[PATCH] D34538: Handle ConstantExpr correctly in SelectionDAGBuilder

[Benoit Vey via Phabricator via llvm-commits]

Praetonus created this revision.

This change fixes a bug in `SelectionDAGBuilder::visitInsertValue` and `SelectionDAGBuilder::visitExtractValue` where constant expressions (`InsertValueConstantExpr` and `ExtractValueConstantExpr`) would be treated as non-constant instructions (`InsertValueInst` and `ExtractValueInst`). This bug resulted in an incorrect memory access, which manifested as an assertion failure in `SDValue::SDValue`.

Fixes PR#33094 <https://bugs.llvm.org/show_bug.cgi?id=33094>.


https://reviews.llvm.org/D34538

Files:
  lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
  lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h


Index: lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
===================================================================
--- lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
+++ lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
@@ -38,7 +38,6 @@
 class CallInst;
 class DbgValueInst;
 class ExtractElementInst;
-class ExtractValueInst;
 class FCmpInst;
 class FPExtInst;
 class FPToSIInst;
@@ -53,7 +52,6 @@
 class IndirectBrInst;
 class InvokeInst;
 class InsertElementInst;
-class InsertValueInst;
 class Instruction;
 class LoadInst;
 class MachineBasicBlock;
@@ -859,8 +857,8 @@
   void visitInsertElement(const User &I);
   void visitShuffleVector(const User &I);
 
-  void visitExtractValue(const ExtractValueInst &I);
-  void visitInsertValue(const InsertValueInst &I);
+  void visitExtractValue(const User &I);
+  void visitInsertValue(const User &I);
   void visitLandingPad(const LandingPadInst &I);
 
   void visitGetElementPtr(const User &I);
Index: lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -3220,15 +3220,21 @@
   setValue(&I, DAG.getBuildVector(VT, DL, Ops));
 }
 
-void SelectionDAGBuilder::visitInsertValue(const InsertValueInst &I) {
+void SelectionDAGBuilder::visitInsertValue(const User &I) {
+  ArrayRef<unsigned> Indices;
+  if (const InsertValueInst *IV = dyn_cast<InsertValueInst>(&I))
+    Indices = IV->getIndices();
+  else if (const ConstantExpr *IV = dyn_cast<ConstantExpr>(&I))
+    Indices = IV->getIndices();
+
   const Value *Op0 = I.getOperand(0);
   const Value *Op1 = I.getOperand(1);
   Type *AggTy = I.getType();
   Type *ValTy = Op1->getType();
   bool IntoUndef = isa<UndefValue>(Op0);
   bool FromUndef = isa<UndefValue>(Op1);
 
-  unsigned LinearIndex = ComputeLinearIndex(AggTy, I.getIndices());
+  unsigned LinearIndex = ComputeLinearIndex(AggTy, Indices);
 
   const TargetLowering &TLI = DAG.getTargetLoweringInfo();
   SmallVector<EVT, 4> AggValueVTs;
@@ -3268,13 +3274,19 @@
                            DAG.getVTList(AggValueVTs), Values));
 }
 
-void SelectionDAGBuilder::visitExtractValue(const ExtractValueInst &I) {
+void SelectionDAGBuilder::visitExtractValue(const User &I) {
+  ArrayRef<unsigned> Indices;
+  if (const ExtractValueInst *EV = dyn_cast<ExtractValueInst>(&I))
+    Indices = EV->getIndices();
+  else if (const ConstantExpr *EV = dyn_cast<ConstantExpr>(&I))
+    Indices = EV->getIndices();
+
   const Value *Op0 = I.getOperand(0);
   Type *AggTy = Op0->getType();
   Type *ValTy = I.getType();
   bool OutOfUndef = isa<UndefValue>(Op0);
 
-  unsigned LinearIndex = ComputeLinearIndex(AggTy, I.getIndices());
+  unsigned LinearIndex = ComputeLinearIndex(AggTy, Indices);
 
   const TargetLowering &TLI = DAG.getTargetLoweringInfo();
   SmallVector<EVT, 4> ValValueVTs;


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