[InstSimpliy] Use range attribute to simplify comparisons (llvm#84627)

Use the new range attribute from llvm#84617
to simplify comparisons where both sides have range information.

Author: andjo403

llvm/include/llvm/IR/Attributes.h

@@ -848,6 +848,11 @@ class AttributeList {
     return getAttributeAtIndex(FunctionIndex, Kind);
   }
 
+  /// Return the attribute for the given attribute kind for the return value.
+  Attribute getRetAttr(Attribute::AttrKind Kind) const {
+    return getAttributeAtIndex(ReturnIndex, Kind);
+  }
+
   /// Return the alignment of the return value.
   MaybeAlign getRetAlignment() const;
 

llvm/include/llvm/IR/Function.h

@@ -430,6 +430,9 @@ class LLVM_EXTERNAL_VISIBILITY Function : public GlobalObject,
   /// Return the attribute for the given attribute kind.
   Attribute getFnAttribute(StringRef Kind) const;
 
+  /// Return the attribute for the given attribute kind for the return value.
+  Attribute getRetAttribute(Attribute::AttrKind Kind) const;
+
   /// For a string attribute \p Kind, parse attribute as an integer.
   ///
   /// \returns \p Default if attribute is not present.

llvm/include/llvm/IR/InstrTypes.h

@@ -1909,6 +1909,18 @@ class CallBase : public Instruction {
   /// Determine whether the return value has the given attribute.
   bool hasRetAttr(StringRef Kind) const { return hasRetAttrImpl(Kind); }
 
+  /// Return the attribute for the given attribute kind for the return value.
+  Attribute getRetAttr(Attribute::AttrKind Kind) const {
+    Attribute RetAttr = Attrs.getRetAttr(Kind);
+    if (RetAttr.isValid())
+      return RetAttr;
+
+    // Look at the callee, if available.
+    if (const Function *F = getCalledFunction())
+      return F->getAttributes().getRetAttr(Kind);
+    return Attribute();
+  }
+
   /// Determine whether the argument or parameter has the given attribute.
   bool paramHasAttr(unsigned ArgNo, Attribute::AttrKind Kind) const;
 

llvm/lib/Analysis/InstructionSimplify.cpp

@@ -3729,6 +3729,26 @@ static Value *simplifyICmpWithIntrinsicOnLHS(CmpInst::Predicate Pred,
   }
 }
 
+/// Helper method to get range from metadata or attribute.
+static std::optional<ConstantRange> getRange(Value *V,
+                                             const InstrInfoQuery &IIQ) {
+  if (Instruction *I = dyn_cast<Instruction>(V))
+    if (MDNode *MD = IIQ.getMetadata(I, LLVMContext::MD_range))
+      return getConstantRangeFromMetadata(*MD);
+
+  Attribute Range;
+  if (const Argument *A = dyn_cast<Argument>(V)) {
+    Range = A->getAttribute(llvm::Attribute::Range);
+  } else if (const CallBase *CB = dyn_cast<CallBase>(V)) {
+    Range = CB->getRetAttr(llvm::Attribute::Range);
+  }
+
+  if (Range.isValid())
+    return Range.getRange();
+
+  return std::nullopt;
+}
+
 /// Given operands for an ICmpInst, see if we can fold the result.
 /// If not, this returns null.
 static Value *simplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
@@ -3776,24 +3796,14 @@ static Value *simplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
 
