[LoopDeletion] Add test for PR49967 (NFC)

Test case for a SCEV invalidation bug caused by D100264, which
has since been reverted.

diff --git a/llvm/test/Transforms/LoopDeletion/pr49967.ll b/llvm/test/Transforms/LoopDeletion/pr49967.ll
new file mode 100644 (file)
index 0000000..754ac31
--- /dev/null
+++ b/llvm/test/Transforms/LoopDeletion/pr49967.ll
@@ -0,0 +1,54 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -loop-deletion -enable-new-pm=0 < %s | FileCheck %s
+
+; Make sure this does not crash due to incorrect SCEV invalidation (PR49967).
+
+define void @test() {
+; CHECK-LABEL: @test(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[VECTOR_PH:%.*]]
+; CHECK:       vector.ph:
+; CHECK-NEXT:    br label [[FOR_BODY63:%.*]]
+; CHECK:       for.cond.cleanup62:
+; CHECK-NEXT:    br i1 true, label [[FOR_BODY151_PREHEADER:%.*]], label [[VECTOR_PH]]
+; CHECK:       for.body151.preheader:
+; CHECK-NEXT:    br label [[FOR_COND_CLEANUP150_LOOPEXIT:%.*]]
+; CHECK:       for.body63:
+; CHECK-NEXT:    [[I58_010:%.*]] = phi i16 [ 32, [[VECTOR_PH]] ]
+; CHECK-NEXT:    store i16 undef, i16* undef, align 1
+; CHECK-NEXT:    [[INC89:%.*]] = add nuw nsw i16 [[I58_010]], 1
+; CHECK-NEXT:    [[EXITCOND12_NOT:%.*]] = icmp eq i16 [[INC89]], 33
+; CHECK-NEXT:    br i1 [[EXITCOND12_NOT]], label [[FOR_COND_CLEANUP62:%.*]], label [[FOR_BODY63_FOR_BODY63_CRIT_EDGE:%.*]]
+; CHECK:       for.body63.for.body63_crit_edge:
+; CHECK-NEXT:    unreachable
+; CHECK:       for.cond.cleanup150.loopexit:
+; CHECK-NEXT:    unreachable
+;
+entry:
+  br label %vector.ph
+
+vector.ph:                                        ; preds = %for.cond.cleanup62, %entry
+  br label %for.body63
+
+for.cond.cleanup62:                               ; preds = %for.body63
+  br i1 true, label %for.body151.preheader, label %vector.ph
+
+for.body151.preheader:                            ; preds = %for.cond.cleanup62
+  br label %for.body151
+
+for.body63:                                       ; preds = %for.body63, %vector.ph
+  %i58.010 = phi i16 [ 32, %vector.ph ], [ %inc89, %for.body63 ]
+  store i16 undef, i16* undef, align 1
+  %inc89 = add nuw nsw i16 %i58.010, 1
+  %exitcond12.not = icmp eq i16 %inc89, 33
+  br i1 %exitcond12.not, label %for.cond.cleanup62, label %for.body63
+
+for.cond.cleanup150.loopexit:                     ; preds = %for.body151
+  unreachable
+
+for.body151:                                      ; preds = %for.body151.preheader, %for.body151
+  %i146.29 = phi i16 [ %inc177, %for.body151 ], [ undef, %for.body151.preheader ]
+  %inc177 = add nuw nsw i16 %i146.29, 1
+  %exitcond.not = icmp eq i16 %inc177, 32
+  br i1 %exitcond.not, label %for.cond.cleanup150.loopexit, label %for.body151
+}