Compile test/CodeGen/PowerPC/LargeAbsoluteAddr.ll to:

_test:
        lis r2, 743
        li r3, 0
        stw r3, 32751(r2)
        blr

instead of:

_test:
        li r2, 0
        stw r2, 32751(48693248)
        blr

Implement support for ppc64 as well, allowing it to produce better code.

llvm-svn: 34371

1 files changed, 9 insertions, 5 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index 88815a7c5ad..56f5d11f955 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -743,14 +743,18 @@ bool PPCTargetLowering::SelectAddressRegImm(SDOperand N, SDOperand &Disp,
       Base = DAG.getRegister(PPC::R0, CN->getValueType(0));
       return true;
     }
-    
-    // FIXME: Handle small sext constant offsets in PPC64 mode also!
-    if (CN->getValueType(0) == MVT::i32) {
+
+    // Handle 32-bit sext immediates with LIS + addr mode.
+    if (CN->getValueType(0) == MVT::i32 ||
+        (int64_t)CN->getValue() == (int)CN->getValue()) {
       int Addr = (int)CN->getValue();
       
       // Otherwise, break this down into an LIS + disp.
-      Disp =  DAG.getTargetConstant((short)Addr, MVT::i32);
-      Base = DAG.getConstant(Addr - (signed short)Addr, MVT::i32);
+      Disp = DAG.getTargetConstant((short)Addr, MVT::i32);
+      
+      Base = DAG.getTargetConstant((Addr - (signed short)Addr) >> 16, MVT::i32);
+      unsigned Opc = CN->getValueType(0) == MVT::i32 ? PPC::LIS : PPC::LIS8;
+      Base = SDOperand(DAG.getTargetNode(Opc, CN->getValueType(0), Base), 0);
       return true;
     }
   }