[PATCH] D104631: [LoopVersioning] add function to create versioned loop with plain runtime check

[Yueh-Ting Chen via Phabricator via llvm-commits]

eopXD updated this revision to Diff 354655.
eopXD added a comment.

Preserve information inside `versionLoop` and add helper functions to get them.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D104631/new/

https://reviews.llvm.org/D104631

Files:
  llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp


Index: llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
+++ llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
@@ -161,10 +161,11 @@
 
 class LoopIdiomRecognize {
   Loop *CurLoop = nullptr;
-  LoopNest *LN;
+  LoopNest *LN = nullptr;
   Loop *TopLoop = nullptr;
   Loop *FallBackLoop = nullptr;
   BasicBlock *RuntimeCheckBB = nullptr;
+  BranchInst *RuntimeCheckBI = nullptr;
   AliasAnalysis *AA;
   DominatorTree *DT;
   LoopInfo *LI;
@@ -461,9 +462,7 @@
   // the RuntimeCheckBB. Conditions are stored when:
   //   - detect runtime store size in StridedStore (SizeAddrSpacePairList)
   if (Changed && isTopLoopVersioned()) {
-    // Get the branch instruction in the runtime check basic block.
-    BranchInst *BI = dyn_cast<BranchInst>(RuntimeCheckBB->getTerminator());
-    assert(BI && "Expects a BranchInst");
+    assert(RuntimeCheckBI && "should be fetched when calling versionTopLoop()");
 
     // Create conditional branch instructions with conditions:
     //   - Store size overflow half of the width of the pointer
@@ -472,20 +471,18 @@
     LLVMContext &Context = TopLoop->getHeader()->getContext();
     Value *Cond = ConstantInt::getFalse(Context);
 
-    IRBuilder<> Builder(BI);
+    IRBuilder<> Builder(RuntimeCheckBI);
     for (auto Pair : *SizeAddrSpacePairList) {
       const SCEV *Ev = Pair.first;
       unsigned AddrSpace = Pair.second;
       Value *NewCond0 =
-          generateOverflowPredicate(Ev, AddrSpace, BI, DL, SE, Builder);
-      Value *NewCond1 = generateSltZeroPredicate(Ev, BI, DL, SE, Builder);
+          generateOverflowPredicate(Ev, AddrSpace, RuntimeCheckBI, DL, SE, Builder);
+      Value *NewCond1 = generateSltZeroPredicate(Ev, RuntimeCheckBI, DL, SE, Builder);
       Cond = Builder.CreateOr(Cond, NewCond0);
       Cond = Builder.CreateOr(Cond, NewCond1);
     }
 
-    BranchInst::Create(FallBackLoop->getLoopPreheader(),
-                       LN->getOutermostLoop().getLoopPreheader(), Cond, BI);
-    deleteDeadInstruction(BI);
+    RuntimeCheckBI->setCondition(Cond);
   }
 
   return Changed;
@@ -1689,9 +1686,10 @@
   LoopVersioning LV(LAI, LAI.getRuntimePointerChecking()->getChecks(), TopLoop,
                     LI, DT, SE);
 
-  LV.versionLoopWithPlainRuntimeCheck();
+  LV.versionLoop();
 
   RuntimeCheckBB = LV.getRuntimeCheckBB();
+  RuntimeCheckBI = LV.getRuntimeCheckBI();
   FallBackLoop = LV.getNonVersionedLoop();
 }
 


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