[SystemZ] Improve decoding in case of instructions with four register operands.

Since z13, the max group size will be 2 if any μop has more than 3 register
sources.

This has been ignored sofar in the SystemZHazardRecognizer, but is now
handled by recognizing those instructions and adjusting the tracking of
decoding and the cost heuristic for grouping.

Review: Ulrich Weigand
https://reviews.llvm.org/D49847

llvm-svn: 338368

1 files changed, 1 insertions, 2 deletions

diff --git a/llvm/lib/Target/SystemZ/SystemZMachineScheduler.cpp b/llvm/lib/Target/SystemZ/SystemZMachineScheduler.cpp
index 11e60158524..98e761ef87f 100644
--- a/llvm/lib/Target/SystemZ/SystemZMachineScheduler.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZMachineScheduler.cpp
@@ -169,8 +169,7 @@ SUnit *SystemZPostRASchedStrategy::pickNode(bool &IsTopNode) {
     return *Available.begin();
   }
 
-  // All nodes that are possible to schedule are stored by in the
-  // Available set.
+  // All nodes that are possible to schedule are stored in the Available set.
   LLVM_DEBUG(dbgs() << "** Available: "; Available.dump(*HazardRec););
 
   Candidate Best;