[llvm] c8e0672 - [Loops] Use forgetLcssaPhiWithNewPredecessor() in more places

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2024-09-23T09:54:28+02:00
New Revision: c8e0672864abf6fb624ddde5d6a1775d8634213a

URL: https://github.com/llvm/llvm-project/commit/c8e0672864abf6fb624ddde5d6a1775d8634213a
DIFF: https://github.com/llvm/llvm-project/commit/c8e0672864abf6fb624ddde5d6a1775d8634213a.diff

LOG: [Loops] Use forgetLcssaPhiWithNewPredecessor() in more places

Use the more aggressive invalidation method in a number of places
that add incoming values to lcssa phi nodes. It is likely that
it's possible to construct cases with incorrect SCEV preservation
similar to https://github.com/llvm/llvm-project/issues/109333 for
these.

Added: 
    

Modified: 
    llvm/lib/Transforms/Utils/LoopConstrainer.cpp
    llvm/lib/Transforms/Utils/LoopUnroll.cpp
    llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
    llvm/lib/Transforms/Utils/LoopVersioning.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Utils/LoopConstrainer.cpp b/llvm/lib/Transforms/Utils/LoopConstrainer.cpp
index 4ae2baca327c7a..8f103153059e82 100644
--- a/llvm/lib/Transforms/Utils/LoopConstrainer.cpp
+++ b/llvm/lib/Transforms/Utils/LoopConstrainer.cpp
@@ -510,7 +510,7 @@ void LoopConstrainer::cloneLoop(LoopConstrainer::ClonedLoop &Result,
       for (PHINode &PN : SBB->phis()) {
         Value *OldIncoming = PN.getIncomingValueForBlock(OriginalBB);
         PN.addIncoming(GetClonedValue(OldIncoming), ClonedBB);
-        SE.forgetValue(&PN);
+        SE.forgetLcssaPhiWithNewPredecessor(&OriginalLoop, &PN);
       }
     }
   }

diff  --git a/llvm/lib/Transforms/Utils/LoopUnroll.cpp b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
index a0406111ecbf3b..b90addcef69e6e 100644
--- a/llvm/lib/Transforms/Utils/LoopUnroll.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
@@ -770,7 +770,7 @@ llvm::UnrollLoop(Loop *L, UnrollLoopOptions ULO, LoopInfo *LI,
           if (It != LastValueMap.end())
             Incoming = It->second;
           PHI.addIncoming(Incoming, New);
-          SE->forgetValue(&PHI);
+          SE->forgetLcssaPhiWithNewPredecessor(L, &PHI);
         }
       }
       // Keep track of new headers and latches as we create them, so that

diff  --git a/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp b/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
index 2d74b2b8d1d2fd..5e2c15344e0d03 100644
--- a/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
@@ -146,7 +146,7 @@ static void ConnectProlog(Loop *L, Value *BECount, unsigned Count,
         PN.setIncomingValueForBlock(NewPreHeader, NewPN);
       else
         PN.addIncoming(NewPN, PrologExit);
-      SE.forgetValue(&PN);
+      SE.forgetLcssaPhiWithNewPredecessor(L, &PN);
     }
   }
 

diff  --git a/llvm/lib/Transforms/Utils/LoopVersioning.cpp b/llvm/lib/Transforms/Utils/LoopVersioning.cpp
index af2ed6240f7220..8f8c40a4e73be1 100644
--- a/llvm/lib/Transforms/Utils/LoopVersioning.cpp
+++ b/llvm/lib/Transforms/Utils/LoopVersioning.cpp
@@ -137,7 +137,7 @@ void LoopVersioning::addPHINodes(
     // original loop.
     for (auto I = PHIBlock->begin(); (PN = dyn_cast<PHINode>(I)); ++I) {
       if (PN->getIncomingValue(0) == Inst) {
-        SE->forgetValue(PN);
+        SE->forgetLcssaPhiWithNewPredecessor(VersionedLoop, PN);
         break;
       }
     }