   // If both operands have range metadata, use the metadata
   // to simplify the comparison.
-  if (isa<Instruction>(RHS) && isa<Instruction>(LHS)) {
-    auto RHS_Instr = cast<Instruction>(RHS);
-    auto LHS_Instr = cast<Instruction>(LHS);
-
-    if (Q.IIQ.getMetadata(RHS_Instr, LLVMContext::MD_range) &&
-        Q.IIQ.getMetadata(LHS_Instr, LLVMContext::MD_range)) {
-      auto RHS_CR = getConstantRangeFromMetadata(
-          *RHS_Instr->getMetadata(LLVMContext::MD_range));
-      auto LHS_CR = getConstantRangeFromMetadata(
-          *LHS_Instr->getMetadata(LLVMContext::MD_range));
-
-      if (LHS_CR.icmp(Pred, RHS_CR))
+  if (std::optional<ConstantRange> RhsCr = getRange(RHS, Q.IIQ))
+    if (std::optional<ConstantRange> LhsCr = getRange(LHS, Q.IIQ)) {
+      if (LhsCr->icmp(Pred, *RhsCr))
         return ConstantInt::getTrue(ITy);
 
-      if (LHS_CR.icmp(CmpInst::getInversePredicate(Pred), RHS_CR))
+      if (LhsCr->icmp(CmpInst::getInversePredicate(Pred), *RhsCr))
         return ConstantInt::getFalse(ITy);
     }
-  }
 
   // Compare of cast, for example (zext X) != 0 -> X != 0
   if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {

llvm/lib/IR/Function.cpp

@@ -700,6 +700,10 @@ Attribute Function::getFnAttribute(StringRef Kind) const {
   return AttributeSets.getFnAttr(Kind);
 }
 
+Attribute Function::getRetAttribute(Attribute::AttrKind Kind) const {
+  return AttributeSets.getRetAttr(Kind);
+}
+
 uint64_t Function::getFnAttributeAsParsedInteger(StringRef Name,
                                                  uint64_t Default) const {
   Attribute A = getFnAttribute(Name);

llvm/test/Transforms/InstCombine/icmp-range.ll

@@ -149,6 +149,16 @@ define i1 @test_two_ranges(ptr nocapture readonly %arg1, ptr nocapture readonly
   ret i1 %rval
 }
 
+; Values' ranges overlap each other, so it can not be simplified.
+define i1 @test_two_attribute_ranges(i32 range(i32 5, 10) %arg1, i32 range(i32 8, 16) %arg2) {
+; CHECK-LABEL: @test_two_attribute_ranges(
+; CHECK-NEXT:    [[RVAL:%.*]] = icmp ult i32 [[ARG1:%.*]], [[ARG2:%.*]]
+; CHECK-NEXT:    ret i1 [[RVAL]]
+;
+  %rval = icmp ult i32 %arg2, %arg1
+  ret i1 %rval
+}
+
 ; Values' ranges do not overlap each other, so it can simplified to false.
 define i1 @test_two_ranges2(ptr nocapture readonly %arg1, ptr nocapture readonly %arg2) {
 ; CHECK-LABEL: @test_two_ranges2(
@@ -160,6 +170,35 @@ define i1 @test_two_ranges2(ptr nocapture readonly %arg1, ptr nocapture readonly
   ret i1 %rval
 }
 
+; Values' ranges do not overlap each other, so it can simplified to false.
+define i1 @test_two_argument_ranges(i32 range(i32 1, 6) %arg1, i32 range(i32 8, 16) %arg2) {
+; CHECK-LABEL: @test_two_argument_ranges(
+; CHECK-NEXT:    ret i1 false
+;
+  %rval = icmp ult i32 %arg2, %arg1
+  ret i1 %rval
+}
+
+; Values' ranges do not overlap each other, so it can simplified to false.
+define i1 @test_one_range_and_one_argument_range(ptr nocapture readonly %arg1, i32 range(i32 8, 16) %arg2) {
+; CHECK-LABEL: @test_one_range_and_one_argument_range(
+; CHECK-NEXT:    ret i1 false
+;
+  %val1 = load i32, ptr %arg1, !range !0
+  %rval = icmp ult i32 %arg2, %val1
+  ret i1 %rval
+}
+
+; Values' ranges do not overlap each other, so it can simplified to false.
+define i1 @test_one_argument_range_and_one_range(i32 range(i32 1, 6) %arg1, ptr nocapture readonly %arg2) {
+; CHECK-LABEL: @test_one_argument_range_and_one_range(
+; CHECK-NEXT:    ret i1 false
+;
+  %val1 = load i32, ptr %arg2, !range !6
+  %rval = icmp ult i32 %val1, %arg1
+  ret i1 %rval
+}
+
 ; Values' ranges do not overlap each other, so it can simplified to true.
 define i1 @test_two_ranges3(ptr nocapture readonly %arg1, ptr nocapture readonly %arg2) {
 ; CHECK-LABEL: @test_two_ranges3(
@@ -186,8 +225,8 @@ define <2 x i1> @test_two_ranges_vec(ptr nocapture readonly %arg1, ptr nocapture
 }
 
