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Two improvements:

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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


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30509 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2006-09-20 04:25:47 +00:00
parent cc96ac3a7d
commit 3836dbd3bd
2 changed files with 27 additions and 22 deletions
Download Patch File Download Diff File Expand all files Collapse all files

28
lib/Target/PowerPC/PPCISelDAGToDAG.cpp
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@@ -699,7 +699,33 @@ SDOperand PPCDAGToDAGISel::SelectCC(SDOperand LHS, SDOperand RHS,
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);