allow the offset of a preinc'd load to be the low-part of a global. This

produces this clever code:

_millisecs:
        lis r2, ha16(_Time.1182)
        lwzu r3, lo16(_Time.1182)(r2)
        lwz r2, 4(r2)
        addic r4, r2, 1
        addze r3, r3
        blr

instead of this:

_millisecs:
        lis r2, ha16(_Time.1182)
        la r3, lo16(_Time.1182)(r2)
        lwz r2, lo16(_Time.1182)(r2)
        lwz r3, 4(r3)
        addic r4, r3, 1
        addze r3, r2
        blr

for:

long %millisecs() {
        %tmp = load long* %Time.1182            ; <long> [#uses=1]
        %tmp1 = add long %tmp, 1                ; <long> [#uses=1]
        ret long %tmp1
}

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31673 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
index d3844f469e02bd34a99160122cc85a1041fcd70e..e70eb97871a8f9af93b99854c6a9cfac071f931c 100644 (file)
--- a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -856,7 +856,8 @@ SDNode *PPCDAGToDAGISel::Select(SDOperand Op) {
     }
     
     SDOperand Offset = LD->getOffset();
-    if (isa<ConstantSDNode>(Offset)) {
+    if (isa<ConstantSDNode>(Offset) ||
+        Offset.getOpcode() == ISD::TargetGlobalAddress) {
       SDOperand Chain = LD->getChain();
       SDOperand Base = LD->getBasePtr();
       AddToISelQueue(Chain);