[llvm] r301599 - [SROA] Fix nondeterminism exposed by Simon's r299221.

[Davide Italiano via llvm-commits]

Author: davide
Date: Thu Apr 27 18:09:01 2017
New Revision: 301599

URL: http://llvm.org/viewvc/llvm-project?rev=301599&view=rev
Log:
[SROA] Fix nondeterminism exposed by Simon's r299221.

Use a SmallSetSetVector instead of a SmallPtrSet as iterating
over the latter is not stable ('<' relies on addresses).

Modified:
    llvm/trunk/lib/Transforms/Scalar/SROA.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/SROA.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/SROA.cpp?rev=301599&r1=301598&r2=301599&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/SROA.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/SROA.cpp Thu Apr 27 18:09:01 2017
@@ -25,6 +25,7 @@
 
 #include "llvm/Transforms/Scalar/SROA.h"
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/AssumptionCache.h"
@@ -2186,8 +2187,8 @@ class llvm::sroa::AllocaSliceRewriter
   Instruction *OldPtr;
 
   // Track post-rewrite users which are PHI nodes and Selects.
-  SmallPtrSetImpl<PHINode *> &PHIUsers;
-  SmallPtrSetImpl<SelectInst *> &SelectUsers;
+  SmallSetVector<PHINode *, 8> &PHIUsers;
+  SmallSetVector<SelectInst *, 8> &SelectUsers;
 
   // Utility IR builder, whose name prefix is setup for each visited use, and
   // the insertion point is set to point to the user.
@@ -2199,8 +2200,8 @@ public:
                       uint64_t NewAllocaBeginOffset,
                       uint64_t NewAllocaEndOffset, bool IsIntegerPromotable,
                       VectorType *PromotableVecTy,
-                      SmallPtrSetImpl<PHINode *> &PHIUsers,
-                      SmallPtrSetImpl<SelectInst *> &SelectUsers)
+                      SmallSetVector<PHINode *, 8> &PHIUsers,
+                      SmallSetVector<SelectInst *, 8> &SelectUsers)
       : DL(DL), AS(AS), Pass(Pass), OldAI(OldAI), NewAI(NewAI),
         NewAllocaBeginOffset(NewAllocaBeginOffset),
         NewAllocaEndOffset(NewAllocaEndOffset),
@@ -3880,8 +3881,8 @@ AllocaInst *SROA::rewritePartition(Alloc
   // fact scheduled for promotion.
   unsigned PPWOldSize = PostPromotionWorklist.size();
   unsigned NumUses = 0;
-  SmallPtrSet<PHINode *, 8> PHIUsers;
-  SmallPtrSet<SelectInst *, 8> SelectUsers;
+  SmallSetVector<PHINode *, 8> PHIUsers;
+  SmallSetVector<SelectInst *, 8> SelectUsers;
 
   AllocaSliceRewriter Rewriter(DL, AS, *this, AI, *NewAI, P.beginOffset(),
                                P.endOffset(), IsIntegerPromotable, VecTy,
@@ -3902,19 +3903,16 @@ AllocaInst *SROA::rewritePartition(Alloc
 
   // Now that we've processed all the slices in the new partition, check if any
   // PHIs or Selects would block promotion.
-  for (SmallPtrSetImpl<PHINode *>::iterator I = PHIUsers.begin(),
-                                            E = PHIUsers.end();
-       I != E; ++I)
-    if (!isSafePHIToSpeculate(**I)) {
+  for (PHINode *PHI : PHIUsers)
+    if (!isSafePHIToSpeculate(*PHI)) {
       Promotable = false;
       PHIUsers.clear();
       SelectUsers.clear();
       break;
     }
-  for (SmallPtrSetImpl<SelectInst *>::iterator I = SelectUsers.begin(),
-                                               E = SelectUsers.end();
-       I != E; ++I)
-    if (!isSafeSelectToSpeculate(**I)) {
+
+  for (SelectInst *Sel : SelectUsers)
+    if (!isSafeSelectToSpeculate(*Sel)) {
       Promotable = false;
       PHIUsers.clear();
       SelectUsers.clear();