[llvm] [LV] Vectorize uncountable early exit store loops with combined conditions (PR #205109)

[Florian Hahn via llvm-commits]

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@@ -1780,26 +1804,52 @@ bool LoopVectorizationLegality::canUncountableExitConditionLoadBeMoved(
   auto *Br = cast<CondBrInst>(ExitingBlock->getTerminator());
 
   using namespace llvm::PatternMatch;
-  Instruction *L = nullptr;
-  Value *Ptr = nullptr;
-  Value *R = nullptr;
-  // The exit-condition load can appear on either side of the icmp.
+  using namespace llvm::SCEVPatternMatch;
+  Value *Ptr, *L, *R, *IVInc = nullptr;
+  // We want to match either an uncounted condition (loaded value compared
+  // against a loop invariant value) or the combination (via logical or) of
+  // an uncounted condition with a counted condition (integer comparison of
+  // an induction variable for which we can identify an add recurrence within
+  // this loop).
+  auto m_Uncounted = [](auto &&Ptr, auto &&L, auto &&R) {
+    return m_OneUse(
+        m_c_ICmp(m_OneUse(m_Value(L, m_Load(m_Value(Ptr)))), m_Value(R)));
+  };
+  auto m_Counted = [](auto &&IVInc) {
+    return m_c_ICmp(m_Value(IVInc, m_Add(m_Value(), m_Value())), m_Value());
+  };
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fhahn wrote:

this is duplicated in multiple places, could we share the logic somehow so we have a single place to update?

Also, around line 1684 we allow any value as other condition, while here and below i t must a compare of a load

https://github.com/llvm/llvm-project/pull/205109