[llvm] [LV] Use frozen start value for FindLastIV if needed. (PR #132691)

[David Sherwood via llvm-commits]

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@@ -939,6 +946,7 @@ bool VPInstruction::onlyFirstLaneUsed(const VPValue *Op) const {
   case Instruction::ICmp:
   case Instruction::Select:
   case Instruction::Or:
+  case Instruction::Freeze:
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david-arm wrote:

We should probably also add this opcode to `VPInstruction::opcodeMayReadOrWriteFromMemory` and return `false`.

https://github.com/llvm/llvm-project/pull/132691