From 706b4fc47bbc608932d3b491ae19a3b9cde9497b Mon Sep 17 00:00:00 2001
From: Dimitry Andric <dim@FreeBSD.org>
Date: Fri, 17 Jan 2020 20:45:01 +0000
Subject: Vendor import of llvm-project master e26a78e70, the last commit
 before the llvmorg-11-init tag, from which release/10.x was branched.

---
 llvm/lib/Transforms/Utils/LCSSA.cpp | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

(limited to 'llvm/lib/Transforms/Utils/LCSSA.cpp')

diff --git a/llvm/lib/Transforms/Utils/LCSSA.cpp b/llvm/lib/Transforms/Utils/LCSSA.cpp
index 29e7c5260f46..5746d69260d5 100644
--- a/llvm/lib/Transforms/Utils/LCSSA.cpp
+++ b/llvm/lib/Transforms/Utils/LCSSA.cpp
@@ -43,7 +43,9 @@
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/PredIteratorCache.h"
+#include "llvm/InitializePasses.h"
 #include "llvm/Pass.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Transforms/Utils.h"
 #include "llvm/Transforms/Utils/Local.h"
 #include "llvm/Transforms/Utils/LoopUtils.h"
@@ -74,7 +76,8 @@ static bool isExitBlock(BasicBlock *BB,
 /// that are outside the current loop.  If so, insert LCSSA PHI nodes and
 /// rewrite the uses.
 bool llvm::formLCSSAForInstructions(SmallVectorImpl<Instruction *> &Worklist,
-                                    DominatorTree &DT, LoopInfo &LI) {
+                                    DominatorTree &DT, LoopInfo &LI,
+                                    ScalarEvolution *SE) {
   SmallVector<Use *, 16> UsesToRewrite;
   SmallSetVector<PHINode *, 16> PHIsToRemove;
   PredIteratorCache PredCache;
@@ -134,6 +137,11 @@ bool llvm::formLCSSAForInstructions(SmallVectorImpl<Instruction *> &Worklist,
     SSAUpdater SSAUpdate(&InsertedPHIs);
     SSAUpdate.Initialize(I->getType(), I->getName());
 
+    // Force re-computation of I, as some users now need to use the new PHI
+    // node.
+    if (SE)
+      SE->forgetValue(I);
+
     // Insert the LCSSA phi's into all of the exit blocks dominated by the
     // value, and add them to the Phi's map.
     for (BasicBlock *ExitBB : ExitBlocks) {
@@ -192,9 +200,6 @@ bool llvm::formLCSSAForInstructions(SmallVectorImpl<Instruction *> &Worklist,
         UserBB = PN->getIncomingBlock(*UseToRewrite);
 
       if (isa<PHINode>(UserBB->begin()) && isExitBlock(UserBB, ExitBlocks)) {
-        // Tell the VHs that the uses changed. This updates SCEV's caches.
-        if (UseToRewrite->get()->hasValueHandle())
-          ValueHandleBase::ValueIsRAUWd(*UseToRewrite, &UserBB->front());
         UseToRewrite->set(&UserBB->front());
         continue;
       }
@@ -202,10 +207,6 @@ bool llvm::formLCSSAForInstructions(SmallVectorImpl<Instruction *> &Worklist,
       // If we added a single PHI, it must dominate all uses and we can directly
       // rename it.
       if (AddedPHIs.size() == 1) {
-        // Tell the VHs that the uses changed. This updates SCEV's caches.
-        // We might call ValueIsRAUWd multiple times for the same value.
-        if (UseToRewrite->get()->hasValueHandle())
-          ValueHandleBase::ValueIsRAUWd(*UseToRewrite, AddedPHIs[0]);
         UseToRewrite->set(AddedPHIs[0]);
         continue;
       }
@@ -368,7 +369,7 @@ bool llvm::formLCSSA(Loop &L, DominatorTree &DT, LoopInfo *LI,
       Worklist.push_back(&I);
     }
   }
-  Changed = formLCSSAForInstructions(Worklist, DT, *LI);
+  Changed = formLCSSAForInstructions(Worklist, DT, *LI, SE);
 
   // If we modified the code, remove any caches about the loop from SCEV to
   // avoid dangling entries.
-- 
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