commit a414f36ad4dca3554e1313a4715b3856ac4066b9
author Anton Korobeynikov <asl@math.spbu.ru> Tue Nov 24 00:44:37 2009 +0000
committer Anton Korobeynikov <asl@math.spbu.ru> Tue Nov 24 00:44:37 2009 +0000
tree 6cbd9b033b162075d09d6815be1c15f65f1bd468
parent 71465ac298b594109d9f6e9c8b4fc97051840a8b

Materialize global addresses via movt/movw pair, this is always better
than doing the same via constpool:
1. Load from constpool costs 3 cycles on A9, movt/movw pair - just 2.
2. Load from constpool might stall up to 300 cycles due to cache miss.
3. Movt/movw does not use load/store unit.
4. Less constpool entries => better compiler performance.

This is only enabled on ELF systems, since darwin does not have needed
relocations (yet).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89720 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/ARM/ARMISelDAGToDAG.cpp

diff --git a/lib/Target/ARM/ARMISelDAGToDAG.cpp b/lib/Target/ARM/ARMISelDAGToDAG.cpp
index c7a50ed..d63f3e6 100644
--- a/lib/Target/ARM/ARMISelDAGToDAG.cpp
+++ b/lib/Target/ARM/ARMISelDAGToDAG.cpp
@@ -261,7 +261,9 @@
     if (N.getOpcode() == ISD::FrameIndex) {
       int FI = cast<FrameIndexSDNode>(N)->getIndex();
       Base = CurDAG->getTargetFrameIndex(FI, TLI.getPointerTy());
-    } else if (N.getOpcode() == ARMISD::Wrapper) {
+    } else if (N.getOpcode() == ARMISD::Wrapper &&
+               !(Subtarget->useMovt() &&
+                 N.getOperand(0).getOpcode() == ISD::TargetGlobalAddress)) {
       Base = N.getOperand(0);
     }
     Offset = CurDAG->getRegister(0, MVT::i32);
@@ -463,7 +465,9 @@
     if (N.getOpcode() == ISD::FrameIndex) {
       int FI = cast<FrameIndexSDNode>(N)->getIndex();
       Base = CurDAG->getTargetFrameIndex(FI, TLI.getPointerTy());
-    } else if (N.getOpcode() == ARMISD::Wrapper) {
+    } else if (N.getOpcode() == ARMISD::Wrapper &&
+               !(Subtarget->useMovt() &&
+                 N.getOperand(0).getOpcode() == ISD::TargetGlobalAddress)) {
       Base = N.getOperand(0);
     }
     Offset = CurDAG->getTargetConstant(ARM_AM::getAM5Opc(ARM_AM::add, 0),
@@ -558,7 +562,13 @@
   }
 
   if (N.getOpcode() != ISD::ADD) {
-    Base = (N.getOpcode() == ARMISD::Wrapper) ? N.getOperand(0) : N;
+    if (N.getOpcode() == ARMISD::Wrapper &&
+        !(Subtarget->useMovt() &&
+          N.getOperand(0).getOpcode() == ISD::TargetGlobalAddress)) {
+      Base = N.getOperand(0);
+    } else
+      Base = N;
+
     Offset = CurDAG->getRegister(0, MVT::i32);
     OffImm = CurDAG->getTargetConstant(0, MVT::i32);
     return true;
@@ -681,7 +691,9 @@
       Base = CurDAG->getTargetFrameIndex(FI, TLI.getPointerTy());
       OffImm  = CurDAG->getTargetConstant(0, MVT::i32);
       return true;
-    } else if (N.getOpcode() == ARMISD::Wrapper) {
+    } else if (N.getOpcode() == ARMISD::Wrapper &&
+               !(Subtarget->useMovt() &&
+                 N.getOperand(0).getOpcode() == ISD::TargetGlobalAddress)) {
       Base = N.getOperand(0);
       if (Base.getOpcode() == ISD::TargetConstantPool)
         return false;  // We want to select t2LDRpci instead.