[MachineScheduler] Add support for clustering mem ops with FI base operands

Before this patch, the following stores in `merge_fail` would fail to be
merged, while they would get merged in `merge_ok`:

```
void use(unsigned long long *);
void merge_fail(unsigned key, unsigned index)
{
  unsigned long long args[8];
  args[0] = key;
  args[1] = index;
  use(args);
}
void merge_ok(unsigned long long *dst, unsigned a, unsigned b)
{
  dst[0] = a;
  dst[1] = b;
}
```

The reason is that `getMemOpBaseImmOfs` would return false for FI base
operands.

This adds support for this.

Differential Revision: https://reviews.llvm.org/D54847

llvm-svn: 347747

1 files changed, 14 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/MachineScheduler.cpp b/llvm/lib/CodeGen/MachineScheduler.cpp
index e423c89b1db..7313d43c806 100644
--- a/llvm/lib/CodeGen/MachineScheduler.cpp
+++ b/llvm/lib/CodeGen/MachineScheduler.cpp
@@ -1490,8 +1490,20 @@ class BaseMemOpClusterMutation : public ScheduleDAGMutation {
         : SU(su), BaseOp(Op), Offset(ofs) {}
 
     bool operator<(const MemOpInfo &RHS) const {
-      return std::make_tuple(BaseOp->getReg(), Offset, SU->NodeNum) <
-             std::make_tuple(RHS.BaseOp->getReg(), RHS.Offset, RHS.SU->NodeNum);
+      if (BaseOp->getType() != RHS.BaseOp->getType())
+        return BaseOp->getType() < RHS.BaseOp->getType();
+
+      if (BaseOp->isReg())
+        return std::make_tuple(BaseOp->getReg(), Offset, SU->NodeNum) <
+               std::make_tuple(RHS.BaseOp->getReg(), RHS.Offset,
+                               RHS.SU->NodeNum);
+      if (BaseOp->isFI())
+        return std::make_tuple(BaseOp->getIndex(), Offset, SU->NodeNum) <
+               std::make_tuple(RHS.BaseOp->getIndex(), RHS.Offset,
+                               RHS.SU->NodeNum);
+
+      llvm_unreachable("MemOpClusterMutation only supports register or frame "
+                       "index bases.");
     }
   };