From: Evan Cheng <evan.cheng@apple.com>
Date: Fri, 30 Jul 2010 23:33:54 +0000 (+0000)
Subject: Add -disable-shifter-op to disable isel of shifter ops. On Cortex-a9 the shifts cost... 
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a2c519bd0bdb19d4bb1f2377fcf429653af95960;p=oota-llvm.git

Add -disable-shifter-op to disable isel of shifter ops. On Cortex-a9 the shifts cost extra instructions so it might be better to emit them separately to take advantage of dual-issues.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109934 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/ARM/ARMISelDAGToDAG.cpp b/lib/Target/ARM/ARMISelDAGToDAG.cpp
index c84d3ff8132..f4012c71d7e 100644
--- a/lib/Target/ARM/ARMISelDAGToDAG.cpp
+++ b/lib/Target/ARM/ARMISelDAGToDAG.cpp
@@ -36,6 +36,11 @@
 
 using namespace llvm;
 
+static cl::opt<bool>
+DisableShifterOp("disable-shifter-op", cl::Hidden,
+  cl::desc("Disable isel of shifter-op"),
+  cl::init(false));
+
 //===--------------------------------------------------------------------===//
 /// ARMDAGToDAGISel - ARM specific code to select ARM machine
 /// instructions for SelectionDAG operations.
@@ -220,6 +225,9 @@ bool ARMDAGToDAGISel::SelectShifterOperandReg(SDNode *Op,
                                               SDValue &BaseReg,
                                               SDValue &ShReg,
                                               SDValue &Opc) {
+  if (DisableShifterOp)
+    return false;
+
   ARM_AM::ShiftOpc ShOpcVal = ARM_AM::getShiftOpcForNode(N);
 
   // Don't match base register only case. That is matched to a separate
@@ -666,6 +674,9 @@ bool ARMDAGToDAGISel::SelectThumbAddrModeSP(SDNode *Op, SDValue N,
 bool ARMDAGToDAGISel::SelectT2ShifterOperandReg(SDNode *Op, SDValue N,
                                                 SDValue &BaseReg,
                                                 SDValue &Opc) {
+  if (DisableShifterOp)
+    return false;
+
   ARM_AM::ShiftOpc ShOpcVal = ARM_AM::getShiftOpcForNode(N);
 
   // Don't match base register only case. That is matched to a separate