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[XCore] Make use of the target independent global address offset folding.

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This let us to remove some custom code that matched constant offsets
from globals at instruction selection time as a special addressing mode.
No intended functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181126 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Richard Osborne
2013-05-04 17:24:33 +00:00
parent 40827bc716
commit 6ffbf6ea8f
6 changed files with 41 additions and 98 deletions
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lib/Target/XCore/XCoreISelLowering.cpp
+29 -13
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@@ -36,6 +36,8 @@
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
using namespace llvm;
const char *XCoreTargetLowering::
@@ -241,9 +243,20 @@ getGlobalAddressWrapper(SDValue GA, const GlobalValue *GV,
SDValue XCoreTargetLowering::
LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) const
{
const GlobalValue *GV = cast<GlobalAddressSDNode>(Op)->getGlobal();
SDValue GA = DAG.getTargetGlobalAddress(GV, Op.getDebugLoc(), MVT::i32);
return getGlobalAddressWrapper(GA, GV, DAG);
DebugLoc DL = Op.getDebugLoc();
const GlobalAddressSDNode *GN = cast<GlobalAddressSDNode>(Op);
const GlobalValue *GV = GN->getGlobal();
int64_t Offset = GN->getOffset();
// We can only fold positive offsets that are a multiple of the word size.
int64_t FoldedOffset = std::max(Offset & ~3, 0LL);
SDValue GA = DAG.getTargetGlobalAddress(GV, DL, MVT::i32, FoldedOffset);
GA = getGlobalAddressWrapper(GA, GV, DAG);
// Handle the rest of the offset.
if (Offset != FoldedOffset) {
SDValue Remaining = DAG.getConstant(Offset - FoldedOffset, MVT::i32);
GA = DAG.getNode(ISD::ADD, DL, MVT::i32, GA, Remaining);
}
return GA;
}
static inline SDValue BuildGetId(SelectionDAG &DAG, DebugLoc dl) {
@@ -319,10 +332,19 @@ lowerLoadWordFromAlignedBasePlusOffset(DebugLoc DL, SDValue Chain, SDValue Base,
// Lower to pair of consecutive word aligned loads plus some bit shifting.
int32_t HighOffset = RoundUpToAlignment(Offset, 4);
int32_t LowOffset = HighOffset - 4;
SDValue LowAddr = DAG.getNode(ISD::ADD, DL, MVT::i32, Base,
DAG.getConstant(LowOffset, MVT::i32));
SDValue HighAddr = DAG.getNode(ISD::ADD, DL, MVT::i32, Base,
DAG.getConstant(HighOffset, MVT::i32));
SDValue LowAddr, HighAddr;
if (GlobalAddressSDNode *GASD =
dyn_cast<GlobalAddressSDNode>(Base.getNode())) {
LowAddr = DAG.getGlobalAddress(GASD->getGlobal(), DL, Base.getValueType(),
LowOffset);
HighAddr = DAG.getGlobalAddress(GASD->getGlobal(), DL, Base.getValueType(),
HighOffset);
} else {
LowAddr = DAG.getNode(ISD::ADD, DL, MVT::i32, Base,
DAG.getConstant(LowOffset, MVT::i32));
HighAddr = DAG.getNode(ISD::ADD, DL, MVT::i32, Base,
DAG.getConstant(HighOffset, MVT::i32));
}
SDValue LowShift = DAG.getConstant((Offset - LowOffset) * 8, MVT::i32);
SDValue HighShift = DAG.getConstant((HighOffset - Offset) * 8, MVT::i32);
@@ -1553,12 +1575,6 @@ XCoreTargetLowering::isLegalAddressingMode(const AddrMode &AM,
}
}
bool XCoreTargetLowering::
isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const {
// The XCore target isn't yet aware of offsets.
return false;
}
//===----------------------------------------------------------------------===//
// XCore Inline Assembly Support
//===----------------------------------------------------------------------===//