tidy: wrap regexes with lazy_static

yes, once_cell better, but ...

this reduces from

==31349== Total:     1,365,199,543 bytes in 4,774,213 blocks
==31349== At t-gmax: 10,975,708 bytes in 66,093 blocks
==31349== At t-end:  2,880,947 bytes in 12,332 blocks
==31349== Reads:     5,210,008,956 bytes
==31349== Writes:    1,280,920,127 bytes

to

==47796== Total:     821,467,407 bytes in 3,955,595 blocks
==47796== At t-gmax: 10,976,209 bytes in 66,100 blocks
==47796== At t-end:  2,944,016 bytes in 12,490 blocks
==47796== Reads:     4,788,959,023 bytes
==47796== Writes:    975,493,639 bytes

miropt-test-tools: remove regex usage

this removes regex usage and slightly refactors ext stripping in one case

Cargo.lock

@@ -2490,9 +2490,6 @@ dependencies = [
 [[package]]
 name = "miropt-test-tools"
 version = "0.1.0"
-dependencies = [
- "regex",
-]
 
 [[package]]
 name = "native-tls"

src/tools/miropt-test-tools/Cargo.toml

@@ -4,4 +4,3 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
-regex = "1.0"

src/tools/miropt-test-tools/src/lib.rs

@@ -100,14 +100,19 @@ pub fn files_for_miropt_test(
             } else {
                 // Allow-list for file extensions that can be produced by MIR dumps.
                 // Other extensions can be added here, as needed by new dump flags.
-                let ext_re = regex::Regex::new(r#"(\.(mir|dot))$"#).unwrap();
-                let cap = ext_re.captures_iter(test_name).next().unwrap_or_else(|| {
-                    panic!("in {testfile:?}:\nEMIT_MIR has an unrecognized extension: {test_name}")
-                });
-                let extension = cap.get(1).unwrap().as_str();
+                static ALLOWED_EXT: &[&str] = &["mir", "dot"];
+                let Some((test_name_wo_ext, test_name_ext)) = test_name.rsplit_once('.') else {
+                    panic!(
+                        "in {testfile:?}:\nEMIT_MIR has an unrecognized extension: {test_name}, expected one of {ALLOWED_EXT:?}"
+                    )
+                };
+                if !ALLOWED_EXT.contains(&test_name_ext) {
+                    panic!(
+                        "in {testfile:?}:\nEMIT_MIR has an unrecognized extension: {test_name}, expected one of {ALLOWED_EXT:?}"
+                    )
+                }
 
-                expected_file =
-                    format!("{}{}{}", test_name.trim_end_matches(extension), suffix, extension,);
+                expected_file = format!("{}{}.{}", test_name_wo_ext, suffix, test_name_ext);
                 from_file = test_name.to_string();
                 assert!(test_names.next().is_none(), "two mir pass names specified for MIR dump");
                 to_file = None;

src/tools/tidy/src/style.rs

@@ -127,8 +127,10 @@ fn should_ignore(line: &str) -> bool {
     // Matches test annotations like `//~ ERROR text`.
     // This mirrors the regex in src/tools/compiletest/src/runtest.rs, please
     // update both if either are changed.
-    let re = Regex::new("\\s*//(\\[.*\\])?~.*").unwrap();
-    re.is_match(line) || ANNOTATIONS_TO_IGNORE.iter().any(|a| line.contains(a))
+    lazy_static::lazy_static! {
+        static ref ANNOTATION_RE: Regex = Regex::new("\\s*//(\\[.*\\])?~.*").unwrap();
+    }
+    ANNOTATION_RE.is_match(line) || ANNOTATIONS_TO_IGNORE.iter().any(|a| line.contains(a))
 }
 
 /// Returns `true` if `line` is allowed to be longer than the normal limit.