Reapply r155682, making constant folding more consistent, with a fix to work

properly with how the code handles all-undef PHI nodes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155721 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Analysis/ConstantFolding.cpp b/lib/Analysis/ConstantFolding.cpp
index 783c32e6669d806bc9d502c621d1d0a25d5361f5..7ced848aa1b63a4800cb69a446f059309f1b17d2 100644 (file)
--- a/lib/Analysis/ConstantFolding.cpp
+++ b/lib/Analysis/ConstantFolding.cpp
@@ -780,14 +780,21 @@ Constant *llvm::ConstantFoldInstruction(Instruction *I,
       // all operands are constants.
       if (isa<UndefValue>(Incoming))
         continue;
-      // If the incoming value is not a constant, or is a different constant to
-      // the one we saw previously, then give up.
+      // If the incoming value is not a constant, then give up.
       Constant *C = dyn_cast<Constant>(Incoming);
-      if (!C || (CommonValue && C != CommonValue))
+      if (!C)
+        return 0;
+      // Fold the PHI's operands.
+      if (ConstantExpr *NewC = dyn_cast<ConstantExpr>(C))
+        C = ConstantFoldConstantExpression(NewC, TD, TLI);
+      // If the incoming value is a different constant to
+      // the one we saw previously, then give up.
+      if (CommonValue && C != CommonValue)
         return 0;
       CommonValue = C;
     }
 
+
     // If we reach here, all incoming values are the same constant or undef.
     return CommonValue ? CommonValue : UndefValue::get(PN->getType());
   }
@@ -795,12 +802,18 @@ 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/InstCombine/phi.ll b/test/Transforms/InstCombine/phi.ll
index 219545c2eaa81ba0a1f40f81d63af9f60546f723..1c307d430f3f854a59be24f78d089c4c2ce533e7 100644 (file)
--- a/test/Transforms/InstCombine/phi.ll
+++ b/test/Transforms/InstCombine/phi.ll
@@ -620,3 +620,13 @@ end:
 ; CHECK-NOT: phi i32
 ; CHECK: ret i1 %z
 }
+
+; CHECK: @test27(
+; CHECK: ret i32 undef
+define i32 @test27(i1 %b) {
+entry:
+  br label %done
+done:
+  %y = phi i32 [ undef, %entry ]
+  ret i32 %y
+}

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
+}
+