[llvm-commits] [llvm] r122844 - /llvm/trunk/lib/Transforms/Scalar/GVN.cpp

[Owen Anderson]

Author: resistor
Date: Tue Jan  4 16:15:21 2011
New Revision: 122844

URL: http://llvm.org/viewvc/llvm-project?rev=122844&view=rev
Log:
Don't bother value numbering instructions with void types in GVN. In theory this should allow us to insert
fewer things into the value numbering maps, but any speedup is beneath the noise threshold on my machine
on 403.gcc.

Modified:
    llvm/trunk/lib/Transforms/Scalar/GVN.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/GVN.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/GVN.cpp?rev=122844&r1=122843&r2=122844&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/GVN.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/GVN.cpp Tue Jan  4 16:15:21 2011
@@ -1685,6 +1685,10 @@
     return false;
   }
   
+  // Instructions with void type don't return a value, so there's
+  // no point in trying to find redudancies in them.
+  if (I->getType()->isVoidTy()) return false;
+  
   uint32_t NextNum = VN.getNextUnusedValueNumber();
   unsigned Num = VN.lookup_or_add(I);