[llvm-commits] CVS: llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

[Chris Lattner]

Changes in directory llvm/lib/CodeGen/SelectionDAG:

SelectionDAG.cpp updated: 1.92 -> 1.93
---
Log message:

Codegen x < 0 | y < 0 as (x|y) < 0.  This allows us to compile this to:

_foo:
        or r2, r4, r3
        srwi r3, r2, 31
        blr

instead of:

_foo:
        srwi r2, r4, 31
        srwi r3, r3, 31
        or r3, r2, r3
        blr



---
Diffs of the changes:  (+4 -1)

 SelectionDAG.cpp |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletion(-)


Index: llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
diff -u llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:1.92 llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:1.93
--- llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:1.92	Thu Apr 21 23:01:18 2005
+++ llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp	Mon Apr 25 16:03:25 2005
@@ -809,6 +809,7 @@
       return MaskedValueIsZero(Op.getOperand(0), NewVal, TLI);
     }
     return false;
+    // TODO we could handle some SRA cases here.
   default: break;
   }
 
@@ -1061,11 +1062,13 @@
 
         // (X != 0) | (Y != 0) -> (X|Y != 0)
         // (X == 0) & (Y == 0) -> (X|Y == 0)
+        // (X <  0) | (Y <  0) -> (X|Y < 0)
         if (LR == RR && isa<ConstantSDNode>(LR) &&
             cast<ConstantSDNode>(LR)->getValue() == 0 &&
             Op2 == LHS->getCondition() && MVT::isInteger(LL.getValueType())) {
           if ((Op2 == ISD::SETEQ && Opcode == ISD::AND) ||
-              (Op2 == ISD::SETNE && Opcode == ISD::OR))
+              (Op2 == ISD::SETNE && Opcode == ISD::OR) ||
+              (Op2 == ISD::SETLT && Opcode == ISD::OR))
             return getSetCC(Op2, VT,
                             getNode(ISD::OR, LR.getValueType(), LL, RL), LR);
         }