

This causes more expressions to be folded, but due to a known
shortcoming in constant folding, this currently has the side effect
of stripping a few more nuw and inbounds flags in the non-targetdata
side of constant-fold-gep.ll. This is mostly harmless.

This fixes rdar://11324230.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155682 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Analysis/ConstantFolding.cpp b/lib/Analysis/ConstantFolding.cpp
index 783c32e6669d806bc9d502c621d1d0a25d5361f5..59248c9ca0ae7f86f2db6f5220671481df0171c3 100644 (file)
--- a/lib/Analysis/ConstantFolding.cpp
+++ b/lib/Analysis/ConstantFolding.cpp
@@ -788,6 +788,10 @@ Constant *llvm::ConstantFoldInstruction(Instruction *I,
       CommonValue = C;
     }
 
+    // Fold the PHI's operands.
+    if (ConstantExpr *NewCE = dyn_cast<ConstantExpr>(CommonValue))
+      CommonValue = ConstantFoldConstantExpression(NewCE, TD, TLI);
+
     // If we reach here, all incoming values are the same constant or undef.
     return CommonValue ? CommonValue : UndefValue::get(PN->getType());
   }
@@ -795,12 +799,18 @@ Constant *llvm::ConstantFoldInstruction(Instruction *I,
   // Scan the operand list, checking to see if they are all constants, if so,
   // hand off to ConstantFoldInstOperands.
   SmallVector<Constant*, 8> Ops;
-  for (User::op_iterator i = I->op_begin(), e = I->op_end(); i != e; ++i)
-    if (Constant *Op = dyn_cast<Constant>(*i))
-      Ops.push_back(Op);
-    else
+  for (User::op_iterator i = I->op_begin(), e = I->op_end(); i != e; ++i) {
+    Constant *Op = dyn_cast<Constant>(*i);
+    if (!Op)
       return 0;  // All operands not constant!
 
+    // Fold the Instruction's operands.
+    if (ConstantExpr *NewCE = dyn_cast<ConstantExpr>(Op))
+      Op = ConstantFoldConstantExpression(NewCE, TD, TLI);
+
+    Ops.push_back(Op);
+  }
+
   if (const CmpInst *CI = dyn_cast<CmpInst>(I))
     return ConstantFoldCompareInstOperands(CI->getPredicate(), Ops[0], Ops[1],
                                            TD, TLI);

diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp
index 9b1c756b7de4685fcba0fa9e802ceedeb6be2f94..a4ffddb5c4bb74525ebdfc0f8f19f3bee960dee3 100644 (file)
--- a/lib/VMCore/ConstantFold.cpp
+++ b/lib/VMCore/ConstantFold.cpp
@@ -55,13 +55,12 @@ static Constant *BitCastConstantVector(Constant *CV, VectorType *DstTy) {
   
   Type *DstEltTy = DstTy->getElementType();
 
-  // Check to verify that all elements of the input are simple.
   SmallVector<Constant*, 16> Result;
+  Type *Ty = IntegerType::get(CV->getContext(), 32);
   for (unsigned i = 0; i != NumElts; ++i) {
-    Constant *C = CV->getAggregateElement(i);
-    if (C == 0) return 0;
+    Constant *C =
+      ConstantExpr::getExtractElement(CV, ConstantInt::get(Ty, i));
     C = ConstantExpr::getBitCast(C, DstEltTy);
-    if (isa<ConstantExpr>(C)) return 0;
     Result.push_back(C);
   }
 
@@ -553,9 +552,12 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, Constant *V,
     SmallVector<Constant*, 16> res;
     VectorType *DestVecTy = cast<VectorType>(DestTy);
     Type *DstEltTy = DestVecTy->getElementType();
-    for (unsigned i = 0, e = V->getType()->getVectorNumElements(); i != e; ++i)
-      res.push_back(ConstantExpr::getCast(opc,
-                                          V->getAggregateElement(i), DstEltTy));
+    Type *Ty = IntegerType::get(V->getContext(), 32);
+    for (unsigned i = 0, e = V->getType()->getVectorNumElements(); i != e; ++i) {
+      Constant *C =
+        ConstantExpr::getExtractElement(V, ConstantInt::get(Ty, i));
+      res.push_back(ConstantExpr::getCast(opc, C, DstEltTy));
+    }
     return ConstantVector::get(res);
   }
 
