llvm-reduce: Add pass to reduce basic blocks

Patch by Diego Treviño!

Differential Revision: https://reviews.llvm.org/D66320

llvm-svn: 372264

1 files changed, 29 insertions, 0 deletions

diff --git a/llvm/test/Reduce/remove-bbs.ll b/llvm/test/Reduce/remove-bbs.ll
new file mode 100644
index 00000000000..9e49bc53168
--- /dev/null
+++ b/llvm/test/Reduce/remove-bbs.ll
@@ -0,0 +1,29 @@
+; Test that llvm-reduce can remove uninteresting Basic Blocks, and remove them from instructions (i.e. SwitchInst, BranchInst and IndirectBrInst)
+; Note: if an uninteresting BB is the default case for a switch, the instruction is removed altogether (since the default case cannot be replaced)
+;
+; RUN: llvm-reduce --test %python --test-arg %p/Inputs/remove-bbs.py %s -o %t
+; RUN: cat %t | FileCheck -implicit-check-not=uninteresting %s
+
+define void @main() {
+interesting:
+  ; CHECK-NOT: switch i32 0, label %uninteresting
+  switch i32 0, label %uninteresting [
+    i32 0, label %uninteresting
+  ]
+
+uninteresting:
+  ret void
+
+interesting2:
+  ; CHECK: switch i32 1, label %interesting3
+  switch i32 1, label %interesting3 [
+    ; CHECK-NOT: i32 0, label %uninteresting
+    i32 0, label %uninteresting
+    ; CHECK: i32 1, label %interesting3
+    i32 1, label %interesting3
+  ]
+
+interesting3:
+  ; CHECK: br label %interesting2
+  br i1 true, label %interesting2, label %uninteresting
+}