[llvm] Add ConstantRangeList::unionWith() and ::intersectWith() (PR #96547)

[Arthur Eubanks via llvm-commits]

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@@ -94,4 +94,122 @@ TEST_F(ConstantRangeListTest, Insert) {
   EXPECT_TRUE(CRL == Expected);
 }
 
+ConstantRangeList GetCRL(const SmallVector<std::pair<APInt, APInt>, 2> &Pairs) {
+  SmallVector<ConstantRange, 2> Ranges;
+  for (auto &[Start, End] : Pairs)
+    Ranges.push_back(ConstantRange(Start, End));
+  return ConstantRangeList(Ranges);
+}
+
+TEST_F(ConstantRangeListTest, Union) {
+  APInt AP0 = APInt(64, 0, /*isSigned=*/true);
+  APInt AP2 = APInt(64, 2, /*isSigned=*/true);
+  APInt AP4 = APInt(64, 4, /*isSigned=*/true);
+  APInt AP8 = APInt(64, 8, /*isSigned=*/true);
+  APInt AP10 = APInt(64, 10, /*isSigned=*/true);
+  APInt AP11 = APInt(64, 11, /*isSigned=*/true);
+  APInt AP12 = APInt(64, 12, /*isSigned=*/true);
+  ConstantRangeList CRL = GetCRL({{AP0, AP4}, {AP8, AP12}});
+
+  // Union with a subset.
+  ConstantRangeList Empty;
+  EXPECT_TRUE(CRL.unionWith(Empty) == CRL);
+  EXPECT_TRUE(Empty.unionWith(CRL) == CRL);
+
+  EXPECT_TRUE(CRL.unionWith(GetCRL({{AP0, AP2}})) == CRL);
+  EXPECT_TRUE(CRL.unionWith(GetCRL({{AP10, AP12}})) == CRL);
+
+  EXPECT_TRUE(CRL.unionWith(GetCRL({{AP0, AP2}, {AP8, AP10}})) == CRL);
+  EXPECT_TRUE(CRL.unionWith(GetCRL({{AP0, AP2}, {AP10, AP12}})) == CRL);
+  EXPECT_TRUE(CRL.unionWith(GetCRL({{AP2, AP4}, {AP8, AP10}})) == CRL);
+  EXPECT_TRUE(CRL.unionWith(GetCRL({{AP2, AP4}, {AP10, AP12}})) == CRL);
+
+  EXPECT_TRUE(CRL.unionWith(GetCRL({{AP0, AP4}, {AP8, AP10}, {AP11, AP12}})) ==
+              CRL);
+
+  EXPECT_TRUE(CRL.unionWith(CRL) == CRL);
+
+  // Union with new ranges.
+  APInt APN4 = APInt(64, -4, /*isSigned=*/true);
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aeubanks wrote:

group this with APInts above

https://github.com/llvm/llvm-project/pull/96547