From d0986f45e094b011d132238563b05c09e4f1e20e Mon Sep 17 00:00:00 2001
From: DianQK <dianqk@dianqk.net>
Date: Mon, 9 Dec 2024 20:25:41 +0800
Subject: [PATCH] dataflow_const_prop: do not eval a ptr address in SwitchInt
---
.../src/dataflow_const_prop.rs | 9 +++++++--
tests/crashes/131227.rs | 16 ----------------
.../ptr-in-switch-int-issue-131227.rs | 19 +++++++++++++++++++
3 files changed, 26 insertions(+), 18 deletions(-)
delete mode 100644 tests/crashes/131227.rs
create mode 100644 tests/ui/dataflow_const_prop/ptr-in-switch-int-issue-131227.rs
diff --git a/compiler/rustc_mir_transform/src/dataflow_const_prop.rs b/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
index d017202f48bb9..b94c925b1dbd7 100644
--- a/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
+++ b/compiler/rustc_mir_transform/src/dataflow_const_prop.rs
@@ -534,8 +534,13 @@ impl<'a, 'tcx> ConstAnalysis<'a, 'tcx> {
// This allows the set of visited edges to grow monotonically with the lattice.
FlatSet::Bottom => TerminatorEdges::None,
FlatSet::Elem(scalar) => {
- let choice = scalar.assert_scalar_int().to_bits_unchecked();
- TerminatorEdges::Single(targets.target_for_value(choice))
+ if let Ok(scalar_int) = scalar.try_to_scalar_int() {
+ TerminatorEdges::Single(
+ targets.target_for_value(scalar_int.to_bits_unchecked()),
+ )
+ } else {
+ TerminatorEdges::SwitchInt { discr, targets }
+ }
}
FlatSet::Top => TerminatorEdges::SwitchInt { discr, targets },
}
diff --git a/tests/crashes/131227.rs b/tests/crashes/131227.rs
deleted file mode 100644
index f46185b5b4a66..0000000000000
--- a/tests/crashes/131227.rs
+++ /dev/null
@@ -1,16 +0,0 @@
-//@ known-bug: #131227
-//@ compile-flags: -Zmir-opt-level=3
-
-static mut G: () = ();
-
-fn myfunc() -> i32 {
- let var = &raw mut G;
- if var.is_null() {
- return 0;
- }
- 0
-}
-
-fn main() {
- myfunc();
-}
diff --git a/tests/ui/dataflow_const_prop/ptr-in-switch-int-issue-131227.rs b/tests/ui/dataflow_const_prop/ptr-in-switch-int-issue-131227.rs
new file mode 100644
index 0000000000000..7a55e13d0eed0
--- /dev/null
+++ b/tests/ui/dataflow_const_prop/ptr-in-switch-int-issue-131227.rs
@@ -0,0 +1,19 @@
+//! Issue: <https://github.com/rust-lang/rust/issues/131227>
+//! Test that constant propagation in SwitchInt does not crash
+//! when encountering a ptr-to-int transmute.
+
+//@ check-pass
+//@ compile-flags: -Zmir-enable-passes=+InstSimplify-before-inline,+DataflowConstProp
+
+#![crate_type = "lib"]
+
+static mut G: i32 = 0;
+
+pub fn myfunc() -> i32 {
+ let var = &raw mut G;
+ let u: usize = unsafe { std::mem::transmute(var) };
+ match u {
+ 0 => 0,
+ _ => 1,
+ }
+}