[llvm] r216277 - R600/SI: Wrap local memory pointer in AssertZExt on SI

[Tom Stellard]

Author: tstellar
Date: Fri Aug 22 13:49:31 2014
New Revision: 216277

URL: http://llvm.org/viewvc/llvm-project?rev=216277&view=rev
Log:
R600/SI: Wrap local memory pointer in AssertZExt on SI

These pointers are really just offsets and they will always be
less than 16-bits.  Using AssertZExt allows us to use computeKnownBits
to prove that these values are positive.  We will use this information
in a later commit.

Modified:
    llvm/trunk/lib/Target/R600/SIISelLowering.cpp

Modified: llvm/trunk/lib/Target/R600/SIISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/R600/SIISelLowering.cpp?rev=216277&r1=216276&r2=216277&view=diff
==============================================================================
--- llvm/trunk/lib/Target/R600/SIISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/R600/SIISelLowering.cpp Fri Aug 22 13:49:31 2014
@@ -504,6 +504,18 @@ SDValue SITargetLowering::LowerFormalArg
       SDValue Arg = LowerParameter(DAG, VT, MemVT,  DL, DAG.getRoot(),
                                    36 + VA.getLocMemOffset(),
                                    Ins[i].Flags.isSExt());
+
+      const PointerType *ParamTy =
+          dyn_cast<PointerType>(FType->getParamType(Ins[i].OrigArgIndex));
+      if (Subtarget->getGeneration() == AMDGPUSubtarget::SOUTHERN_ISLANDS &&
+          ParamTy && ParamTy->getAddressSpace() == AMDGPUAS::LOCAL_ADDRESS) {
+        // On SI local pointers are just offsets into LDS, so they are always
+        // less than 16-bits.  On CI and newer they could potentially be
+        // real pointers, so we can't guarantee their size.
+        Arg = DAG.getNode(ISD::AssertZext, DL, Arg.getValueType(), Arg,
+                          DAG.getValueType(MVT::i16));
+      }
+
       InVals.push_back(Arg);
       continue;
     }