================
@@ -1326,6 +1326,69 @@ bool RegisterCoalescer::reMaterializeDef(const
CoalescerPair &CP,
if (!TII->isAsCheapAsAMove(*DefMI))
return false;
+ // Skip rematerialization for physical registers used as return values within
+ // the same basic block to enable better coalescing.
+ if (DstReg.isPhysical()) {
+ MachineBasicBlock *MBB = CopyMI->getParent();
+ if (DefMI->getParent() == MBB) {
+ // Check if there's already an identical instruction before CopyMI
+ // If so, allow rematerialization to avoid redundant instructions
+ bool FoundCopy = false;
+ for (MachineInstr &MI : *MBB) {
+ if (&MI == CopyMI) {
+ FoundCopy = true;
+ continue;
+ }
+
+ // Before CopyMI: check for duplicate instructions
+ if (!FoundCopy && &MI != DefMI &&
+ MI.isIdenticalTo(*DefMI, MachineInstr::IgnoreDefs)) {
----------------
aengelke wrote:
This seems like it could be a very expensive loop for large blocks.
https://github.com/llvm/llvm-project/pull/163047
_______________________________________________
cfe-commits mailing list
[email protected]
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
