Two improvements:
1. Codegen this comparison:
if (X == 0x8000)
as:
cmplwi cr0, r3, 32768
bne cr0, LBB1_2 ;cond_next
instead of:
lis r2, 0
ori r2, r2, 32768
cmpw cr0, r3, r2
bne cr0, LBB1_2 ;cond_next
2. Codegen this comparison:
if (X == 0x12345678)
as:
xoris r2, r3, 4660
cmplwi cr0, r2, 22136
bne cr0, LBB1_2 ;cond_next
instead of:
lis r2, 4660
ori r2, r2, 22136
cmpw cr0, r3, r2
bne cr0, LBB1_2 ;cond_next
llvm-svn: 30509
diff --git a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
index 4662e53..70b2aa0 100644
--- a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -699,7 +699,33 @@
if (LHS.getValueType() == MVT::i32) {
unsigned Imm;
- if (ISD::isUnsignedIntSetCC(CC)) {
+ if (CC == ISD::SETEQ || CC == ISD::SETNE) {
+ if (isInt32Immediate(RHS, Imm)) {
+ // SETEQ/SETNE comparison with 16-bit immediate, fold it.
+ if (isUInt16(Imm))
+ return SDOperand(CurDAG->getTargetNode(PPC::CMPLWI, MVT::i32, LHS,
+ getI32Imm(Imm & 0xFFFF)), 0);
+ // If this is a 16-bit signed immediate, fold it.
+ if (isInt16(Imm))
+ return SDOperand(CurDAG->getTargetNode(PPC::CMPWI, MVT::i32, LHS,
+ getI32Imm(Imm & 0xFFFF)), 0);
+
+ // For non-equality comparisons, the default code would materialize the
+ // constant, then compare against it, like this:
+ // lis r2, 4660
+ // ori r2, r2, 22136
+ // cmpw cr0, r3, r2
+ // Since we are just comparing for equality, we can emit this instead:
+ // xoris r0,r3,0x1234
+ // cmplwi cr0,r0,0x5678
+ // beq cr0,L6
+ SDOperand Xor(CurDAG->getTargetNode(PPC::XORIS, MVT::i32, LHS,
+ getI32Imm(Imm >> 16)), 0);
+ return SDOperand(CurDAG->getTargetNode(PPC::CMPLWI, MVT::i32, Xor,
+ getI32Imm(Imm & 0xFFFF)), 0);
+ }
+ Opc = PPC::CMPLW;
+ } else if (ISD::isUnsignedIntSetCC(CC)) {
if (isInt32Immediate(RHS, Imm) && isUInt16(Imm))
return SDOperand(CurDAG->getTargetNode(PPC::CMPLWI, MVT::i32, LHS,
getI32Imm(Imm & 0xFFFF)), 0);