[llvm] [LoopVectorize] Teach LoopVectorizationLegality about more early exits (PR #107004)

[David Sherwood via llvm-commits]

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@@ -377,6 +377,24 @@ class LoopVectorizationLegality {
     return LAI->getDepChecker().getMaxSafeVectorWidthInBits();
   }
 
+  /// Returns true if the loop has a speculative early exit, i.e. an
+  /// uncountable exit that isn't the latch block.
+  bool hasSpeculativeEarlyExit() const { return HasSpeculativeEarlyExit; }
+
+  /// Returns the speculative early exiting block.
+  BasicBlock *getSpeculativeEarlyExitingBlock() const {
+    assert(getUncountableExitingBlocks().size() == 1 &&
+           "Expected only a single uncountable exiting block");
+    return getUncountableExitingBlocks()[0];
+  }
+
+  /// Returns the destination of a speculative early exiting block.
+  BasicBlock *getSpeculativeEarlyExitBlock() const {
+    assert(getUncountableExitBlocks().size() == 1 &&
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david-arm wrote:

I could do that, and would be happy to do so if people prefer. I wrote it this way because in future I thought it's possible we may support multiple early exits. @paulwalker-arm @huntergr-arm any preference?

https://github.com/llvm/llvm-project/pull/107004