From a3eeef82da8be7f2cfa6dc7bed0fe4c11d585180 Mon Sep 17 00:00:00 2001 From: Nikita Popov Date: Tue, 14 Nov 2023 09:03:54 +0100 Subject: [FileCheck] Avoid capturing group for {{regex}} (#72136) For `{{regex}}` we don't really need a capturing group, and only add it to properly handle cases like `{{foo|bar}}`. This is problematic, because the use of capturing groups makes our regex implementation slower (we have to go through the "dissect" stage, which can have quadratic complexity). Unfortunately, our regex implementation does not support non-capturing groups like `(?:regex)`. So instead, avoid adding the group entirely if the regex doesn't contain any alternations. This causes a slight difference in escaping behavior, where previously it was possible to write `{{{{}}` and get the same behavior as `{{\{\{}}`. This will no longer work. I don't think this is a problem, especially as we recently taught update_analyze_test_checks.py to emit `{{\{\{}}`, so this shouldn't get introduced in any new tests. For CodeGen/X86/vector-interleaved-store-i16-stride-7.ll (our slowest X86 test) this drops FileCheck time from 6s to 5s (the remainder is spent in a different regex issue). I expect similar speedups in other tests using a lot of `{{}}`. --- llvm/lib/FileCheck/FileCheck.cpp | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'llvm/lib/FileCheck/FileCheck.cpp') diff --git a/llvm/lib/FileCheck/FileCheck.cpp b/llvm/lib/FileCheck/FileCheck.cpp index 49fda8f..bef6dd6 100644 --- a/llvm/lib/FileCheck/FileCheck.cpp +++ b/llvm/lib/FileCheck/FileCheck.cpp @@ -832,12 +832,16 @@ bool Pattern::parsePattern(StringRef PatternStr, StringRef Prefix, // capturing the result for any purpose. This is required in case the // expression contains an alternation like: CHECK: abc{{x|z}}def. We // want this to turn into: "abc(x|z)def" not "abcx|zdef". - RegExStr += '('; - ++CurParen; + bool HasAlternation = PatternStr.contains('|'); + if (HasAlternation) { + RegExStr += '('; + ++CurParen; + } if (AddRegExToRegEx(PatternStr.substr(2, End - 2), CurParen, SM)) return true; - RegExStr += ')'; + if (HasAlternation) + RegExStr += ')'; PatternStr = PatternStr.substr(End + 2); continue; -- cgit v1.1