Auto merge of #127234 - ZhuUx:inlined-expr, r=davidtwco,Zalathar

[Coverage][MCDC] Group mcdc tests and fix panic when generating mcdc code for inlined expressions.

### Changes

1. Group all mcdc tests to one directory.
2. Since mcdc instruments different mappings for boolean expressions with normal branch coverage as #125766 introduces, it would be better also trace branch coverage results in mcdc tests.
3. So far rustc does not call `CoverageInfoBuilderMethods::init_coverage` for inlined functions. As a result, it could panic if it tries to instrument mcdc statements for inlined functions due to uninitialized cond bitmaps. We can reproduce this issue by current nightly rustc and [the test](https://github.com/rust-lang/rust/pull/127234/files#diff-c81af6bf4869aa42f5c7334e3e86344475de362f673f54ce439ec75fcb5ac3e5) with flag `--release`. This patch fixes it.

1 files changed, 72 insertions, 0 deletions

diff --git a/tests/coverage/mcdc/non_control_flow.rs b/tests/coverage/mcdc/non_control_flow.rs
new file mode 100644
index 00000000000..77e64e6625b
--- /dev/null
+++ b/tests/coverage/mcdc/non_control_flow.rs
@@ -0,0 +1,72 @@
+#![feature(coverage_attribute)]
+//@ edition: 2021
+//@ min-llvm-version: 18
+//@ compile-flags: -Zcoverage-options=mcdc
+//@ llvm-cov-flags: --show-branches=count --show-mcdc
+
+// This test ensures that boolean expressions that are not inside control flow
+// decisions are correctly instrumented.
+
+use core::hint::black_box;
+
+fn assign_and(a: bool, b: bool) {
+    let x = a && b;
+    black_box(x);
+}
+
+fn assign_or(a: bool, b: bool) {
+    let x = a || b;
+    black_box(x);
+}
+
+fn assign_3(a: bool, b: bool, c: bool) {
+    let x = a || b && c;
+    black_box(x);
+}
+
+fn assign_3_bis(a: bool, b: bool, c: bool) {
+    let x = a && b || c;
+    black_box(x);
+}
+
+fn right_comb_tree(a: bool, b: bool, c: bool, d: bool, e: bool) {
+    let x = a && (b && (c && (d && (e))));
+    black_box(x);
+}
+
+fn foo(a: bool) -> bool {
+    black_box(a)
+}
+
+fn func_call(a: bool, b: bool) {
+    foo(a && b);
+}
+
+#[coverage(off)]
+fn main() {
+    assign_and(true, false);
+    assign_and(true, true);
+    assign_and(false, false);
+
+    assign_or(true, false);
+    assign_or(true, true);
+    assign_or(false, false);
+
+    assign_3(true, false, false);
+    assign_3(true, true, false);
+    assign_3(false, false, true);
+    assign_3(false, true, true);
+
+    assign_3_bis(true, false, false);
+    assign_3_bis(true, true, false);
+    assign_3_bis(false, false, true);
+    assign_3_bis(false, true, true);
+
+    right_comb_tree(false, false, false, true, true);
+    right_comb_tree(true, false, false, true, true);
+    right_comb_tree(true, true, true, true, true);
+
+    func_call(true, false);
+    func_call(true, true);
+    func_call(false, false);
+}