[llvm] [PatternMatching] Add generic API for matching constants using custom conditions (PR #85676)

[Nikita Popov via llvm-commits]

================
@@ -611,6 +611,212 @@ TEST_F(PatternMatchTest, BitCast) {
   EXPECT_FALSE(m_ElementWiseBitCast(m_Value()).match(NXV2I64ToNXV4I32));
 }
 
+TEST_F(PatternMatchTest, CustomCheckFn) {
+  APInt I0(64, 0);
+  APInt I1(64, 0);
+
+  auto CheckIsZeroI = [](const APInt &C) { return C.isZero(); };
+  auto CheckIsEqI1 = [&I1](const APInt &C) { return C.eq(I1); };
+  auto CheckIsNeI1 = [&I1](const APInt &C) { return !C.eq(I1); };
+
+  custom_checkfn<APInt> CustomCheckZeroI;
+  CustomCheckZeroI.CheckFn = CheckIsZeroI;
+  custom_checkfn<APInt> CustomCheckEqI1;
+  CustomCheckEqI1.CheckFn = CheckIsEqI1;
+  custom_checkfn<APInt> CustomCheckNeI1;
+  CustomCheckNeI1.CheckFn = CheckIsNeI1;
+
+  EXPECT_TRUE(CustomCheckZeroI.isValue(I0));
+  EXPECT_TRUE(CustomCheckEqI1.isValue(I0));
+  EXPECT_FALSE(CustomCheckNeI1.isValue(I0));
+
+  I0.setBit(0);
+
+  EXPECT_FALSE(CustomCheckZeroI.isValue(I0));
+  EXPECT_FALSE(CustomCheckEqI1.isValue(I0));
+  EXPECT_TRUE(CustomCheckNeI1.isValue(I0));
+
+  I1.setBit(0);
+
+  EXPECT_FALSE(CustomCheckZeroI.isValue(I0));
+  EXPECT_TRUE(CustomCheckEqI1.isValue(I0));
+  EXPECT_FALSE(CustomCheckNeI1.isValue(I0));
+
+  APFloat F0(0.0);
+  APFloat F1(0.0);
+
+  auto CheckIsZeroF = [](const APFloat &C) { return C.isZero(); };
+  auto CheckIsEqF1 = [&F1](const APFloat &C) {
+    return C.bitcastToAPInt().eq(F1.bitcastToAPInt());
+  };
+  auto CheckIsNeF1 = [&F1](const APFloat &C) {
+    return !C.bitcastToAPInt().eq(F1.bitcastToAPInt());
+  };
+
+  custom_checkfn<APFloat> CustomCheckZeroF;
+  CustomCheckZeroF.CheckFn = CheckIsZeroF;
+  custom_checkfn<APFloat> CustomCheckEqF1;
+  CustomCheckEqF1.CheckFn = CheckIsEqF1;
+  custom_checkfn<APFloat> CustomCheckNeF1;
+  CustomCheckNeF1.CheckFn = CheckIsNeF1;
+
+  EXPECT_TRUE(CustomCheckZeroF.isValue(F0));
+  EXPECT_TRUE(CustomCheckEqF1.isValue(F0));
+  EXPECT_FALSE(CustomCheckNeF1.isValue(F0));
+
+  F0 = -F0;
+
+  EXPECT_TRUE(CustomCheckZeroF.isValue(F0));
+  EXPECT_FALSE(CustomCheckEqF1.isValue(F0));
+  EXPECT_TRUE(CustomCheckNeF1.isValue(F0));
+
+  F0 = -F0;
+
+  EXPECT_TRUE(CustomCheckZeroF.isValue(F0));
+  EXPECT_TRUE(CustomCheckEqF1.isValue(F0));
+  EXPECT_FALSE(CustomCheckNeF1.isValue(F0));
+
+  F0 = F0 + APFloat(1.0);
+
+  EXPECT_FALSE(CustomCheckZeroF.isValue(F0));
+  EXPECT_FALSE(CustomCheckEqF1.isValue(F0));
+  EXPECT_TRUE(CustomCheckNeF1.isValue(F0));
+
+  F1 = F1 + APFloat(1.0);
+
+  EXPECT_FALSE(CustomCheckZeroF.isValue(F0));
+  EXPECT_TRUE(CustomCheckEqF1.isValue(F0));
+  EXPECT_FALSE(CustomCheckNeF1.isValue(F0));
+}
----------------
nikic wrote:

Hm, I'd consider custom_checkfn to be a PatternMatch implementation detail -- do we really need unit tests for it if you already have tests for m_CheckedInt below?

https://github.com/llvm/llvm-project/pull/85676