Change the definition of TargetRegisterInfo::getCrossCopyRegClass to be more
flexible.
If it returns a register class that's different from the input, then that's the
register class used for cross-register class copies.
If it returns a register class that's the same as the input, then no cross-
register class copies are needed (normal copies would do).
If it returns null, then it's not at all possible to copy registers of the
specified register class.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127368 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp
index e3da208..7b560d1 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp
@@ -570,13 +570,20 @@
TRI->getMinimalPhysRegClass(Reg, VT);
const TargetRegisterClass *DestRC = TRI->getCrossCopyRegClass(RC);
- // If cross copy register class is null, then it must be possible copy
- // the value directly. Do not try duplicate the def.
+ // If cross copy register class is the same as RC, then it must be
+ // possible copy the value directly. Do not try duplicate the def.
+ // If cross copy register class is not the same as RC, then it's
+ // possible to copy the value but it require cross register class copies
+ // and it is expensive.
+ // If cross copy register class is null, then it's not possible to copy
+ // the value at all.
SUnit *NewDef = 0;
- if (DestRC)
+ if (DestRC != RC) {
NewDef = CopyAndMoveSuccessors(LRDef);
- else
- DestRC = RC;
+ if (!DestRC && !NewDef)
+ report_fatal_error("Can't handle live physical "
+ "register dependency!");
+ }
if (!NewDef) {
// Issue copies, these can be expensive cross register class copies.
SmallVector<SUnit*, 2> Copies;
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
index f1a5a65..5e60aa0 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
@@ -1140,13 +1140,19 @@
TRI->getMinimalPhysRegClass(Reg, VT);
const TargetRegisterClass *DestRC = TRI->getCrossCopyRegClass(RC);
- // If cross copy register class is null, then it must be possible copy
- // the value directly. Do not try duplicate the def.
+ // If cross copy register class is the same as RC, then it must be possible
+ // copy the value directly. Do not try duplicate the def.
+ // If cross copy register class is not the same as RC, then it's possible to
+ // copy the value but it require cross register class copies and it is
+ // expensive.
+ // If cross copy register class is null, then it's not possible to copy
+ // the value at all.
SUnit *NewDef = 0;
- if (DestRC)
+ if (DestRC != RC) {
NewDef = CopyAndMoveSuccessors(LRDef);
- else
- DestRC = RC;
+ if (!DestRC && !NewDef)
+ report_fatal_error("Can't handle live physical register dependency!");
+ }
if (!NewDef) {
// Issue copies, these can be expensive cross register class copies.
SmallVector<SUnit*, 2> Copies;