[llvm-commits] [llvm] r123515 - /llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp

[Chris Lattner]

Author: lattner
Date: Fri Jan 14 23:41:33 2011
New Revision: 123515

URL: http://llvm.org/viewvc/llvm-project?rev=123515&view=rev
Log:
Catch ~x < cst  just like ~x < ~y, we currently handle this through
means that are about to disappear.


Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp?rev=123515&r1=123514&r2=123515&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Fri Jan 14 23:41:33 2011
@@ -2284,11 +2284,15 @@
     }
   }
   
-  // ~x < ~y --> y < x
   { Value *A, *B;
-    if (match(Op0, m_Not(m_Value(A))) &&
-        match(Op1, m_Not(m_Value(B))))
-      return new ICmpInst(I.getPredicate(), B, A);
+    // ~x < ~y --> y < x
+    // ~x < cst --> ~cst < x
+    if (match(Op0, m_Not(m_Value(A)))) {
+      if (match(Op1, m_Not(m_Value(B))))
+        return new ICmpInst(I.getPredicate(), B, A);
+      if (ConstantInt *RHSC = dyn_cast<ConstantInt>(B))
+        return new ICmpInst(I.getPredicate(), ConstantExpr::getNot(RHSC), A);
+    }
 
     // (a+b) <u a  --> llvm.uadd.with.overflow.
     // (a+b) <u b  --> llvm.uadd.with.overflow.