[LVI][CVP] Calculate with.overflow result range

In LVI, calculate the range of extractvalue(op.with.overflow(%x, %y), 0)
as the range of op(%x, %y). This is mainly useful in conjunction with
D60650: If the result of the operation is extracted in a branch guarded
against overflow, then the value of %x will be appropriately constrained
and the result range of the operation will be calculated taking that
into account.

Differential Revision: https://reviews.llvm.org/D60656

llvm-svn: 361693

Author: nikic

llvm/lib/Analysis/LazyValueInfo.cpp

@@ -430,6 +430,8 @@ namespace {
                                BasicBlock *BB);
   bool solveBlockValueCast(ValueLatticeElement &BBLV, CastInst *CI,
                            BasicBlock *BB);
+  bool solveBlockValueOverflowIntrinsic(
+      ValueLatticeElement &BBLV, WithOverflowInst *WO, BasicBlock *BB);
   void intersectAssumeOrGuardBlockValueConstantRange(Value *Val,
                                                      ValueLatticeElement &BBLV,
                                                      Instruction *BBI);
@@ -642,6 +644,11 @@ bool LazyValueInfoImpl::solveBlockValueImpl(ValueLatticeElement &Res,
 
     if (BinaryOperator *BO = dyn_cast<BinaryOperator>(BBI))
       return solveBlockValueBinaryOp(Res, BO, BB);
+
+    if (auto *EVI = dyn_cast<ExtractValueInst>(BBI))
+      if (auto *WO = dyn_cast<WithOverflowInst>(EVI->getAggregateOperand()))
+        if (EVI->getNumIndices() == 1 && *EVI->idx_begin() == 0)
+          return solveBlockValueOverflowIntrinsic(Res, WO, BB);
   }
 
   LLVM_DEBUG(dbgs() << " compute BB '" << BB->getName()
@@ -1097,6 +1104,14 @@ bool LazyValueInfoImpl::solveBlockValueBinaryOp(ValueLatticeElement &BBLV,
   };
 }
 
+bool LazyValueInfoImpl::solveBlockValueOverflowIntrinsic(
+    ValueLatticeElement &BBLV, WithOverflowInst *WO, BasicBlock *BB) {
+  return solveBlockValueBinaryOpImpl(BBLV, WO, BB,
+      [WO](const ConstantRange &CR1, const ConstantRange &CR2) {
+        return CR1.binaryOp(WO->getBinaryOp(), CR2);
+      });
+}
+
 static ValueLatticeElement getValueFromICmpCondition(Value *Val, ICmpInst *ICI,
                                                      bool isTrueDest) {
   Value *LHS = ICI->getOperand(0);

llvm/test/Transforms/CorrelatedValuePropagation/overflow_predicate.ll

@@ -470,8 +470,7 @@ define i1 @uadd_val(i8 %x, i1* %pc) {
 ; CHECK:       split:
 ; CHECK-NEXT:    [[C1:%.*]] = icmp ugt i8 [[VAL]], 100
 ; CHECK-NEXT:    store i1 [[C1]], i1* [[PC:%.*]]
-; CHECK-NEXT:    [[C2:%.*]] = icmp uge i8 [[VAL]], 100
-; CHECK-NEXT:    ret i1 [[C2]]
+; CHECK-NEXT:    ret i1 true
 ; CHECK:       trap:
 ; CHECK-NEXT:    call void @llvm.trap()
 ; CHECK-NEXT:    unreachable
@@ -506,8 +505,7 @@ define i1 @sadd_val(i8 %x, i1* %pc) {
 ; CHECK:       split:
 ; CHECK-NEXT:    [[C1:%.*]] = icmp sgt i8 [[VAL]], -28
 ; CHECK-NEXT:    store i1 [[C1]], i1* [[PC:%.*]]
-; CHECK-NEXT:    [[C2:%.*]] = icmp sge i8 [[VAL]], -28
-; CHECK-NEXT:    ret i1 [[C2]]
+; CHECK-NEXT:    ret i1 true
 ; CHECK:       trap:
 ; CHECK-NEXT:    call void @llvm.trap()
 ; CHECK-NEXT:    unreachable
@@ -542,8 +540,7 @@ define i1 @usub_val(i8 %x, i1* %pc) {
 ; CHECK:       split:
 ; CHECK-NEXT:    [[C1:%.*]] = icmp ult i8 [[VAL]], -101
 ; CHECK-NEXT:    store i1 [[C1]], i1* [[PC:%.*]]
-; CHECK-NEXT:    [[C2:%.*]] = icmp ule i8 [[VAL]], -101
-; CHECK-NEXT:    ret i1 [[C2]]
+; CHECK-NEXT:    ret i1 true
 ; CHECK:       trap:
 ; CHECK-NEXT:    call void @llvm.trap()
 ; CHECK-NEXT:    unreachable
@@ -578,8 +575,7 @@ define i1 @ssub_val(i8 %x, i1* %pc) {
 ; CHECK:       split:
 ; CHECK-NEXT:    [[C1:%.*]] = icmp slt i8 [[VAL]], 27
 ; CHECK-NEXT:    store i1 [[C1]], i1* [[PC:%.*]]
-; CHECK-NEXT:    [[C2:%.*]] = icmp sle i8 [[VAL]], 27
-; CHECK-NEXT:    ret i1 [[C2]]
+; CHECK-NEXT:    ret i1 true
 ; CHECK:       trap:
 ; CHECK-NEXT:    call void @llvm.trap()
 ; CHECK-NEXT:    unreachable
@@ -614,8 +610,7 @@ define i1 @umul_val(i8 %x, i1* %pc) {
 ; CHECK:       split:
 ; CHECK-NEXT:    [[C1:%.*]] = icmp ult i8 [[VAL]], -6
 ; CHECK-NEXT:    store i1 [[C1]], i1* [[PC:%.*]]
-; CHECK-NEXT:    [[C2:%.*]] = icmp ule i8 [[VAL]], -6
-; CHECK-NEXT:    ret i1 [[C2]]
+; CHECK-NEXT:    ret i1 true
 ; CHECK:       trap:
 ; CHECK-NEXT:    call void @llvm.trap()
 ; CHECK-NEXT:    unreachable
@@ -650,8 +645,7 @@ define i1 @smul_val_bound1(i8 %x, i1* %pc) {
 ; CHECK:       split:
 ; CHECK-NEXT:    [[C1:%.*]] = icmp slt i8 [[VAL]], 120
 ; CHECK-NEXT:    store i1 [[C1]], i1* [[PC:%.*]]
-; CHECK-NEXT:    [[C2:%.*]] = icmp sle i8 [[VAL]], 120
-; CHECK-NEXT:    ret i1 [[C2]]
+; CHECK-NEXT:    ret i1 true
 ; CHECK:       trap:
 ; CHECK-NEXT:    call void @llvm.trap()
 ; CHECK-NEXT:    unreachable
@@ -686,8 +680,7 @@ define i1 @smul_val_bound2(i8 %x, i1* %pc) {
 ; CHECK:       split:
 ; CHECK-NEXT:    [[C1:%.*]] = icmp sgt i8 [[VAL]], -120
 ; CHECK-NEXT:    store i1 [[C1]], i1* [[PC:%.*]]
-; CHECK-NEXT:    [[C2:%.*]] = icmp sge i8 [[VAL]], -120
-; CHECK-NEXT:    ret i1 [[C2]]
+; CHECK-NEXT:    ret i1 true
 ; CHECK:       trap:
 ; CHECK-NEXT:    call void @llvm.trap()
 ; CHECK-NEXT:    unreachable