[llvm] [LV] Compute value of escaped induction based on the computed end value. (PR #110576)

[via llvm-commits]

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@@ -2747,17 +2747,24 @@ void InnerLoopVectorizer::fixupIVUsers(PHINode *OrigPhi,
       if (isa_and_nonnull<FPMathOperator>(II.getInductionBinOp()))
         B.setFastMathFlags(II.getInductionBinOp()->getFastMathFlags());
 
-      Value *CountMinusOne = B.CreateSub(
-          VectorTripCount, ConstantInt::get(VectorTripCount->getType(), 1));
-      CountMinusOne->setName("cmo");
-
       VPValue *StepVPV = Plan.getSCEVExpansion(II.getStep());
       assert(StepVPV && "step must have been expanded during VPlan execution");
       Value *Step = StepVPV->isLiveIn() ? StepVPV->getLiveInIRValue()
                                         : State.get(StepVPV, VPLane(0));
-      Value *Escape =
-          emitTransformedIndex(B, CountMinusOne, II.getStartValue(), Step,
-                               II.getKind(), II.getInductionBinOp());
+      Value *Escape = nullptr;
+      if (EndValue->getType()->isIntegerTy())
+        Escape = B.CreateSub(EndValue, Step);
+      else if (EndValue->getType()->isPointerTy())
+        Escape = B.CreatePtrAdd(EndValue, B.CreateNeg(Step));
+      else if (EndValue->getType()->isFloatingPointTy()) {
+        Escape = B.CreateBinOp(II.getInductionBinOp()->getOpcode() ==
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ayalz wrote:

nit (post-commit): is there a more consistent way to handle these three cases rather than creating sub for integer (assuming original opcode is add?), negating step for pointer, and reversing the opcode for floating point? Would negating the step work for all, with their original opcode?

https://github.com/llvm/llvm-project/pull/110576