Fix PR3411. When replacing values, nodes are analyzed

in any old order.  Since analyzing a node analyzes its
operands also, this can mean that when we pop a node
off the list of nodes to be analyzed, it may already
have been analyzed.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63632 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 37 insertions, 5 deletions

diff --git a/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp b/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
index 83712ee..7117604 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
@@ -651,7 +651,7 @@ namespace {
       DTL.NoteDeletion(N, E);
 
       // In theory the deleted node could also have been scheduled for analysis.
-      // So add it to the set of nodes which will not be analyzed.
+      // So remove it from the set of nodes which will be analyzed.
       NodesToAnalyze.remove(N);
 
       // In general nothing needs to be done for E, since it didn't change but
@@ -669,6 +669,7 @@ namespace {
       assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess &&
              N->getNodeId() != DAGTypeLegalizer::Processed &&
              "Invalid node ID for RAUW deletion!");
+      N->setNodeId(DAGTypeLegalizer::NewNode);
       NodesToAnalyze.insert(N);
     }
   };
@@ -695,12 +696,13 @@ void DAGTypeLegalizer::ReplaceValueWithHelper(SDValue From, SDValue To) {
   while (!NodesToAnalyze.empty()) {
     SDNode *N = NodesToAnalyze.back();
     NodesToAnalyze.pop_back();
+    if (N->getNodeId() != DAGTypeLegalizer::NewNode)
+      // The node was analyzed while reanalyzing an earlier node - it is safe to
+      // skip.  Note that this is not a morphing node - otherwise it would still
+      // be marked NewNode.
+      continue;
 
     // Analyze the node's operands and recalculate the node ID.
-    assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess &&
-           N->getNodeId() != DAGTypeLegalizer::Processed &&
-           "Invalid node ID for RAUW analysis!");
-    N->setNodeId(NewNode);
     SDNode *M = AnalyzeNewNode(N);
     if (M != N) {
       // The node morphed into a different node.  Make everyone use the new node
diff --git a/test/CodeGen/X86/2009-02-03-AnalyzedTwice.ll b/test/CodeGen/X86/2009-02-03-AnalyzedTwice.ll
new file mode 100644
index 0000000..5f97ee7
--- /dev/null
+++ b/test/CodeGen/X86/2009-02-03-AnalyzedTwice.ll
@@ -0,0 +1,30 @@
+; RUN: llvm-as < %s | llc -march=x86
+; PR3411
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32"
+target triple = "i386-pc-linux-gnu"
+@g_3 = external global i32		; <i32*> [#uses=1]
+
+define void @bar(i64 %p_66) nounwind {
+entry:
+	br i1 false, label %bb, label %bb1
+
+bb:		; preds = %entry
+	unreachable
+
+bb1:		; preds = %entry
+	%0 = load i32* @g_3, align 4		; <i32> [#uses=2]
+	%1 = sext i32 %0 to i64		; <i64> [#uses=1]
+	%2 = or i64 %1, %p_66		; <i64> [#uses=1]
+	%3 = shl i64 %2, 0		; <i64> [#uses=1]
+	%4 = and i64 %3, %p_66		; <i64> [#uses=1]
+	%5 = icmp eq i64 %4, 1		; <i1> [#uses=1]
+	%6 = trunc i64 %p_66 to i32		; <i32> [#uses=2]
+	%7 = or i32 %0, %6		; <i32> [#uses=2]
+	%8 = sub i32 %7, %6		; <i32> [#uses=1]
+	%iftmp.0.0 = select i1 %5, i32 %8, i32 %7		; <i32> [#uses=1]
+	%9 = tail call i32 @foo(i32 %iftmp.0.0) nounwind		; <i32> [#uses=0]
+	ret void
+}
+
+declare i32 @foo(i32)