 ; Values' ranges do not overlap each other, so it can simplified to false.
-define <2 x i1> @test_two_ranges_vec_true(ptr nocapture readonly %arg1, ptr nocapture readonly %arg2) {
-; CHECK-LABEL: @test_two_ranges_vec_true(
+define <2 x i1> @test_two_ranges_vec_false(ptr nocapture readonly %arg1, ptr nocapture readonly %arg2) {
+; CHECK-LABEL: @test_two_ranges_vec_false(
 ; CHECK-NEXT:    ret <2 x i1> zeroinitializer
 ;
   %val1 = load <2 x i32>, ptr %arg1, !range !0
@@ -196,9 +235,9 @@ define <2 x i1> @test_two_ranges_vec_true(ptr nocapture readonly %arg1, ptr noca
   ret <2 x i1> %rval
 }
 
-; Values' ranges do not overlap each other, so it can simplified to false.
-define <2 x i1> @test_two_ranges_vec_false(ptr nocapture readonly %arg1, ptr nocapture readonly %arg2) {
-; CHECK-LABEL: @test_two_ranges_vec_false(
+; Values' ranges do not overlap each other, so it can simplified to true.
+define <2 x i1> @test_two_ranges_vec_true(ptr nocapture readonly %arg1, ptr nocapture readonly %arg2) {
+; CHECK-LABEL: @test_two_ranges_vec_true(
 ; CHECK-NEXT:    ret <2 x i1> <i1 true, i1 true>
 ;
   %val1 = load <2 x i32>, ptr %arg1, !range !0
@@ -207,6 +246,101 @@ define <2 x i1> @test_two_ranges_vec_false(ptr nocapture readonly %arg1, ptr noc
   ret <2 x i1> %rval
 }
 
