[llvm] [LoopVectorize] Add support for vectorisation of simple early exit loops (PR #88385)

[David Sherwood via llvm-commits]

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@@ -181,6 +181,16 @@ static cl::opt<bool> EnableEpilogueVectorization(
     "enable-epilogue-vectorization", cl::init(true), cl::Hidden,
     cl::desc("Enable vectorization of epilogue loops."));
 
+static cl::opt<bool> EnableEarlyExitVectorization(
+    "enable-early-exit-vectorization", cl::init(false), cl::Hidden,
+    cl::desc("Enable vectorization of early exit loops."));
+
+static cl::opt<bool> AssumeNoMemFault(
+    "vectorizer-no-mem-fault", cl::init(false), cl::Hidden,
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david-arm wrote:

The intention really was for general testing, i.e. running the LLVM test suite, SPEC2017, etc. and making sure that tests/benchmarks are behaving correctly. With the flag enabled over 2000 loops in the LLVM test suite suddenly start vectorising. Well-behaved programs shouldn't fault if they've specified a trip count, but obviously it's completely unsafe to enable this in general. It was for convenience really - I could remove the flag, but it just means every time we want to test auto-vectorisation with wider coverage we have to hack the vectoriser every time manually.

https://github.com/llvm/llvm-project/pull/88385