[LVI] Handle range attributes

Author: andjo403

llvm/lib/Analysis/LazyValueInfo.cpp

@@ -588,10 +588,14 @@ LazyValueInfoImpl::getBlockValue(Value *Val, BasicBlock *BB,
 
 static ValueLatticeElement getFromRangeMetadata(Instruction *BBI) {
   switch (BBI->getOpcode()) {
-  default: break;
-  case Instruction::Load:
+  default:
+    break;
   case Instruction::Call:
   case Instruction::Invoke:
+    if (std::optional<ConstantRange> Range = cast<CallBase>(BBI)->getRange())
+      return ValueLatticeElement::getRange(*Range);
+    [[fallthrough]];
+  case Instruction::Load:
     if (MDNode *Ranges = BBI->getMetadata(LLVMContext::MD_range))
       if (isa<IntegerType>(BBI->getType())) {
         return ValueLatticeElement::getRange(
@@ -706,10 +710,11 @@ std::optional<ValueLatticeElement>
 LazyValueInfoImpl::solveBlockValueNonLocal(Value *Val, BasicBlock *BB) {
   ValueLatticeElement Result;  // Start Undefined.
 
-  // If this is the entry block, we must be asking about an argument.  The
-  // value is overdefined.
+  // If this is the entry block, we must be asking about an argument.
   if (BB->isEntryBlock()) {
     assert(isa<Argument>(Val) && "Unknown live-in to the entry block");
+    if (std::optional<ConstantRange> Range = cast<Argument>(Val)->getRange())
+      return ValueLatticeElement::getRange(*Range);
     return ValueLatticeElement::getOverdefined();
   }
 

llvm/test/Transforms/CorrelatedValuePropagation/range.ll

@@ -1125,8 +1125,7 @@ else:
 
 define i1 @icmp_eq_range_attr(i8 range(i8 1, 0) %i) {
 ; CHECK-LABEL: @icmp_eq_range_attr(
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i8 [[I:%.*]], 0
-; CHECK-NEXT:    ret i1 [[CMP]]
+; CHECK-NEXT:    ret i1 false
 ;
   %cmp = icmp eq i8 %i, 0
   ret i1 %cmp
@@ -1147,8 +1146,7 @@ declare range(i8 -1, 1) i8 @returns_contain_zero_range_helper()
 define i1 @icmp_eq_range_return() {
 ; CHECK-LABEL: @icmp_eq_range_return(
 ; CHECK-NEXT:    [[I:%.*]] = call i8 @returns_non_zero_range_helper()
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i8 [[I]], 0
-; CHECK-NEXT:    ret i1 [[CMP]]
+; CHECK-NEXT:    ret i1 false
 ;
   %i = call i8 @returns_non_zero_range_helper()
   %cmp = icmp eq i8 %i, 0
@@ -1171,8 +1169,7 @@ declare i8 @returns_i8_helper()
 define i1 @icmp_eq_range_call() {
 ; CHECK-LABEL: @icmp_eq_range_call(
 ; CHECK-NEXT:    [[I:%.*]] = call range(i8 1, 0) i8 @returns_i8_helper()
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i8 [[I]], 0
-; CHECK-NEXT:    ret i1 [[CMP]]
+; CHECK-NEXT:    ret i1 false
 ;
   %i = call range(i8 1, 0) i8 @returns_i8_helper()
   %cmp = icmp eq i8 %i, 0