Make assert_instr stricter

Author: sayantn

crates/stdarch-test/src/disassembly.rs

@@ -150,7 +150,7 @@ fn parse(output: &str) -> HashSet<Function> {
                 instruction
                     .split_whitespace()
                     .skip(1)
-                    .skip_while(|s| *s == "lock" || *s == "{evex}") // skip x86-specific prefix
+                    .skip_while(|s| *s == "lock" || *s == "{evex}" || *s == "{vex}") // skip x86-specific prefix
                     .map(std::string::ToString::to_string)
                     .collect::<Vec<String>>()
             };

crates/stdarch-test/src/lib.rs

@@ -84,7 +84,9 @@ pub fn assert(shim_addr: usize, fnname: &str, expected: &str) {
     // 2. It is a mark, indicating that the instruction will be
     // compiled into other instructions - mainly because of llvm
     // optimization.
-    let found = expected == "nop" || instrs.iter().any(|s| s.contains(expected));
+    let found = expected == "nop"
+        || instrs.iter().any(|s| s.starts_with(expected))
+        || (expected == "unknown" && instrs.iter().any(|s| s.starts_with("<unknown>"))); // Workaround for rust-lang/stdarch#1674
 
     // Look for subroutine call instructions in the disassembly to detect whether
     // inlining failed: all intrinsics are `#[inline(always)]`, so calling one