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

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-ir

Author: Yingwei Zheng (dtcxzyw)

<details>
<summary>Changes</summary>

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


---
Full diff: https://github.com/llvm/llvm-project/pull/162696.diff


3 Files Affected:

- (modified) llvm/include/llvm/IR/ConstantFPRange.h (+10) 
- (modified) llvm/lib/IR/ConstantFPRange.cpp (+14) 
- (modified) llvm/unittests/IR/ConstantFPRangeTest.cpp (+16) 


``````````diff
diff --git a/llvm/include/llvm/IR/ConstantFPRange.h b/llvm/include/llvm/IR/ConstantFPRange.h
index 930c6f98c033f..8d4fe349c20eb 100644
--- a/llvm/include/llvm/IR/ConstantFPRange.h
+++ b/llvm/include/llvm/IR/ConstantFPRange.h
@@ -200,6 +200,16 @@ class [[nodiscard]] ConstantFPRange {
   /// with another range.  The resultant range is guaranteed to include the
   /// elements of both sets, but may contain more.
   LLVM_ABI ConstantFPRange unionWith(const ConstantFPRange &CR) 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) {
diff --git a/llvm/lib/IR/ConstantFPRange.cpp b/llvm/lib/IR/ConstantFPRange.cpp
index 7509188128524..6a8260802ca12 100644
--- a/llvm/lib/IR/ConstantFPRange.cpp
+++ b/llvm/lib/IR/ConstantFPRange.cpp
@@ -391,3 +391,17 @@ ConstantFPRange ConstantFPRange::unionWith(const ConstantFPRange &CR) const {
   return ConstantFPRange(minnum(Lower, CR.Lower), maxnum(Upper, CR.Upper),
                          MayBeQNaN | CR.MayBeQNaN, MayBeSNaN | CR.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);
+}
diff --git a/llvm/unittests/IR/ConstantFPRangeTest.cpp b/llvm/unittests/IR/ConstantFPRangeTest.cpp
index 255f62d77b748..620d7ae8b35de 100644
--- a/llvm/unittests/IR/ConstantFPRangeTest.cpp
+++ b/llvm/unittests/IR/ConstantFPRangeTest.cpp
@@ -767,4 +767,20 @@ TEST_F(ConstantFPRangeTest, makeExactFCmpRegion) {
   }
 }
 
+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

``````````

</details>


https://github.com/llvm/llvm-project/pull/162696