[llvm-commits] [llvm] r157161 - /llvm/trunk/lib/TableGen/StringMatcher.cpp

[Benjamin Kramer]

Author: d0k
Date: Sun May 20 13:10:42 2012
New Revision: 157161

URL: http://llvm.org/viewvc/llvm-project?rev=157161&view=rev
Log:
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.

Modified:
    llvm/trunk/lib/TableGen/StringMatcher.cpp

Modified: llvm/trunk/lib/TableGen/StringMatcher.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/TableGen/StringMatcher.cpp?rev=157161&r1=157160&r2=157161&view=diff
==============================================================================
--- llvm/trunk/lib/TableGen/StringMatcher.cpp (original)
+++ llvm/trunk/lib/TableGen/StringMatcher.cpp Sun May 20 13:10:42 2012
@@ -87,11 +87,11 @@
       << 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";
     }