[PATCH] D98791: [PowerPC][NFC] Do not enter prefix selection if it cannot do better.

[Stefan Pintilie via Phabricator via llvm-commits]

stefanp updated this revision to Diff 332278.
stefanp added a comment.

Updated comment.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D98791/new/

https://reviews.llvm.org/D98791

Files:
  llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp


Index: llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
===================================================================
--- llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -1167,7 +1167,10 @@
   const PPCSubtarget &Subtarget =
       CurDAG->getMachineFunction().getSubtarget<PPCSubtarget>();
 
-  if (Subtarget.hasPrefixInstrs()) {
+  // If we have prefixed instructions and there is a chance we can
+  // materialize the constant with fewer prefixed instructions than
+  // non-prefixed, try that.
+  if (Subtarget.hasPrefixInstrs() && InstCntDirect != 1) {
     unsigned InstCntDirectP = 0;
     SDNode *ResultP = selectI64ImmDirectPrefix(CurDAG, dl, Imm, InstCntDirectP);
     // Use the prefix case in either of two cases:


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