Change enum->int casts to not go through MIR casts.

Instead we generate a discriminant rvalue and cast the result of that.

4 files changed, 14 insertions, 7 deletions

diff --git a/src/test/codegen/enum-bounds-check-derived-idx.rs b/src/test/codegen/enum-bounds-check-derived-idx.rs
index aa66c2ed08e..fe02aeb5f62 100644
--- a/src/test/codegen/enum-bounds-check-derived-idx.rs
+++ b/src/test/codegen/enum-bounds-check-derived-idx.rs
@@ -12,13 +12,15 @@ pub enum Bar {
 // CHECK-LABEL: @lookup_inc
 #[no_mangle]
 pub fn lookup_inc(buf: &[u8; 5], f: Bar) -> u8 {
-    // CHECK-NOT: panic_bounds_check
+    // FIXME: panic check can be removed by adding the assumes back after https://github.com/rust-lang/rust/pull/98332
+    // CHECK: panic_bounds_check
     buf[f as usize + 1]
 }
 
 // CHECK-LABEL: @lookup_dec
 #[no_mangle]
 pub fn lookup_dec(buf: &[u8; 5], f: Bar) -> u8 {
-    // CHECK-NOT: panic_bounds_check
+    // FIXME: panic check can be removed by adding the assumes back after https://github.com/rust-lang/rust/pull/98332
+    // CHECK: panic_bounds_check
     buf[f as usize - 1]
 }
diff --git a/src/test/codegen/enum-bounds-check-issue-13926.rs b/src/test/codegen/enum-bounds-check-issue-13926.rs
index b26945bc549..1aec41d5441 100644
--- a/src/test/codegen/enum-bounds-check-issue-13926.rs
+++ b/src/test/codegen/enum-bounds-check-issue-13926.rs
@@ -13,6 +13,7 @@ pub enum Exception {
 // CHECK-LABEL: @access
 #[no_mangle]
 pub fn access(array: &[usize; 12], exc: Exception) -> usize {
-    // CHECK-NOT: panic_bounds_check
+    // FIXME: panic check can be removed by adding the assumes back after https://github.com/rust-lang/rust/pull/98332
+    // CHECK: panic_bounds_check
     array[(exc as u8 - 4) as usize]
 }
diff --git a/src/test/codegen/enum-bounds-check-issue-82871.rs b/src/test/codegen/enum-bounds-check-issue-82871.rs
index a1fa1387d94..32fdc4a5f4f 100644
--- a/src/test/codegen/enum-bounds-check-issue-82871.rs
+++ b/src/test/codegen/enum-bounds-check-issue-82871.rs
@@ -1,4 +1,4 @@
-// compile-flags: -O
+// compile-flags: -C opt-level=0
 
 #![crate_type = "lib"]
 
@@ -9,7 +9,10 @@ pub enum E {
 
 // CHECK-LABEL: @index
 #[no_mangle]
-pub fn index(x: &[u32; 3], ind: E) -> u32{
-    // CHECK-NOT: panic_bounds_check
+pub fn index(x: &[u32; 3], ind: E) -> u32 {
+    // Canary: we should be able to optimize out the bounds check, but we need
+    // to track the range of the discriminant result in order to be able to do that.
+    // oli-obk tried to add that, but that caused miscompilations all over the place.
+    // CHECK: panic_bounds_check
     x[ind as usize]
 }
diff --git a/src/test/codegen/enum-bounds-check.rs b/src/test/codegen/enum-bounds-check.rs
index 17322d5911b..f85c6817ded 100644
--- a/src/test/codegen/enum-bounds-check.rs
+++ b/src/test/codegen/enum-bounds-check.rs
@@ -21,6 +21,7 @@ pub enum Bar {
 // CHECK-LABEL: @lookup_unmodified
 #[no_mangle]
 pub fn lookup_unmodified(buf: &[u8; 5], f: Bar) -> u8 {
-    // CHECK-NOT: panic_bounds_check
+    // FIXME: panic check can be removed by adding the assumes back after https://github.com/rust-lang/rust/pull/98332
+    // CHECK: panic_bounds_check
     buf[f as usize]
 }