commit d9bf71fdd26475f4629ef8861debfd2c621a372f
author Owen Anderson <resistor@mac.com> Mon Jul 09 20:31:12 2012 +0000
committer Owen Anderson <resistor@mac.com> Mon Jul 09 20:31:12 2012 +0000
tree 6e797d4b8428dc76be7375412b7a1e74a103492f
parent 6209364834a4c0ca720d3fcc9ef7fa4c1fb39ecc

Teach the DAG combiner to turn sitofp/uitofp from i1 into a conditional move, since there are only two possible values.
Previously, this would become an integer extension operation, followed by a real integer->float conversion.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159957 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/SelectionDAG/DAGCombiner.cpp

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 28c3be9..0287786 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -5974,6 +5974,30 @@
       return DAG.getNode(ISD::UINT_TO_FP, N->getDebugLoc(), VT, N0);
   }
 
+  // fold (sint_to_fp (setcc x, y, cc)) -> (select_cc x, y, -1.0, 0.0,, cc)
+  if (N0.getOpcode() == ISD::SETCC && !VT.isVector() &&
+      (!LegalOperations ||
+       TLI.isOperationLegalOrCustom(llvm::ISD::ConstantFP, VT))) {
+    SDValue Ops[] =
+      { N0.getOperand(0), N0.getOperand(1),
+        DAG.getConstantFP(-1.0, VT) , DAG.getConstantFP(0.0, VT),
+        N0.getOperand(2) };
+    return DAG.getNode(ISD::SELECT_CC, N->getDebugLoc(), VT, Ops, 5);
+  }
+
+  // fold (sint_to_fp (zext (setcc x, y, cc))) ->
+  //      (select_cc x, y, 1.0, 0.0,, cc)
+  if (N0.getOpcode() == ISD::ZERO_EXTEND &&
+      N0.getOperand(0).getOpcode() == ISD::SETCC &&!VT.isVector() &&
+      (!LegalOperations ||
+       TLI.isOperationLegalOrCustom(llvm::ISD::ConstantFP, VT))) {
+    SDValue Ops[] =
+      { N0.getOperand(0).getOperand(0), N0.getOperand(0).getOperand(1),
+        DAG.getConstantFP(1.0, VT) , DAG.getConstantFP(0.0, VT),
+        N0.getOperand(0).getOperand(2) };
+    return DAG.getNode(ISD::SELECT_CC, N->getDebugLoc(), VT, Ops, 5);
+  }
+
   return SDValue();
 }
 
@@ -5999,6 +6023,18 @@
       return DAG.getNode(ISD::SINT_TO_FP, N->getDebugLoc(), VT, N0);
   }
 
+  // fold (uint_to_fp (setcc x, y, cc)) -> (select_cc x, y, -1.0, 0.0,, cc)
+  if (N0.getOpcode() == ISD::SETCC && !VT.isVector() &&
+      (!LegalOperations ||
+       TLI.isOperationLegalOrCustom(llvm::ISD::ConstantFP, VT))) {
+    SDValue Ops[] =
+      { N0.getOperand(0), N0.getOperand(1),
+        DAG.getConstantFP(1.0, VT),  DAG.getConstantFP(0.0, VT),
+        N0.getOperand(2) };
+    return DAG.getNode(ISD::SELECT_CC, N->getDebugLoc(), VT, Ops, 5);
+  }
+
+
   return SDValue();
 }