[ConstantRange] Handle `Intrinsic::ctpop` (#68310)

This patch adds support for `Intrinsic::ctpop` in ConstantRange. It
calculates the range in O(1) with the LCP-based method.

Migrated from https://reviews.llvm.org/D153505.

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/unittests/IR/ConstantRangeTest.cpp b/llvm/unittests/IR/ConstantRangeTest.cpp
index 1cb358a..12facfb 100644
--- a/llvm/unittests/IR/ConstantRangeTest.cpp
+++ b/llvm/unittests/IR/ConstantRangeTest.cpp
@@ -2438,6 +2438,12 @@ TEST_F(ConstantRangeTest, Ctlz) {
       });
 }
 
+TEST_F(ConstantRangeTest, Ctpop) {
+  TestUnaryOpExhaustive(
+      [](const ConstantRange &CR) { return CR.ctpop(); },
+      [](const APInt &N) { return APInt(N.getBitWidth(), N.popcount()); });
+}
+
 TEST_F(ConstantRangeTest, castOps) {
   ConstantRange A(APInt(16, 66), APInt(16, 128));
   ConstantRange FpToI8 = A.castOp(Instruction::FPToSI, 8);