From 3ecdfafe3b06844ab0412b48f6daedf3e13e7037 Mon Sep 17 00:00:00 2001 From: Owen Anderson Date: Sun, 18 Jul 2010 08:47:54 +0000 Subject: [PATCH] Add a DAGCombine xform to fold away redundant float->double->float conversions around sqrt instructions. I am assured by people more knowledgeable than me that there are no rounding issues in eliminating this. This fixed . git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108639 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index e6717524645..271b2b621d0 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -4926,6 +4926,19 @@ SDValue DAGCombiner::visitFP_ROUND(SDNode *N) { return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT, Tmp, N0.getOperand(1)); } + + // (f32 fp_round (f64 sqrt (f64 fp_extend (f32)))) -> (f32 sqrt) + EVT VT0 = N0.getValueType(); + if (VT == MVT::f32 && + N0.getOpcode() == ISD::FSQRT && VT0 == MVT::f64) { + SDValue N1 = N0.getOperand(0); + EVT VT1 = N1.getValueType(); + if (N1.getOpcode() == ISD::FP_EXTEND && VT1 == MVT::f64 && + N1.getOperand(0).getValueType() == MVT::f32) { + return DAG.getNode(ISD::FSQRT, N->getDebugLoc(), MVT::f32, + N1.getOperand(0), N->getOperand(1)); + } + } return SDValue(); }