From 0272be206a0d1369736dfee456bfa7430ccd5e02 Mon Sep 17 00:00:00 2001
From: Sanjoy Das <sanjoy@playingwithpointers.com>
Date: Wed, 15 Jun 2016 05:35:14 +0000
Subject: Don't force SP-relative addressing for statepoints

Summary:
...  when the offset is not statically known.

Prioritize addresses relative to the stack pointer in the stackmap, but
fallback gracefully to other modes of addressing if the offset to the
stack pointer is not a known constant.

Patch by Oscar Blumberg!

Reviewers: sanjoy

Subscribers: llvm-commits, majnemer, rnk, sanjoy, thanm

Differential Revision: http://reviews.llvm.org/D21259

llvm-svn: 272756
---
 llvm/lib/CodeGen/PrologEpilogInserter.cpp | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

(limited to 'llvm/lib/CodeGen/PrologEpilogInserter.cpp')

diff --git a/llvm/lib/CodeGen/PrologEpilogInserter.cpp b/llvm/lib/CodeGen/PrologEpilogInserter.cpp
index bd7f34b..33935c42 100644
--- a/llvm/lib/CodeGen/PrologEpilogInserter.cpp
+++ b/llvm/lib/CodeGen/PrologEpilogInserter.cpp
@@ -1094,9 +1094,16 @@ void PEI::replaceFrameIndices(MachineBasicBlock *BB, MachineFunction &Fn,
                "DBG_VALUE machine instruction");
         unsigned Reg;
         MachineOperand &Offset = MI->getOperand(i + 1);
-        const unsigned refOffset =
-          TFI->getFrameIndexReferenceFromSP(Fn, MI->getOperand(i).getIndex(),
-                                            Reg);
+        int refOffset;
+        // First try to get an offset relative to SP. If that's not
+        // possible use whatever the target usually uses.
+        auto SPOffset = TFI->getFrameIndexReferenceFromSP(
+            Fn, MI->getOperand(i).getIndex(), Reg, /*AllowSPAdjustment*/ false);
+        if (SPOffset)
+          refOffset = *SPOffset;
+        else
+          refOffset = TFI->getFrameIndexReference(
+              Fn, MI->getOperand(i).getIndex(), Reg);
 
         Offset.setImm(Offset.getImm() + refOffset);
         MI->getOperand(i).ChangeToRegister(Reg, false /*isDef*/);
-- 
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