+; Values' ranges overlap each other, so it can not be simplified.
+define <2 x i1> @test_two_argument_ranges_vec(<2 x i32> range(i32 5, 10) %arg1, <2 x i32> range(i32 8, 16) %arg2) {
+; CHECK-LABEL: @test_two_argument_ranges_vec(
+; CHECK-NEXT:    [[RVAL:%.*]] = icmp ult <2 x i32> [[VAL2:%.*]], [[VAL1:%.*]]
+; CHECK-NEXT:    ret <2 x i1> [[RVAL]]
+;
+  %rval = icmp ult <2 x i32> %arg2, %arg1
+  ret <2 x i1> %rval
+}
+
+; Values' ranges do not overlap each other, so it can simplified to false.
+define <2 x i1> @test_two_argument_ranges_vec_false(<2 x i32> range(i32 1, 6) %arg1, <2 x i32> range(i32 8, 16) %arg2) {
+; CHECK-LABEL: @test_two_argument_ranges_vec_false(
+; CHECK-NEXT:    ret <2 x i1> zeroinitializer
+;
+  %rval = icmp ult <2 x i32> %arg2, %arg1
+  ret <2 x i1> %rval
+}
+
+; Values' ranges do not overlap each other, so it can simplified to true.
+define <2 x i1> @test_two_argument_ranges_vec_true(<2 x i32> range(i32 1, 6) %arg1, <2 x i32> range(i32 8, 16) %arg2) {
+; CHECK-LABEL: @test_two_argument_ranges_vec_true(
+; CHECK-NEXT:    ret <2 x i1> <i1 true, i1 true>
+;
+  %rval = icmp ugt <2 x i32> %arg2, %arg1
+  ret <2 x i1> %rval
+}
+
+declare i32 @create_range1()
+declare range(i32 8, 16) i32 @create_range2()
+declare range(i32 1, 6) i32 @create_range3()
+
+; Values' ranges overlap each other, so it can not be simplified.
+define i1 @test_two_return_attribute_ranges_not_simplified() {
+; CHECK-LABEL: @test_two_return_attribute_ranges_not_simplified(
+; CHECK-NEXT:    [[ARG2:%.*]] = call range(i32 5, 10) i32 @create_range1()
+; CHECK-NEXT:    [[ARG1:%.*]] = call i32 @create_range2()
+; CHECK-NEXT:    [[RVAL:%.*]] = icmp ult i32 [[ARG1]], [[ARG2]]
+; CHECK-NEXT:    ret i1 [[RVAL]]
+;
+  %val1 = call range(i32 5, 10) i32 @create_range1()
+  %val2 = call i32 @create_range2()
+  %rval = icmp ult i32 %val2, %val1
+  ret i1 %rval
+}
+
+; Values' ranges do not overlap each other, so it can simplified to false.
+define i1 @test_two_return_attribute_ranges_one_in_call() {
+; CHECK-LABEL: @test_two_return_attribute_ranges_one_in_call(
+; CHECK-NEXT:    [[VAL1:%.*]] = call range(i32 1, 6) i32 @create_range1()
+; CHECK-NEXT:    [[ARG1:%.*]] = call i32 @create_range2()
+; CHECK-NEXT:    ret i1 false
+;
+  %val1 = call range(i32 1, 6) i32 @create_range1()
+  %val2 = call i32 @create_range2()
+  %rval = icmp ult i32 %val2, %val1
+  ret i1 %rval
+}
+
+; Values' ranges do not overlap each other, so it can simplified to false.
+define i1 @test_two_return_attribute_ranges() {
+; CHECK-LABEL: @test_two_return_attribute_ranges(
+; CHECK-NEXT:    [[VAL1:%.*]] = call i32 @create_range3()
+; CHECK-NEXT:    [[ARG1:%.*]] = call i32 @create_range2()
+; CHECK-NEXT:    ret i1 false
+;
+  %val1 = call i32 @create_range3()
+  %val2 = call i32 @create_range2()
+  %rval = icmp ult i32 %val2, %val1
+  ret i1 %rval
+}
+
+; Values' ranges do not overlap each other, so it can simplified to false.
+define i1 @test_one_return_argument_and_one_argument_range(i32 range(i32 8, 16) %arg1) {
+; CHECK-LABEL: @test_one_return_argument_and_one_argument_range(
+; CHECK-NEXT:    [[VAL1:%.*]] = call i32 @create_range3()
+; CHECK-NEXT:    ret i1 false
+;
+  %val1 = call i32 @create_range3()
+  %rval = icmp ult i32 %arg1, %val1
+  ret i1 %rval
+}
+
+; Values' ranges do not overlap each other, so it can simplified to false.
+define i1 @test_one_range_and_one_return_argument(ptr nocapture readonly %arg1) {
+; CHECK-LABEL: @test_one_range_and_one_return_argument(
+; CHECK-NEXT:    [[VAL1:%.*]] = call i32 @create_range3()
+; CHECK-NEXT:    ret i1 false
+;
+  %val1 = call i32 @create_range3()
+  %val2 = load i32, ptr %arg1, !range !6
+  %rval = icmp ult i32 %val2, %val1
+  ret i1 %rval
+}
+
 define i1 @ugt_zext(i1 %b, i8 %x) {
 ; CHECK-LABEL: @ugt_zext(
 ; CHECK-NEXT:    [[TMP1:%.*]] = icmp eq i8 [[X:%.*]], 0