Rematerialization logic was overly conservative when it comes to loads from fixed stack slots.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47529 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index a18f36a..2ff8afd 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -646,27 +646,9 @@
int FrameIdx = 0;
if (tii_->isLoadFromStackSlot(MI, FrameIdx) &&
- mf_->getFrameInfo()->isImmutableObjectIndex(FrameIdx)) {
- // This is a load from fixed stack slot. It can be rematerialized unless
- // it's re-defined by a two-address instruction.
- isLoad = true;
- for (LiveInterval::const_vni_iterator i = li.vni_begin(), e = li.vni_end();
- i != e; ++i) {
- const VNInfo *VNI = *i;
- if (VNI == ValNo)
- continue;
- unsigned DefIdx = VNI->def;
- if (DefIdx == ~1U)
- continue; // Dead val#.
- MachineInstr *DefMI = (DefIdx == ~0u)
- ? NULL : getInstructionFromIndex(DefIdx);
- if (DefMI && DefMI->isRegReDefinedByTwoAddr(li.reg)) {
- isLoad = false;
- return false;
- }
- }
+ mf_->getFrameInfo()->isImmutableObjectIndex(FrameIdx))
+ // This is a load from fixed stack slot. It can be rematerialized.
return true;
- }
if (tii_->isTriviallyReMaterializable(MI)) {
isLoad = TID.isSimpleLoad();
@@ -754,6 +736,10 @@
FoldOps.push_back(OpIdx);
}
+ // Can't fold a load from fixed stack slot into a two address instruction.
+ if (isSS && DefMI && (MRInfo & VirtRegMap::isMod))
+ return false;
+
MachineInstr *fmi = isSS ? tii_->foldMemoryOperand(*mf_, MI, FoldOps, Slot)
: tii_->foldMemoryOperand(*mf_, MI, FoldOps, DefMI);
if (fmi) {