fix ShrinkDemandedOps to not leave dead nodes around,

fixing PR6607


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98512 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 25 insertions, 0 deletions

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index f6828ae..72e61d3 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -509,6 +509,12 @@ void SelectionDAGISel::ShrinkDemandedOps() {
     InWorklist.erase(N);
 
     if (N->use_empty() && N != CurDAG->getRoot().getNode()) {
+      // Deleting this node may make its operands dead, add them to the worklist
+      // if they aren't already there.
+      for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
+        if (InWorklist.insert(N->getOperand(i).getNode()))
+          Worklist.push_back(N->getOperand(i).getNode());
+      
       CurDAG->DeleteNode(N);
       continue;
     }
diff --git a/test/CodeGen/X86/crash.ll b/test/CodeGen/X86/crash.ll
index b75d265..cfa1270 100644
--- a/test/CodeGen/X86/crash.ll
+++ b/test/CodeGen/X86/crash.ll
@@ -71,3 +71,22 @@ return:                                           ; preds = %if.else, %entry
 }
 
 declare i32 @safe(i32)
+
+; PR6607
+define fastcc void @test5(i32 %FUNC) nounwind {
+foo:
+  %0 = load i8* undef, align 1                    ; <i8> [#uses=3]
+  %1 = sext i8 %0 to i32                          ; <i32> [#uses=2]
+  %2 = zext i8 %0 to i32                          ; <i32> [#uses=1]
+  %tmp1.i5037 = urem i32 %2, 10                   ; <i32> [#uses=1]
+  %tmp.i5038 = icmp ugt i32 %tmp1.i5037, 15       ; <i1> [#uses=1]
+  %3 = zext i1 %tmp.i5038 to i8                   ; <i8> [#uses=1]
+  %4 = icmp slt i8 %0, %3                         ; <i1> [#uses=1]
+  %5 = add nsw i32 %1, 256                        ; <i32> [#uses=1]
+  %storemerge.i.i57 = select i1 %4, i32 %5, i32 %1 ; <i32> [#uses=1]
+  %6 = shl i32 %storemerge.i.i57, 16              ; <i32> [#uses=1]
+  %7 = sdiv i32 %6, -256                          ; <i32> [#uses=1]
+  %8 = trunc i32 %7 to i8                         ; <i8> [#uses=1]
+  store i8 %8, i8* undef, align 1
+  ret void
+}