[llvm] [AArch64] Add MATCH loops to LoopIdiomVectorizePass (PR #101976)

[Ricardo Jesus via llvm-commits]

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@@ -939,3 +988,361 @@ void LoopIdiomVectorize::transformByteCompare(GetElementPtrInst *GEPA,
       report_fatal_error("Loops must remain in LCSSA form!");
   }
 }
+
+bool LoopIdiomVectorize::recognizeFindFirstByte() {
+  // Currently the transformation only works on scalable vector types, although
+  // there is no fundamental reason why it cannot be made to work for fixed
+  // vectors too.
+  if (!TTI->supportsScalableVectors() || DisableFindFirstByte)
+    return false;
+
+  // Define some constants we need throughout.
+  BasicBlock *Header = CurLoop->getHeader();
+  LLVMContext &Ctx = Header->getContext();
+
+  // We are expecting the blocks below. For now, we will bail out for almost
+  // anything other than this.
+  //
+  // Header:
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rj-jesus wrote:

Thanks, done.

https://github.com/llvm/llvm-project/pull/101976