Use WeakVH instead of WeakTrackingVH in AliasSetTracker's UnkownInsts

In cases where an instruction (a call site, say) is RAUW'ed with some
other value (this is possible via the `returned` attribute, for
instance), we want the slot in UnknownInsts to point to the original
Instruction we wanted to track, not the value it got replaced by.

Fixes PR32587.

This relands r301426.

llvm-svn: 301814

diff --git a/llvm/include/llvm/Analysis/AliasSetTracker.h b/llvm/include/llvm/Analysis/AliasSetTracker.h
index d150f89..eac9750 100644 (file)
--- a/llvm/include/llvm/Analysis/AliasSetTracker.h
+++ b/llvm/include/llvm/Analysis/AliasSetTracker.h
@@ -121,10 +121,10 @@ class AliasSet : public ilist_node<AliasSet> {
   AliasSet *Forward;
 
   /// All instructions without a specific address in this alias set.
-  /// In rare cases this vector can have a null'ed out WeakTrackingVH
+  /// In rare cases this vector can have a null'ed out WeakVH
   /// instances (can happen if some other loop pass deletes an
   /// instruction in this list).
-  std::vector<WeakTrackingVH> UnknownInsts;
+  std::vector<WeakVH> UnknownInsts;
 
   /// Number of nodes pointing to this AliasSet plus the number of AliasSets
   /// forwarding to it.

diff --git a/llvm/test/Analysis/AliasSet/unknown-inst-tracking.ll b/llvm/test/Analysis/AliasSet/unknown-inst-tracking.ll
new file mode 100644 (file)
index 0000000..da528fb
--- /dev/null
+++ b/llvm/test/Analysis/AliasSet/unknown-inst-tracking.ll
@@ -0,0 +1,25 @@
+; RUN: opt -S -licm -loop-unswitch < %s | FileCheck %s
+
+; This test checks for a crash.  See PR32587.
+
+@global = external global i32
+
+declare i32 @f_1(i8, i32 returned)
+
+define i32 @f_0() {
+; CHECK-LABEL: @f_0(
+bb:
+  br label %bb1
+
+bb1:                                              ; preds = %bb3, %bb
+  %tmp = load i32, i32* @global
+  %tmp2 = select i1 false, i16 1, i16 0
+  br label %bb3
+
+bb3:                                              ; preds = %bb3, %bb1
+  %tmp4 = phi i8 [ 0, %bb1 ], [ %tmp6, %bb3 ]
+  %tmp5 = icmp eq i16 %tmp2, 0
+  %tmp6 = select i1 %tmp5, i8 %tmp4, i8 1
+  %tmp7 = tail call i32 @f_1(i8 %tmp6, i32 1)
+  br i1 false, label %bb1, label %bb3
+}