If we have a function like this:

void bork() {
  int *address = 0;
  *address = 0;
}

It's compiled into LLVM code that looks like this:

define void @bork() noreturn nounwind  {
entry:
        unreachable
}

This is bad on some platforms (like PPC) because it will generate the label for
the function but no body. The label could end up being associated with some
non-code related stuff, like a section. This places a "trap" instruction if the
SimplifyCFG pass removed all code from the function leaving only one
"unreachable" instruction.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46387 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 0 deletions

diff --git a/test/CFrontend/2008-01-25-EmptyFunction.c b/test/CFrontend/2008-01-25-EmptyFunction.c
new file mode 100644
index 0000000..896738e
--- /dev/null
+++ b/test/CFrontend/2008-01-25-EmptyFunction.c
@@ -0,0 +1,7 @@
+// RUN: %llvmgcc -O2 -S -o - -emit-llvm %s | grep llvm.trap
+// RUN: %llvmgcc -O2 -S -o - -emit-llvm %s | grep unreachable
+
+void bork() {
+  int *address = 0;
+  *address = 0;
+}