From: Jim Grosbach <grosbach@apple.com>
Date: Wed, 30 Sep 2009 01:43:29 +0000 (+0000)
Subject: When checking whether we need to reserve a register for the scavenger,
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=d1a5ca6cb11763059ba1ee1c965cc69abff92e38;p=oota-llvm.git

When checking whether we need to reserve a register for the scavenger,
the size of the saved frame pointer needs to be taken into account.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83136 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/ARM/ARMBaseRegisterInfo.cpp b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
index a7ab3b57da5..6086c1b4baa 100644
--- a/lib/Target/ARM/ARMBaseRegisterInfo.cpp
+++ b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
@@ -654,7 +654,13 @@ ARMBaseRegisterInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
     // adjustments also, even when the frame itself is small.
     if (RS && !ExtraCSSpill) {
       MachineFrameInfo  *MFI = MF.getFrameInfo();
-      if (estimateStackSize(MF, MFI) >= estimateRSStackSizeLimit(MF)
+      // If any of the stack slot references may be out of range of an
+      // immediate offset, make sure a register (or a spill slot) is
+      // available for the register scavenger. Note that if we're indexing
+      // off the frame pointer, the effective stack size is 4 bytes larger
+      // since the FP points to the previous FP.
+      if (estimateStackSize(MF, MFI) + (hasFP(MF) ? 4 : 0)
+          >= estimateRSStackSizeLimit(MF)
           || AFI->isThumb1OnlyFunction()) {
         // If any non-reserved CS register isn't spilled, just spill one or two
         // extra. That should take care of it!