[llvm] r187475 - Fix a severe compile time problem when forming large SCEV expressions.

[Andrew Trick]

Author: atrick
Date: Tue Jul 30 21:43:40 2013
New Revision: 187475

URL: http://llvm.org/viewvc/llvm-project?rev=187475&view=rev
Log:
Fix a severe compile time problem when forming large SCEV expressions.

This fix is very lightweight. The same fix already existed for AddRec
but was missing for NAry expressions.

This is obviously an improvement and I'm unsure how to test compile
time problems.

Patch by Xiaoyi Guo!

Modified:
    llvm/trunk/lib/Analysis/ScalarEvolution.cpp

Modified: llvm/trunk/lib/Analysis/ScalarEvolution.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolution.cpp?rev=187475&r1=187474&r2=187475&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Tue Jul 30 21:43:40 2013
@@ -585,6 +585,9 @@ namespace {
 
         // Lexicographically compare n-ary expressions.
         unsigned LNumOps = LC->getNumOperands(), RNumOps = RC->getNumOperands();
+        if (LNumOps != RNumOps)
+          return (int)LNumOps - (int)RNumOps;
+
         for (unsigned i = 0; i != LNumOps; ++i) {
           if (i >= RNumOps)
             return 1;