From 2a2a323488a31fbdb3524f7f288b8e5c3fc3b7c3 Mon Sep 17 00:00:00 2001 From: Richard Sandiford Date: Tue, 3 Dec 2013 11:05:09 +0000 Subject: Merging r196267: ------------------------------------------------------------------------ r196267 | rsandifo | 2013-12-03 11:01:54 +0000 (Tue, 03 Dec 2013) | 12 lines [SystemZ] Fix choice of known-zero mask in insertion optimization The backend converts 64-bit ORs into subreg moves if the upper 32 bits of one operand and the low 32 bits of the other are known to be zero. It then tries to peel away redundant ANDs from the upper 32 bits. Since AND masks are canonicalized to exclude known-zero bits, the test ORs the mask and the known-zero bits together before checking for redundancy. The problem was that it was using the wrong node when checking for known-zero bits, so could drop ANDs that were still needed. ------------------------------------------------------------------------ git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_34@196268 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/SystemZ/SystemZISelLowering.cpp | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'lib/Target') diff --git a/lib/Target/SystemZ/SystemZISelLowering.cpp b/lib/Target/SystemZ/SystemZISelLowering.cpp index 4a5fb42..f6e1853 100644 --- a/lib/Target/SystemZ/SystemZISelLowering.cpp +++ b/lib/Target/SystemZ/SystemZISelLowering.cpp @@ -1933,10 +1933,10 @@ SDValue SystemZTargetLowering::lowerOR(SDValue Op, SelectionDAG &DAG) const { // high 32 bits and just masks out low bits. We can skip it if so. if (HighOp.getOpcode() == ISD::AND && HighOp.getOperand(1).getOpcode() == ISD::Constant) { - ConstantSDNode *MaskNode = cast(HighOp.getOperand(1)); - uint64_t Mask = MaskNode->getZExtValue() | Masks[High]; - if ((Mask >> 32) == 0xffffffff) - HighOp = HighOp.getOperand(0); + SDValue HighOp0 = HighOp.getOperand(0); + uint64_t Mask = cast(HighOp.getOperand(1))->getZExtValue(); + if (DAG.MaskedValueIsZero(HighOp0, APInt(64, ~(Mask | 0xffffffff)))) + HighOp = HighOp0; } // Take advantage of the fact that all GR32 operations only change the -- cgit v1.1