1 files changed, 101 insertions, 0 deletions
diff --git a/llvm/test/Transforms/SimpleLoopUnswitch/delete-dead-blocks.ll b/llvm/test/Transforms/SimpleLoopUnswitch/delete-dead-blocks.ll
new file mode 100644
index 00000000000..aa10670cb4e
--- /dev/null
+++ b/llvm/test/Transforms/SimpleLoopUnswitch/delete-dead-blocks.ll
@@ -0,0 +1,101 @@
+; RUN: opt < %s -simple-loop-unswitch -enable-nontrivial-unswitch -S 2>&1 | FileCheck %s
+; RUN: opt < %s -passes=unswitch -enable-nontrivial-unswitch -S 2>&1 | FileCheck %s
+;
+; Checking that (dead) blocks from inner loop are deleted after unswitch.
+;
+declare void @foo()
+
+; CHECK-LABEL: @Test
+define void @Test(i32) {
+entry:
+  br label %outer
+outer:
+  %oi = phi i32 [ 0, %entry ], [ %oinc, %outer_continue]
+  br label %inner
+inner:
+  %ii = phi i32 [ 0, %outer ], [ %iinc, %continue]
+  call void @foo() 
+  switch i32 %0, label %get_out2 [
+    i32 0, label %continue
+    i32 1, label %case1
+    i32 2, label %get_out
+  ]
+;
+; since we unswitch on the above switch, %case1 and %continue blocks
+; become dead in the original loop
+;
+; CHECK-NOT: case1:
+case1:
+  br label %continue
+; CHECK-NOT: {{^}}continue:
+continue:
+  %iinc = add i32 %ii, 1
+  %icmp = icmp eq i32 %ii, 100
+  br i1 %icmp, label %inner, label %outer_continue
+
+outer_continue:
+  %oinc = add i32 %oi, 1
+  %ocmp = icmp eq i32 %oi, 100
+  br i1 %ocmp, label %outer, label %get_out
+
+get_out:
+  ret void
+get_out2:
+  unreachable
+}
+
+;
+; This comes from PR38778
+; CHECK-LABEL: @Test2
+define void @Test2(i32) {
+header:
+  br label %loop
+loop:
+  switch i32 %0, label %continue [
+    i32 -2147483648, label %check
+    i32 98, label %guarded1
+    i32 99, label %guarded2
+  ]
+; CHECK-NOT: {{^}}guarded1:
+guarded1:
+  br i1 undef, label %continue, label %leave
+guarded2:
+  br label %continue
+check:
+  %val = add i32 0, 1
+  br i1 undef, label %continue, label %leave
+continue:
+  br label %loop
+leave:
+  %local = phi i32 [ 0, %guarded1 ], [ %val, %check ]
+  ret void
+}
+
+;
+; Yet another test from PR38778
+;
+; CHECK-LABEL: @Test3
+define void @Test3(i32) {
+header:
+  br label %outer
+outer:
+  %bad_input.i = icmp eq i32 %0, -2147483648
+  br label %inner
+inner:
+  br i1 %bad_input.i, label %overflow, label %switchme
+overflow:
+  br label %continue
+switchme:
+  switch i32 %0, label %continue [
+    i32 88, label %go_out
+    i32 99, label %case2
+  ]
+; CHECK-NOT: {{^}}case2:
+case2:
+  br label %continue
+continue:
+  %local_11_92 = phi i32 [ 0, %switchme ], [ 18, %case2 ], [ 0, %overflow ]
+  br i1 undef, label %outer, label %inner
+go_out:
+  unreachable
+}