[ConstantFPRange] Add getWithout[NaN|Inf] (#162696)

This patch adds getWithoutNaN/getWithoutInf. We will apply nnan/ninf
flags to the range of operands/results for a more precise range.

Author: dtcxzyw

llvm/include/llvm/IR/ConstantFPRange.h

@@ -206,6 +206,16 @@ class [[nodiscard]] ConstantFPRange {
 
   /// Calculate range of negated values.
   LLVM_ABI ConstantFPRange negate() const;
+
+  /// Get the range without NaNs. It is useful when we apply nnan flag to range
+  /// of operands/results.
+  ConstantFPRange getWithoutNaN() const {
+    return ConstantFPRange(Lower, Upper, false, false);
+  }
+
+  /// Get the range without infinities. It is useful when we apply ninf flag to
+  /// range of operands/results.
+  LLVM_ABI ConstantFPRange getWithoutInf() const;
 };
 
 inline raw_ostream &operator<<(raw_ostream &OS, const ConstantFPRange &CR) {

llvm/lib/IR/ConstantFPRange.cpp

@@ -411,3 +411,17 @@ ConstantFPRange ConstantFPRange::abs() const {
 ConstantFPRange ConstantFPRange::negate() const {
   return ConstantFPRange(-Upper, -Lower, MayBeQNaN, MayBeSNaN);
 }
+
+ConstantFPRange ConstantFPRange::getWithoutInf() const {
+  if (isNaNOnly())
+    return *this;
+  APFloat NewLower = Lower;
+  APFloat NewUpper = Upper;
+  if (Lower.isNegInfinity())
+    NewLower = APFloat::getLargest(getSemantics(), /*Negative=*/true);
+  if (Upper.isPosInfinity())
+    NewUpper = APFloat::getLargest(getSemantics(), /*Negative=*/false);
+  canonicalizeRange(NewLower, NewUpper);
+  return ConstantFPRange(std::move(NewLower), std::move(NewUpper), MayBeQNaN,
+                         MayBeSNaN);
+}

llvm/unittests/IR/ConstantFPRangeTest.cpp

@@ -802,4 +802,20 @@ TEST_F(ConstantFPRangeTest, negate) {
             ConstantFPRange::getNonNaN(APFloat(-2.0), APFloat(3.0)));
 }
 
+TEST_F(ConstantFPRangeTest, getWithout) {
+  EXPECT_EQ(Full.getWithoutNaN(), ConstantFPRange::getNonNaN(Sem));
+  EXPECT_EQ(NaN.getWithoutNaN(), Empty);
+
+  EXPECT_EQ(NaN.getWithoutInf(), NaN);
+  EXPECT_EQ(PosInf.getWithoutInf(), Empty);
+  EXPECT_EQ(NegInf.getWithoutInf(), Empty);
+  EXPECT_EQ(ConstantFPRange::getNonNaN(Sem).getWithoutInf(), Finite);
+  EXPECT_EQ(Zero.getWithoutInf(), Zero);
+  EXPECT_EQ(ConstantFPRange::getNonNaN(APFloat::getInf(Sem, /*Negative=*/true),
+                                       APFloat(3.0))
+                .getWithoutInf(),
+            ConstantFPRange::getNonNaN(
+                APFloat::getLargest(Sem, /*Negative=*/true), APFloat(3.0)));
+}
+
 } // anonymous namespace