Prevent miscompilation in trivial loop {}

Ideally, we would want to handle a broader set of cases to fully fix the
underlying bug here. That is currently relatively expensive at compile and
runtime, so we don't do that for now.
This commit is contained in:
Mark Rousskov 2020-10-15 09:28:27 -04:00
parent 7f58716810
commit e2efec8976
5 changed files with 42 additions and 9 deletions

View file

@ -334,8 +334,8 @@ impl IntrinsicCallMethods<'tcx> for Builder<'a, 'll, 'tcx> {
self.call(expect, &[cond, self.const_bool(expected)], None)
}
fn sideeffect(&mut self) {
if self.tcx.sess.opts.debugging_opts.insert_sideeffect {
fn sideeffect(&mut self, unconditional: bool) {
if unconditional || self.tcx.sess.opts.debugging_opts.insert_sideeffect {
let fnname = self.get_intrinsic(&("llvm.sideeffect"));
self.call(fnname, &[], None);
}
@ -390,7 +390,7 @@ fn codegen_msvc_try(
) {
let llfn = get_rust_try_fn(bx, &mut |mut bx| {
bx.set_personality_fn(bx.eh_personality());
bx.sideeffect();
bx.sideeffect(false);
let mut normal = bx.build_sibling_block("normal");
let mut catchswitch = bx.build_sibling_block("catchswitch");
@ -553,7 +553,7 @@ fn codegen_gnu_try(
// call %catch_func(%data, %ptr)
// ret 1
bx.sideeffect();
bx.sideeffect(false);
let mut then = bx.build_sibling_block("then");
let mut catch = bx.build_sibling_block("catch");
@ -615,7 +615,7 @@ fn codegen_emcc_try(
// call %catch_func(%data, %catch_data)
// ret 1
bx.sideeffect();
bx.sideeffect(false);
let mut then = bx.build_sibling_block("then");
let mut catch = bx.build_sibling_block("catch");