Fix what is _hopefully_ the last corner case for loops.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40503 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp
index f3aa7960f66a3b87c0c51347ee72bac24ed099da..d7e622857aeb736fd75e5bca2f99d878dbaf0422 100644 (file)
--- a/lib/Transforms/Scalar/GVN.cpp
+++ b/lib/Transforms/Scalar/GVN.cpp
@@ -738,8 +738,12 @@ Value *GVN::performPHIConstruction(BasicBlock *BB, LoadInst* orig,
     for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
       if (!visited.count(*PI))
         PN->addIncoming(performPHIConstruction(*PI, orig, Phis, visited), *PI);
-      else
-        PN->addIncoming(Phis[*PI], *PI);
+      else {
+        if (Phis[*PI])
+          PN->addIncoming(Phis[*PI], *PI);
+        else
+          PN->addIncoming(PN, *PI);
+      }
     visited.erase(BB);
     
     bool all_same = PN->getNumIncomingValues() != 1;

diff --git a/test/Transforms/GVN/2007-07-25-DominatedLoop.ll b/test/Transforms/GVN/2007-07-25-DominatedLoop.ll
new file mode 100644 (file)
index 0000000..7c10f97
--- /dev/null
+++ b/test/Transforms/GVN/2007-07-25-DominatedLoop.ll
@@ -0,0 +1,86 @@
+; RUN: llvm-as < %s | opt -gvn | llvm-dis
+
+       %struct.PerlInterpreter = type { i8 }
+@PL_sv_count = external global i32             ; <i32*> [#uses=2]
+
+define void @perl_destruct(%struct.PerlInterpreter* %sv_interp) {
+entry:
+       br i1 false, label %cond_next25, label %cond_true16
+
+cond_true16:           ; preds = %entry
+       ret void
+
+cond_next25:           ; preds = %entry
+       br i1 false, label %cond_next33, label %cond_true32
+
+cond_true32:           ; preds = %cond_next25
+       ret void
+
+cond_next33:           ; preds = %cond_next25
+       br i1 false, label %cond_next61, label %cond_true.i46
+
+cond_true.i46:         ; preds = %cond_next33
+       ret void
+
+cond_next61:           ; preds = %cond_next33
+       br i1 false, label %cond_next69, label %cond_true66
+
+cond_true66:           ; preds = %cond_next61
+       ret void
+
+cond_next69:           ; preds = %cond_next61
+       br i1 false, label %Perl_safefree.exit52, label %cond_true.i50
+
+cond_true.i50:         ; preds = %cond_next69
+       ret void
+
+Perl_safefree.exit52:          ; preds = %cond_next69
+       br i1 false, label %cond_next80, label %cond_true77
+
+cond_true77:           ; preds = %Perl_safefree.exit52
+       ret void
+
+cond_next80:           ; preds = %Perl_safefree.exit52
+       br i1 false, label %Perl_safefree.exit56, label %cond_true.i54
+
+cond_true.i54:         ; preds = %cond_next80
+       ret void
+
+Perl_safefree.exit56:          ; preds = %cond_next80
+       br i1 false, label %Perl_safefree.exit60, label %cond_true.i58
+
+cond_true.i58:         ; preds = %Perl_safefree.exit56
+       ret void
+
+Perl_safefree.exit60:          ; preds = %Perl_safefree.exit56
+       br i1 false, label %Perl_safefree.exit64, label %cond_true.i62
+
+cond_true.i62:         ; preds = %Perl_safefree.exit60
+       ret void
+
+Perl_safefree.exit64:          ; preds = %Perl_safefree.exit60
+       br i1 false, label %Perl_safefree.exit68, label %cond_true.i66
+
+cond_true.i66:         ; preds = %Perl_safefree.exit64
+       ret void
+
+Perl_safefree.exit68:          ; preds = %Perl_safefree.exit64
+       br i1 false, label %cond_next150, label %cond_true23.i
+
+cond_true23.i:         ; preds = %Perl_safefree.exit68
+       ret void
+
+cond_next150:          ; preds = %Perl_safefree.exit68
+       %tmp16092 = load i32* @PL_sv_count, align 4             ; <i32> [#uses=0]
+       br label %cond_next165
+
+bb157:         ; preds = %cond_next165
+       %tmp158 = load i32* @PL_sv_count, align 4               ; <i32> [#uses=0]
+       br label %cond_next165
+
+cond_next165:          ; preds = %bb157, %cond_next150
+       br i1 false, label %bb171, label %bb157
+
+bb171:         ; preds = %cond_next165
+       ret void
+}