[llvm] r297845 - Revert "Refactor SimplifyCFG:canSinkInstructions [NFC]"

[Eric Liu via llvm-commits]

Author: ioeric
Date: Wed Mar 15 10:29:42 2017
New Revision: 297845

URL: http://llvm.org/viewvc/llvm-project?rev=297845&view=rev
Log:
Revert "Refactor SimplifyCFG:canSinkInstructions [NFC]"

This reverts commit r297839, which breaks Transforms/SimplifyCFG/sink-common-code.ll

Modified:
    llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp

Modified: llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp?rev=297845&r1=297844&r2=297845&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp Wed Mar 15 10:29:42 2017
@@ -1463,39 +1463,39 @@ static bool canSinkInstructions(
   if (!isa<StoreInst>(I0)) {
     auto *PNUse = dyn_cast<PHINode>(*I0->user_begin());
     auto *Succ = I0->getParent()->getTerminator()->getSuccessor(0);
-    if (!PNUse || PNUse->getParent() != Succ)
-      return false;
-    if (!all_of(Insts, [&PNUse](const Instruction *I) -> bool {
+    if (!all_of(Insts, [&PNUse,&Succ](const Instruction *I) -> bool {
           auto *U = cast<Instruction>(*I->user_begin());
-          return (PNUse->getIncomingValueForBlock(I->getParent()) == I) ||
-                  U->getParent() == I->getParent();
+          return (PNUse &&
+                  PNUse->getParent() == Succ &&
+                  PNUse->getIncomingValueForBlock(I->getParent()) == I) ||
+                 U->getParent() == I->getParent();
         }))
       return false;
   }
 
-  // Because SROA can't handle speculating stores of selects, try not
-  // to sink loads or stores of allocas when we'd have to create a PHI for
-  // the address operand. Also, because it is likely that loads or stores
-  // of allocas will disappear when Mem2Reg/SROA is run, don't sink them.
-  // This can cause code churn which can have unintended consequences down
-  // the line - see https://llvm.org/bugs/show_bug.cgi?id=30244.
-  // FIXME: This is a workaround for a deficiency in SROA - see
-  // https://llvm.org/bugs/show_bug.cgi?id=30188
-  if (isa<StoreInst>(I0) &&
-      any_of(Insts, [](const Instruction *I) {
-        return isa<AllocaInst>(I->getOperand(1));
-      }))
-    return false;
-  if (isa<LoadInst>(I0) && any_of(Insts, [](const Instruction *I) {
-        return isa<AllocaInst>(I->getOperand(0));
-      }))
-    return false;
-
   for (unsigned OI = 0, OE = I0->getNumOperands(); OI != OE; ++OI) {
     if (I0->getOperand(OI)->getType()->isTokenTy())
       // Don't touch any operand of token type.
       return false;
 
+    // Because SROA can't handle speculating stores of selects, try not
+    // to sink loads or stores of allocas when we'd have to create a PHI for
+    // the address operand. Also, because it is likely that loads or stores
+    // of allocas will disappear when Mem2Reg/SROA is run, don't sink them.
+    // This can cause code churn which can have unintended consequences down
+    // the line - see https://llvm.org/bugs/show_bug.cgi?id=30244.
+    // FIXME: This is a workaround for a deficiency in SROA - see
+    // https://llvm.org/bugs/show_bug.cgi?id=30188
+    if (OI == 1 && isa<StoreInst>(I0) &&
+        any_of(Insts, [](const Instruction *I) {
+          return isa<AllocaInst>(I->getOperand(1));
+        }))
+      return false;
+    if (OI == 0 && isa<LoadInst>(I0) && any_of(Insts, [](const Instruction *I) {
+          return isa<AllocaInst>(I->getOperand(0));
+        }))
+      return false;
+
     auto SameAsI0 = [&I0, OI](const Instruction *I) {
       assert(I->getNumOperands() == I0->getNumOperands());
       return I->getOperand(OI) == I0->getOperand(OI);