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.
llvm-svn: 46387
diff --git a/llvm/test/CFrontend/2008-01-25-EmptyFunction.c b/llvm/test/CFrontend/2008-01-25-EmptyFunction.c
new file mode 100644
index 0000000..896738e
--- /dev/null
+++ b/llvm/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;
+}