[llvm] [Support] Add KnownBits::abds signed absolute difference and rename absdiff -> abdu (PR #84897)

[Jay Foad via llvm-commits]

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@@ -294,18 +294,18 @@ TEST(KnownBitsTest, SignBitUnknown) {
   EXPECT_TRUE(Known.isSignUnknown());
 }
 
-TEST(KnownBitsTest, AbsDiffSpecialCase) {
-  // There are 2 implementation of absdiff - both are currently needed to cover
+TEST(KnownBitsTest, ABDUSpecialCase) {
+  // There are 2 implementation of abdu - both are currently needed to cover
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jayfoad wrote:

"implementations"

https://github.com/llvm/llvm-project/pull/84897