@@ -696,12 +698,13 @@ Constant *llvm::ConstantFoldSelectInstruction(Constant *Cond,
   // If the condition is a vector constant, fold the result elementwise.
   if (ConstantVector *CondV = dyn_cast<ConstantVector>(Cond)) {
     SmallVector<Constant*, 16> Result;
+    Type *Ty = IntegerType::get(CondV->getContext(), 32);
     for (unsigned i = 0, e = V1->getType()->getVectorNumElements(); i != e;++i){
       ConstantInt *Cond = dyn_cast<ConstantInt>(CondV->getOperand(i));
       if (Cond == 0) break;
       
-      Constant *Res = (Cond->getZExtValue() ? V1 : V2)->getAggregateElement(i);
-      if (Res == 0) break;
+      Constant *V = Cond->isNullValue() ? V2 : V1;
+      Constant *Res = ConstantExpr::getExtractElement(V, ConstantInt::get(Ty, i));
       Result.push_back(Res);
     }
     
@@ -760,16 +763,16 @@ Constant *llvm::ConstantFoldInsertElementInstruction(Constant *Val,
   const APInt &IdxVal = CIdx->getValue();
   
   SmallVector<Constant*, 16> Result;
+  Type *Ty = IntegerType::get(Val->getContext(), 32);
   for (unsigned i = 0, e = Val->getType()->getVectorNumElements(); i != e; ++i){
     if (i == IdxVal) {
       Result.push_back(Elt);
       continue;
     }
     
-    if (Constant *C = Val->getAggregateElement(i))
-      Result.push_back(C);
-    else
-      return 0;
+    Constant *C =
+      ConstantExpr::getExtractElement(Val, ConstantInt::get(Ty, i));
+    Result.push_back(C);
   }
   
   return ConstantVector::get(Result);
@@ -801,11 +804,15 @@ Constant *llvm::ConstantFoldShuffleVectorInstruction(Constant *V1,
     Constant *InElt;
     if (unsigned(Elt) >= SrcNumElts*2)
       InElt = UndefValue::get(EltTy);
-    else if (unsigned(Elt) >= SrcNumElts)
-      InElt = V2->getAggregateElement(Elt - SrcNumElts);
-    else
-      InElt = V1->getAggregateElement(Elt);
-    if (InElt == 0) return 0;
+    else if (unsigned(Elt) >= SrcNumElts) {
+      Type *Ty = IntegerType::get(V2->getContext(), 32);
+      InElt =
+        ConstantExpr::getExtractElement(V2,
+                                        ConstantInt::get(Ty, Elt - SrcNumElts));
+    } else {
+      Type *Ty = IntegerType::get(V1->getContext(), 32);
+      InElt = ConstantExpr::getExtractElement(V1, ConstantInt::get(Ty, Elt));
+    }
     Result.push_back(InElt);
   }
 
@@ -1130,16 +1137,17 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
   } else if (VectorType *VTy = dyn_cast<VectorType>(C1->getType())) {
     // Perform elementwise folding.
     SmallVector<Constant*, 16> Result;
+    Type *Ty = IntegerType::get(VTy->getContext(), 32);
     for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
-      Constant *LHS = C1->getAggregateElement(i);
-      Constant *RHS = C2->getAggregateElement(i);
-      if (LHS == 0 || RHS == 0) break;
+      Constant *LHS =
+        ConstantExpr::getExtractElement(C1, ConstantInt::get(Ty, i));
+      Constant *RHS =
+        ConstantExpr::getExtractElement(C2, ConstantInt::get(Ty, i));
       
       Result.push_back(ConstantExpr::get(Opcode, LHS, RHS));
     }
     
-    if (Result.size() == VTy->getNumElements())
-      return ConstantVector::get(Result);
+    return ConstantVector::get(Result);
   }
 
   if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
@@ -1697,17 +1705,18 @@ Constant *llvm::ConstantFoldCompareInstruction(unsigned short pred,
     // If we can constant fold the comparison of each element, constant fold
     // the whole vector comparison.
     SmallVector<Constant*, 4> ResElts;
+    Type *Ty = IntegerType::get(C1->getContext(), 32);
     // Compare the elements, producing an i1 result or constant expr.
     for (unsigned i = 0, e = C1->getType()->getVectorNumElements(); i != e;++i){
-      Constant *C1E = C1->getAggregateElement(i);
-      Constant *C2E = C2->getAggregateElement(i);
-      if (C1E == 0 || C2E == 0) break;
+      Constant *C1E =
+        ConstantExpr::getExtractElement(C1, ConstantInt::get(Ty, i));
+      Constant *C2E =
+        ConstantExpr::getExtractElement(C2, ConstantInt::get(Ty, i));
       
