[clang-tidy] Speedup misc-static-assert.

[sbenza]

Summary

Speedup the misc-static-assert check by not use stmt() as the toplevel matcher.
The framework runs a filter on the matchers before trying them on each node and
uses the toplevel type for this.
Using stmt() as the toplevel causes the matcher to be run on every Stmt node,
even if the node doesn't match the desired types.

This change speeds up clang-tidy by ~5% in a benchmark.

[aaron.ballman]

LGTM, thank you for noticing that!

[alexfh]

Thank you for finding and fixing this! I think I used to suggest the wrong pattern, now I won't.

clang-tools-extra/trunk/clang-tidy/misc/StaticAssertCheck.cpp

auto AssertCondition =
           unless(findAll(NonConstexprFunctionCall)))
           .bind("condition");
   auto Condition =
       anyOf(ignoringParenImpCasts(callExpr(
                 hasDeclaration(functionDecl(hasName("__builtin_expect"))),
                 hasArgument(0, AssertCondition))),
             AssertCondition);
 
-  Finder->addMatcher(stmt(anyOf(conditionalOperator(hasCondition(Condition)),
-                                ifStmt(hasCondition(Condition))),
+  Finder->addMatcher(conditionalOperator(hasCondition(Condition),
                                          unless(isInTemplateInstantiation()))
                          .bind("condStmt"),
                      this);
+
+  Finder->addMatcher(
+      ifStmt(hasCondition(Condition), unless(isInTemplateInstantiation()))
+          .bind("condStmt"),
+      this);
 }
 
 void StaticAssertCheck::check(const MatchFinder::MatchResult &Result) {
   const ASTContext *ASTCtx = Result.Context;
   const LangOptions &Opts = ASTCtx->getLangOpts();
   const SourceManager &SM = ASTCtx->getSourceManager();
   const auto *CondStmt = Result.Nodes.getNodeAs<Stmt>("condStmt");
   const auto *Condition = Result.Nodes.getNodeAs<Expr>("condition");