From 2c987c32ffee90827faa69f4cf2f01478c9f617a Mon Sep 17 00:00:00 2001
From: Chris Lattner <clattner@nondot.org>
Date: Wed, 8 Apr 2020 10:40:50 -0700
Subject: [PATCH] Fix a super subtle bug: we were strlen'ing the entire buffer
 every time we returned an lp_ keyword, which is N^2 work with a very large N
 (particularly when your testcase is half a megabyte of .fir)!

This speeds up the parser from 12.75s -> 0.09s (!!!), which feels better
to me :)
---
 lib/Dialect/FIRRTL/FIRToMLIR/FIRLexer.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/Dialect/FIRRTL/FIRToMLIR/FIRLexer.cpp b/lib/Dialect/FIRRTL/FIRToMLIR/FIRLexer.cpp
index 3f1d13f5e70d..25343173d8ba 100644
--- a/lib/Dialect/FIRRTL/FIRToMLIR/FIRLexer.cpp
+++ b/lib/Dialect/FIRRTL/FIRToMLIR/FIRLexer.cpp
@@ -246,7 +246,7 @@ FIRToken FIRLexer::lexIdentifierOrKeyword(const char *tokStart) {
                               .Default(FIRToken::identifier);
     if (kind != FIRToken::identifier) {
       ++curPtr;
-      return FIRToken(kind, tokStart);
+      return formToken(kind, tokStart);
     }
   }