       ResElts.push_back(ConstantExpr::getCompare(pred, C1E, C2E));
     }
     
-    if (ResElts.size() == C1->getType()->getVectorNumElements())
-      return ConstantVector::get(ResElts);
+    return ConstantVector::get(ResElts);
   }
 
   if (C1->getType()->isFloatingPointTy()) {

diff --git a/test/Other/constant-fold-gep.ll b/test/Other/constant-fold-gep.ll
index d28c178588bbb3e7b4667b71ec886e6dc13a6a91..eafb16e23e9e44a3e49a509a70c3eb50f03df7a5 100644 (file)
--- a/test/Other/constant-fold-gep.ll
+++ b/test/Other/constant-fold-gep.ll
@@ -263,10 +263,10 @@ define i1* @hoo1() nounwind {
 ; OPT:   ret i64 ptrtoint (double* getelementptr ({ i1, double }* null, i64 0, i32 1) to i64)
 ; OPT: }
 ; OPT: define i64 @fc() nounwind {
-; OPT:   ret i64 mul nuw (i64 ptrtoint (double* getelementptr (double* null, i32 1) to i64), i64 2)
+; OPT:   ret i64 mul (i64 ptrtoint (double* getelementptr (double* null, i32 1) to i64), i64 2)
 ; OPT: }
 ; OPT: define i64 @fd() nounwind {
-; OPT:   ret i64 mul nuw (i64 ptrtoint (double* getelementptr (double* null, i32 1) to i64), i64 11)
+; OPT:   ret i64 mul (i64 ptrtoint (double* getelementptr (double* null, i32 1) to i64), i64 11)
 ; OPT: }
 ; OPT: define i64 @fe() nounwind {
 ; OPT:   ret i64 ptrtoint (double* getelementptr ({ double, float, double, double }* null, i64 0, i32 2) to i64)
@@ -433,7 +433,7 @@ define i64* @fO() nounwind {
 ; PLAIN:   ret i32* %t
 ; PLAIN: }
 ; OPT: define i32* @fZ() nounwind {
-; OPT:   ret i32* getelementptr inbounds (i32* getelementptr inbounds ([3 x { i32, i32 }]* @ext, i64 0, i64 1, i32 0), i64 1)
+; OPT:   ret i32* getelementptr (i32* getelementptr inbounds ([3 x { i32, i32 }]* @ext, i64 0, i64 1, i32 0), i64 1)
 ; OPT: }
 ; TO: define i32* @fZ() nounwind {
 ; TO:   ret i32* getelementptr inbounds ([3 x { i32, i32 }]* @ext, i64 0, i64 1, i32 1)

diff --git a/test/Transforms/SCCP/vector-bitcast.ll b/test/Transforms/SCCP/vector-bitcast.ll
new file mode 100644 (file)
index 0000000..b032085
--- /dev/null
+++ b/test/Transforms/SCCP/vector-bitcast.ll
@@ -0,0 +1,20 @@
+; RUN: opt -sccp -S < %s | FileCheck %s
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128-n8:16:32-S128"
+
+; CHECK: store volatile <2 x i64> zeroinitializer, <2 x i64>* %p
+; rdar://11324230
+
+define void @foo(<2 x i64>* %p) nounwind {
+entry:
+  br label %while.body.i
+
+while.body.i:                                     ; preds = %while.body.i, %entry
+  %vWorkExponent.i.033 = phi <4 x i32> [ %sub.i.i, %while.body.i ], [ <i32 939524096, i32 939524096, i32 939524096, i32 939524096>, %entry ]
+  %sub.i.i = add <4 x i32> %vWorkExponent.i.033, <i32 -8388608, i32 -8388608, i32 -8388608, i32 -8388608>
+  %0 = bitcast <4 x i32> %sub.i.i to <2 x i64>
+  %and.i119.i = and <2 x i64> %0, zeroinitializer
+  store volatile <2 x i64> %and.i119.i, <2 x i64>* %p
+  br label %while.body.i
+}
+