Switch the comment syntax from ; to // comments as discussed on Friday.  There
is no strong reason to prefer one or the other, but // is nice for consistency
given the rest of the compiler is written in C++.

PiperOrigin-RevId: 204628476
diff --git a/test/IR/parser-errors.mlir b/test/IR/parser-errors.mlir
index ff3906a..27a53bd 100644
--- a/test/IR/parser-errors.mlir
+++ b/test/IR/parser-errors.mlir
@@ -1,107 +1,107 @@
-; TODO(andydavis) Resolve relative path issue w.r.t invoking mlir-opt in RUN
-; statements (perhaps through using lit config substitutions).
-;
-; RUN: %S/../../mlir-opt %s -o - -check-parser-errors
+// TODO(andydavis) Resolve relative path issue w.r.t invoking mlir-opt in RUN
+// statements (perhaps through using lit config substitutions).
+//
+// RUN: %S/../../mlir-opt %s -o - -check-parser-errors
 
-; Check different error cases.
-; -----
+// Check different error cases.
+// -----
 
-extfunc @illegaltype(i) ; expected-error {{expected type}}
+extfunc @illegaltype(i) // expected-error {{expected type}}
 
-; -----
+// -----
 
-extfunc @nestedtensor(tensor<tensor<i8>>) -> () ; expected-error {{expected type}}
+extfunc @nestedtensor(tensor<tensor<i8>>) -> () // expected-error {{expected type}}
 
-; -----
+// -----
 
 cfgfunc @foo()
-cfgfunc @bar() ; expected-error {{expected '{' in CFG function}}
+cfgfunc @bar() // expected-error {{expected '{' in CFG function}}
 
-; -----
+// -----
 
-extfunc missingsigil() -> (i1, affineint, f32) ; expected-error {{expected a function identifier like}}
+extfunc missingsigil() -> (i1, affineint, f32) // expected-error {{expected a function identifier like}}
 
 
-; -----
+// -----
 
 cfgfunc @bad_branch() {
 bb42:
-  br missing  ; expected-error {{reference to an undefined basic block 'missing'}}
+  br missing  // expected-error {{reference to an undefined basic block 'missing'}}
 }
 
-; -----
+// -----
 
 cfgfunc @block_redef() {
 bb42:
   return
-bb42:        ; expected-error {{redefinition of block 'bb42'}}
+bb42:        // expected-error {{redefinition of block 'bb42'}}
   return
 }
 
-; -----
+// -----
 
 cfgfunc @no_terminator() {
 bb40:
   return
 bb41:
-bb42:        ; expected-error {{expected operation name}}
+bb42:        // expected-error {{expected operation name}}
   return
 }
 
-; -----
+// -----
 
 mlfunc @foo()
-mlfunc @bar() ; expected-error {{expected '{' in ML function}}
+mlfunc @bar() // expected-error {{expected '{' in ML function}}
 
-; -----
+// -----
 
 mlfunc @no_return() {
-}        ; expected-error {{ML function must end with return statement}}
+}        // expected-error {{ML function must end with return statement}}
 
-; -----
+// -----
 
-"       ; expected-error {{expected}}
+"       // expected-error {{expected}}
 "
 
-; -----
+// -----
 
-"       ; expected-error {{expected}}
+"       // expected-error {{expected}}
 
-; -----
+// -----
 
 cfgfunc @no_terminator() {
 bb40:
   "foo"()
-  ""()   ; expected-error {{empty operation name is invalid}}
+  ""()   // expected-error {{empty operation name is invalid}}
   return
 }
 
-; -----
+// -----
 
-extfunc @illegaltype(i0) ; expected-error {{invalid integer width}}
+extfunc @illegaltype(i0) // expected-error {{invalid integer width}}
 
-; -----
+// -----
 
 mlfunc @incomplete_for() {
   for
-}        ; expected-error {{expected '{' before statement list}}
+}        // expected-error {{expected '{' before statement list}}
 
-; -----
+// -----
 
 mlfunc @non_statement() {
-  asd   ; expected-error {{expected statement}}
+  asd   // expected-error {{expected statement}}
 }
 
-; -----
+// -----
 
 cfgfunc @malformed_dim() {
 bb42:
-  "dim"(){index: "xyz"}  ; expected-error {{'dim' op requires an integer attribute named 'index'}}
+  "dim"(){index: "xyz"}  // expected-error {{'dim' op requires an integer attribute named 'index'}}
   return
 }
 
-; -----
+// -----
 
-#map = (d0) -> (%  ; expected-error {{invalid SSA name}}
+#map = (d0) -> (%  // expected-error {{invalid SSA name}}
 
-; -----
+// -----