[llvm] [VPlan] Replace VPRegionBlock with explicit CFG before execute (NFCI). (PR #117506)

[via llvm-commits]

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@@ -1360,16 +1384,16 @@ void VPlanPrinter::dumpRegion(const VPRegionBlock *Region) {
 
 #endif
 
-/// Returns true if there is a vector loop region and \p VPV is defined in a
-/// loop region.
-static bool isDefinedInsideLoopRegions(const VPValue *VPV) {
-  const VPRecipeBase *DefR = VPV->getDefiningRecipe();
-  return DefR && (!DefR->getParent()->getPlan()->getVectorLoopRegion() ||
-                  DefR->getParent()->getEnclosingLoopRegion());
-}
-
 bool VPValue::isDefinedOutsideLoopRegions() const {
-  return !isDefinedInsideLoopRegions(this);
+  auto *DefR = getDefiningRecipe();
+  if (!DefR)
+    return true;
+
+  const VPBasicBlock *DefVPBB = DefR->getParent();
+  auto *Plan = DefVPBB->getPlan();
+  if (Plan->getVectorLoopRegion())
+    return !DefR->getParent()->getEnclosingLoopRegion();
+  return DefVPBB == Plan->getEntry();
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ayalz wrote:

The only out-of-loop place that values can be defined in when regions are gone - is in Plan's entry block?

https://github.com/llvm/llvm-project/pull/117506