Like the comment says, prefer to use the implicit add done by [r+r] addressing
modes than emitting an explicit add and using a base of r0. This implements
Regression/CodeGen/PowerPC/mem-rr-addr-mode.ll
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@27068 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
index 459ddfa..2941b34 100644
--- a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -616,11 +616,21 @@
// Check to see if we can easily represent this as an [r+r] address. This
// will fail if it thinks that the address is more profitably represented as
// reg+imm, e.g. where imm = 0.
- if (!SelectAddrIdx(N, Base, Index)) {
- // Nope, do it the hard way.
- Base = CurDAG->getRegister(PPC::R0, MVT::i32);
- Index = N;
+ if (SelectAddrIdx(N, Base, Index))
+ return true;
+
+ // If the operand is an addition, always emit this as [r+r], since this is
+ // better (for code size, and execution, as the memop does the add for free)
+ // than emitting an explicit add.
+ if (N.getOpcode() == ISD::ADD) {
+ Base = N.getOperand(0);
+ Index = N.getOperand(1);
+ return true;
}
+
+ // Otherwise, do it the hard way, using R0 as the base register.
+ Base = CurDAG->getRegister(PPC::R0, MVT::i32);
+ Index = N;
return true;
}