SCEVExpander fix. RAUW needs to update the InsertedExpressions cache.

Note that this bug is only exposed because LTO fails to use TTI.

Fixes self-LTO of clang. rdar://13007381.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172462 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/Analysis/ScalarEvolutionExpander.h b/include/llvm/Analysis/ScalarEvolutionExpander.h
index 1708cccf3334803046efeddf8098df66d0949305..00779fc329b115aa2132315aca11e18aee90860d 100644 (file)
--- a/include/llvm/Analysis/ScalarEvolutionExpander.h
+++ b/include/llvm/Analysis/ScalarEvolutionExpander.h
@@ -40,8 +40,10 @@ namespace llvm {
     // New instructions receive a name to identifies them with the current pass.
     const char* IVName;
 
-    std::map<std::pair<const SCEV *, Instruction *>, AssertingVH<Value> >
+    // InsertedExpressions caches Values for reuse, so must track RAUW.
+    std::map<std::pair<const SCEV *, Instruction *>, TrackingVH<Value> >
       InsertedExpressions;
+    // InsertedValues only flags inserted instructions so needs no RAUW.
     std::set<AssertingVH<Value> > InsertedValues;
     std::set<AssertingVH<Value> > InsertedPostIncValues;
 

diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp
index b87ad75389775473ef5cdd1659159eee0fc1cb06..fcd7ce272a221c9468cd199e7bb07899449ad45d 100644 (file)
--- a/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -1523,9 +1523,8 @@ Value *SCEVExpander::expand(const SCEV *S) {
     }
 
   // Check to see if we already expanded this here.
-  std::map<std::pair<const SCEV *, Instruction *>,
-           AssertingVH<Value> >::iterator I =
-    InsertedExpressions.find(std::make_pair(S, InsertPt));
+  std::map<std::pair<const SCEV *, Instruction *>, TrackingVH<Value> >::iterator
+    I = InsertedExpressions.find(std::make_pair(S, InsertPt));
   if (I != InsertedExpressions.end())
     return I->second;
 

diff --git a/test/Transforms/LoopStrengthReduce/2013-01-14-ReuseCast.ll b/test/Transforms/LoopStrengthReduce/2013-01-14-ReuseCast.ll
new file mode 100644 (file)
index 0000000..8fbddf8
--- /dev/null
+++ b/test/Transforms/LoopStrengthReduce/2013-01-14-ReuseCast.ll
@@ -0,0 +1,84 @@
+; RUN: opt -loop-reduce -S < %s | FileCheck %s
+;
+; LTO of clang, which mistakenly uses no TargetLoweringInfo, causes a
+; miscompile. ReuseOrCreateCast replace ptrtoint operand with undef.
+; Reproducing the miscompile requires no triple, hence no "TTI".
+; rdar://13007381
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+
+; Verify that nothing uses the "dead" ptrtoint from "undef".
+; CHECK: @VerifyDiagnosticConsumerTest
+; CHECK: bb:
+; CHECK: %0 = ptrtoint i8* undef to i64
+; CHECK-NOT: %0
+; CHECK: .lr.ph
+; CHECK-NOT: %0
+; CHECK: sub i64 %7, %tmp6
+; CHECK-NOT: %0
+; CHECK: ret void
+define void @VerifyDiagnosticConsumerTest() unnamed_addr nounwind uwtable align 2 {
+bb:
+  %tmp3 = call i8* @getCharData() nounwind
+  %tmp4 = call i8* @getCharData() nounwind
+  %tmp5 = ptrtoint i8* %tmp4 to i64
+  %tmp6 = ptrtoint i8* %tmp3 to i64
+  %tmp7 = sub i64 %tmp5, %tmp6
+  br i1 undef, label %bb87, label %.preheader
+
+.preheader:                                       ; preds = %bb10, %bb
+  br i1 undef, label %_ZNK4llvm9StringRef4findEcm.exit42.thread, label %bb10
+
+bb10:                                             ; preds = %.preheader
+  br i1 undef, label %_ZNK4llvm9StringRef4findEcm.exit42, label %.preheader
+
+_ZNK4llvm9StringRef4findEcm.exit42:               ; preds = %bb10
+  br i1 undef, label %_ZNK4llvm9StringRef4findEcm.exit42.thread, label %.lr.ph
+
+_ZNK4llvm9StringRef4findEcm.exit42.thread:        ; preds = %_ZNK4llvm9StringRef4findEcm.exit42, %.preheader
+  unreachable
+
+.lr.ph:                                           ; preds = %_ZNK4llvm9StringRef4findEcm.exit42
+  br label %bb36
+
+_ZNK4llvm9StringRef4findEcm.exit.loopexit:        ; preds = %bb63
+  %tmp21 = icmp eq i64 %i.0.i, -1
+  br i1 %tmp21, label %_ZNK4llvm9StringRef4findEcm.exit._crit_edge, label %bb36
+
+_ZNK4llvm9StringRef4findEcm.exit._crit_edge:      ; preds = %bb61, %_ZNK4llvm9StringRef4findEcm.exit.loopexit
+  unreachable
+
+bb36:                                             ; preds = %_ZNK4llvm9StringRef4findEcm.exit.loopexit, %.lr.ph
+  %loc.063 = phi i64 [ undef, %.lr.ph ], [ %i.0.i, %_ZNK4llvm9StringRef4findEcm.exit.loopexit ]
+  switch i8 undef, label %bb57 [
+    i8 10, label %bb48
+    i8 13, label %bb48
+  ]
+
+bb48:                                             ; preds = %bb36, %bb36
+  br label %bb58
+
+bb57:                                             ; preds = %bb36
+  br label %bb58
+
+bb58:                                             ; preds = %bb57, %bb48
+  %tmp59 = icmp ugt i64 %tmp7, undef
+  %tmp60 = select i1 %tmp59, i64 undef, i64 %tmp7
+  br label %bb61
+
+bb61:                                             ; preds = %bb63, %bb58
+  %i.0.i = phi i64 [ %tmp60, %bb58 ], [ %tmp67, %bb63 ]
+  %tmp62 = icmp eq i64 %i.0.i, %tmp7
+  br i1 %tmp62, label %_ZNK4llvm9StringRef4findEcm.exit._crit_edge, label %bb63
+
+bb63:                                             ; preds = %bb61
+  %tmp64 = getelementptr inbounds i8* %tmp3, i64 %i.0.i
+  %tmp65 = load i8* %tmp64, align 1
+  %tmp67 = add i64 %i.0.i, 1
+  br i1 undef, label %_ZNK4llvm9StringRef4findEcm.exit.loopexit, label %bb61
+
+bb87:                                             ; preds = %bb
+  ret void
+}
+
+declare i8* @getCharData()