[llvm] r297839 - Refactor SimplifyCFG:canSinkInstructions [NFC]

[Aditya K via llvm-commits]

Hi Eric,
I pushed the patch because I did not see this error on x86-64. Are you seeing this on a different target.

Thanks,
-Aditya

________________________________
From: Eric Liu <ioeric at google.com>
Sent: Wednesday, March 15, 2017 9:42 AM
To: Aditya Kumar; llvm-commits at lists.llvm.org
Subject: Re: [llvm] r297839 - Refactor SimplifyCFG:canSinkInstructions [NFC]

Hi Aditya, this commit breaks Transforms/SimplifyCFG/sink-common-code.ll.

I've reverted it with r297845 :(

- Eric

On Wed, Mar 15, 2017 at 3:38 PM Aditya Kumar via llvm-commits <llvm-commits at lists.llvm.org<mailto:llvm-commits at lists.llvm.org>> wrote:
Author: hiraditya
Date: Wed Mar 15 09:26:45 2017
New Revision: 297839

URL: http://llvm.org/viewvc/llvm-project?rev=297839&view=rev
Log:
Refactor SimplifyCFG:canSinkInstructions [NFC]

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=297839&r1=297838&r2=297839&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp Wed Mar 15 09:26:45 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 (!all_of(Insts, [&PNUse,&Succ](const Instruction *I) -> bool {
+    if (!PNUse || PNUse->getParent() != Succ)
+      return false;
+    if (!all_of(Insts, [&PNUse](const Instruction *I) -> bool {
           auto *U = cast<Instruction>(*I->user_begin());
-          return (PNUse &&
-                  PNUse->getParent() == Succ &&
-                  PNUse->getIncomingValueForBlock(I->getParent()) == I) ||
-                 U->getParent() == I->getParent();
+          return (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);


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