New testcase, details in the comments

llvm-svn: 11495

1 files changed, 32 insertions, 0 deletions

diff --git a/llvm/test/Regression/Transforms/SimplifyCFG/UncondBranchToReturn.ll b/llvm/test/Regression/Transforms/SimplifyCFG/UncondBranchToReturn.ll
new file mode 100644
index 00000000000..6e943f35fb1
--- /dev/null
+++ b/llvm/test/Regression/Transforms/SimplifyCFG/UncondBranchToReturn.ll
@@ -0,0 +1,32 @@
+; The unify-function-exit-nodes pass often makes basic blocks that just contain
+; a PHI node and a return.  Make sure the simplify cfg can straighten out this
+; important case.  This is basically the most trivial form of tail-duplication.
+
+; RUN: llvm-as < %s | opt -simplifycfg | llvm-dis | not grep 'br label'
+
+int %test(bool %B, int %A, int %B) {
+	br bool %B, label %T, label %F
+T:
+	br label %ret
+F:
+	br label %ret
+ret:
+	%X = phi int [%A, %F], [%B, %T]
+	ret int %X
+}
+
+; Make sure it's willing to move unconditional branches to return instructions
+; as well, even if the return block is shared and the source blocks are
+; non-empty.
+int %test2(bool %B, int %A, int %B) {
+	br bool %B, label %T, label %F
+T:
+	call int %test(bool true, int 5, int 8)
+	br label %ret
+F:
+	call int %test(bool true, int 5, int 8)
+	br label %ret
+ret:
+	ret int %A
+}
+