SCEV: Use AssertingVH to catch dangling BasicBlock* when passes forget

to notify SCEV of a change. Add forgetLoop in a couple of those places.

llvm-svn: 136797

1 files changed, 88 insertions, 0 deletions

diff --git a/llvm/test/Transforms/LoopSimplify/preserve-scev.ll b/llvm/test/Transforms/LoopSimplify/preserve-scev.ll
index 017a0d21084..23ac7f257a3 100644
--- a/llvm/test/Transforms/LoopSimplify/preserve-scev.ll
+++ b/llvm/test/Transforms/LoopSimplify/preserve-scev.ll
@@ -48,3 +48,91 @@ return:                                           ; preds = %for.body18, %for.bo
 }
 
 declare void @foo() nounwind
+
+; Notify SCEV when removing an ExitingBlock.
+; CHECK: @mergeExit
+; CHECK: while.cond191:
+; CHECK: br i1 %or.cond, label %while.body197
+; CHECK-NOT: land.rhs:
+; CHECK: ret
+define void @mergeExit(i32 %MapAttrCount) nounwind uwtable ssp {
+entry:
+  br i1 undef, label %if.then124, label %if.end126
+
+if.then124:                                       ; preds = %entry
+  unreachable
+
+if.end126:                                        ; preds = %entry
+  br i1 undef, label %while.body.lr.ph, label %if.end591
+
+while.body.lr.ph:                                 ; preds = %if.end126
+  br i1 undef, label %if.end140, label %if.then137
+
+if.then137:                                       ; preds = %while.body.lr.ph
+  unreachable
+
+if.end140:                                        ; preds = %while.body.lr.ph
+  br i1 undef, label %while.cond191.outer, label %if.then148
+
+if.then148:                                       ; preds = %if.end140
+  unreachable
+
+while.cond191.outer:                              ; preds = %if.then205, %if.end140
+  br label %while.cond191
+
+while.cond191:                                    ; preds = %while.body197, %while.cond191.outer
+  %CppIndex.0 = phi i32 [ %inc, %while.body197 ], [ undef, %while.cond191.outer ]
+  br i1 undef, label %land.rhs, label %if.then216
+
+land.rhs:                                         ; preds = %while.cond191
+  %inc = add i32 %CppIndex.0, 1
+  %cmp196 = icmp ult i32 %inc, %MapAttrCount
+  br i1 %cmp196, label %while.body197, label %if.then216
+
+while.body197:                                    ; preds = %land.rhs
+  br i1 undef, label %if.then205, label %while.cond191
+
+if.then205:                                       ; preds = %while.body197
+  br label %while.cond191.outer
+
+if.then216:                                       ; preds = %land.rhs, %while.cond191
+  br i1 undef, label %if.else, label %if.then221
+
+if.then221:                                       ; preds = %if.then216
+  unreachable
+
+if.else:                                          ; preds = %if.then216
+  br i1 undef, label %if.then266, label %if.end340
+
+if.then266:                                       ; preds = %if.else
+  switch i32 undef, label %if.else329 [
+    i32 17, label %if.then285
+    i32 19, label %if.then285
+    i32 18, label %if.then285
+    i32 15, label %if.then285
+  ]
+
+if.then285:                                       ; preds = %if.then266, %if.then266, %if.then266, %if.then266
+  br i1 undef, label %if.then317, label %if.else324
+
+if.then317:                                       ; preds = %if.then285
+  br label %if.end340
+
+if.else324:                                       ; preds = %if.then285
+  unreachable
+
+if.else329:                                       ; preds = %if.then266
+  unreachable
+
+if.end340:                                        ; preds = %if.then317, %if.else
+  unreachable
+
+if.end591:                                        ; preds = %if.end126
+  br i1 undef, label %cond.end, label %cond.false
+
+cond.false:                                       ; preds = %if.end591
+  unreachable
+
+cond.end:                                         ; preds = %if.end591
+  ret void
+}