[llvm] [APInt] Added APInt::clearBits() method (PR #137098)

[Liam Semeria via llvm-commits]

================
@@ -2520,6 +2520,62 @@ TEST(APIntTest, setAllBits) {
   EXPECT_EQ(128u, i128.popcount());
 }
 
+TEST(APIntTest, clearBits) {
+  APInt i32 = APInt::getAllOnes(32);
+  i32.clearBits(1, 3);
+  EXPECT_EQ(1u, i32.countr_one());
+  EXPECT_EQ(0u, i32.countr_zero());
+  EXPECT_EQ(32u, i32.getActiveBits());
+  EXPECT_EQ(0u, i32.countl_zero());
+  EXPECT_EQ(29u, i32.countl_one());
+  EXPECT_EQ(30u, i32.popcount());
+
+  i32.clearBits(15, 15);
+  EXPECT_EQ(1u, i32.countr_one());
+  EXPECT_EQ(0u, i32.countr_zero());
+  EXPECT_EQ(32u, i32.getActiveBits());
+  EXPECT_EQ(0u, i32.countl_zero());
+  EXPECT_EQ(29u, i32.countl_one());
+  EXPECT_EQ(30u, i32.popcount());
+
+  i32.clearBits(28, 31);
+  EXPECT_EQ(1u, i32.countr_one());
+  EXPECT_EQ(0u, i32.countr_zero());
+  EXPECT_EQ(32u, i32.getActiveBits());
+  EXPECT_EQ(0u, i32.countl_zero());
+  EXPECT_EQ(1u, i32.countl_one());
+  EXPECT_EQ(27u, i32.popcount());
+  EXPECT_EQ(static_cast<uint64_t>((1 << 31) | ((~0u >> 4) & (~0u << 3)) | 1),
+            i32.getZExtValue());
+
+  APInt i256 = APInt::getAllOnes(256);
----------------
liamsemeria wrote:

Yeah I'll add that test case. 
Should I search for "DemandedSrcElts.insertBits(APInt::getZero(NumSubElts), Idx);" in all files or just in specific ones?

https://github.com/llvm/llvm-project/pull/137098