Emit memcmp directly from the StringMatcherEmitter.

There should be no difference in the resulting binary, given a sufficiently
smart compiler. However we already had compiler timeouts on the generated
code in Intrinsics.gen, this hopefully makes the lives of slow buildbots a
little easier.

llvm-svn: 157161

1 files changed, 4 insertions, 4 deletions

diff --git a/llvm/lib/TableGen/StringMatcher.cpp b/llvm/lib/TableGen/StringMatcher.cpp
index 0ce626d4b19..16681702d1d 100644
--- a/llvm/lib/TableGen/StringMatcher.cpp
+++ b/llvm/lib/TableGen/StringMatcher.cpp
@@ -87,11 +87,11 @@ EmitStringMatcherForChar(const std::vector<const StringPair*> &Matches,
       << Matches[0]->first[CharNo] << "')\n";
       OS << Indent << "  break;\n";
     } else {
-      // Do the comparison with if (Str.substr(1, 3) != "foo").    
+      // Do the comparison with if memcmp(Str.data()+1, "foo", 3).
       // FIXME: Need to escape general strings.
-      OS << Indent << "if (" << StrVariableName << ".substr(" << CharNo << ", "
-      << NumChars << ") != \"";
-      OS << Matches[0]->first.substr(CharNo, NumChars) << "\")\n";
+      OS << Indent << "if (memcmp(" << StrVariableName << ".data()+" << CharNo
+         << ", \"" << Matches[0]->first.substr(CharNo, NumChars) << "\", "
+         << NumChars << "))\n";
       OS << Indent << "  break;\n";
     }