From: Jakob Stoklund Olesen <stoklund@2pi.dk>
Date: Tue, 8 Feb 2011 19:33:55 +0000 (+0000)
Subject: Avoid folding a load instruction into an instruction that redefines the register.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=7b1f498a7648b790929a4f97fd82228aa7ac7bea;p=llvm

Avoid folding a load instruction into an instruction that redefines the register.

The target hook doesn't know how to do that. (Neither do I).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125108 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/InlineSpiller.cpp b/lib/CodeGen/InlineSpiller.cpp
index 3e4f6c83036..00ca3d5bb64 100644
--- a/lib/CodeGen/InlineSpiller.cpp
+++ b/lib/CodeGen/InlineSpiller.cpp
@@ -157,7 +157,8 @@ bool InlineSpiller::reMaterializeFor(MachineBasicBlock::iterator MI) {
   // Finally we can rematerialize OrigMI before MI.
   SlotIndex DefIdx = edit_->rematerializeAt(*MI->getParent(), MI, NewLI.reg, RM,
                                             lis_, tii_, tri_);
-  DEBUG(dbgs() << "\tremat:  " << DefIdx << '\n');
+  DEBUG(dbgs() << "\tremat:  " << DefIdx << '\t'
+               << *lis_.getInstructionFromIndex(DefIdx));
 
   // Replace operands
   for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
@@ -270,6 +271,9 @@ bool InlineSpiller::foldMemoryOperand(MachineBasicBlock::iterator MI,
     // FIXME: Teach targets to deal with subregs.
     if (MO.getSubReg())
       return false;
+    // We cannot fold a load instruction into a def.
+    if (LoadMI && MO.isDef())
+      return false;
     // Tied use operands should not be passed to foldMemoryOperand.
     if (!MI->isRegTiedToDefOperand(Idx))
       FoldOps.push_back(Idx);