diff options
| -rw-r--r-- | lib/Target/PowerPC/PPCISelDAGToDAG.cpp | 28 | ||||
| -rw-r--r-- | lib/Target/PowerPC/README.txt | 21 |
2 files changed, 27 insertions, 22 deletions
diff --git a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp index 4662e531a9..70b2aa0577 100644 --- a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp +++ b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp @@ -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); diff --git a/lib/Target/PowerPC/README.txt b/lib/Target/PowerPC/README.txt index cfc7eb38b2..4f7f2cff10 100644 --- a/lib/Target/PowerPC/README.txt +++ b/lib/Target/PowerPC/README.txt @@ -50,27 +50,6 @@ we don't have to always run the branch selector for small functions. ===-------------------------------------------------------------------------=== -* Codegen this: - - void test2(int X) { - if (X == 0x12345678) bar(); - } - - as: - - xoris r0,r3,0x1234 - cmplwi cr0,r0,0x5678 - beq cr0,L6 - - not: - - lis r2, 4660 - ori r2, r2, 22136 - cmpw cr0, r3, r2 - bne .LBB_test2_2 - -===-------------------------------------------------------------------------=== - Lump the constant pool for each function into ONE pic object, and reference pieces of it as offsets from the start. For functions like this (contrived to have lots of constants obviously): |