[LSR] Strip dead code (NFC)

[artagnon]

Nested AddRec is already rejected by the handling in pushSCEV().

[llvmbot]

@llvm/pr-subscribers-llvm-transforms

Author: Ramkumar Ramachandra (artagnon)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/146109.diff

1 Files Affected:

• (modified) llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp (-9)

diff --git a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 4ba69034d6448..c914c3eb19a05 100644
--- a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -6479,10 +6479,6 @@ struct SCEVDbgValueBuilder {
   /// Chain (non-affine) SCEVs are not supported.
   bool SCEVToValueExpr(const llvm::SCEVAddRecExpr &SAR, ScalarEvolution &SE) {
     assert(SAR.isAffine() && "Expected affine SCEV");
-    // TODO: Is this check needed?
-    if (isa<SCEVAddRecExpr>(SAR.getStart()))
-      return false;
-
     const SCEV *Start = SAR.getStart();
     const SCEV *Stride = SAR.getStepRecurrence(SE);
 
@@ -6550,11 +6546,6 @@ struct SCEVDbgValueBuilder {
   bool SCEVToIterCountExpr(const llvm::SCEVAddRecExpr &SAR,
                            ScalarEvolution &SE) {
     assert(SAR.isAffine() && "Expected affine SCEV");
-    if (isa<SCEVAddRecExpr>(SAR.getStart())) {
-      LLVM_DEBUG(dbgs() << "scev-salvage: IV SCEV. Unsupported nested AddRec: "
-                        << SAR << '\n');
-      return false;
-    }
     const SCEV *Start = SAR.getStart();
     const SCEV *Stride = SAR.getStepRecurrence(SE);
 

[artagnon]

Gentle ping.

[nikic]

LGTM, but please add a PR description. Nested addrec will handled (i.e. rejected) by pushSCEV().