reapply the patches reverted in r149470 that reenable ConstantDataArray,
but with a critical fix to the SelectionDAG code that optimizes copies
from strings into immediate stores: the previous code was stopping reading
string data at the first nul. Address this by adding a new argument to
llvm::getConstantStringInfo, preserving the behavior before the patch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149800 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 18de13d..0f20978 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -3298,8 +3298,7 @@
/// used when a memcpy is turned into a memset when the source is a constant
/// string ptr.
static SDValue getMemsetStringVal(EVT VT, DebugLoc dl, SelectionDAG &DAG,
- const TargetLowering &TLI,
- std::string &Str, unsigned Offset) {
+ const TargetLowering &TLI, StringRef Str) {
// Handle vector with all elements zero.
if (Str.empty()) {
if (VT.isInteger())
@@ -3317,15 +3316,18 @@
}
assert(!VT.isVector() && "Can't handle vector type here!");
- unsigned NumBits = VT.getSizeInBits();
- unsigned MSB = NumBits / 8;
+ unsigned NumVTBytes = VT.getSizeInBits() / 8;
+ unsigned NumBytes = std::min(NumVTBytes, unsigned(Str.size()));
+
uint64_t Val = 0;
- if (TLI.isLittleEndian())
- Offset = Offset + MSB - 1;
- for (unsigned i = 0; i != MSB; ++i) {
- Val = (Val << 8) | (unsigned char)Str[Offset];
- Offset += TLI.isLittleEndian() ? -1 : 1;
+ if (TLI.isLittleEndian()) {
+ for (unsigned i = 0; i != NumBytes; ++i)
+ Val |= (uint64_t)(unsigned char)Str[i] << i*8;
+ } else {
+ for (unsigned i = 0; i != NumBytes; ++i)
+ Val |= (uint64_t)(unsigned char)Str[i] << (NumVTBytes-i-1)*8;
}
+
return DAG.getConstant(Val, VT);
}
@@ -3340,7 +3342,7 @@
/// isMemSrcFromString - Returns true if memcpy source is a string constant.
///
-static bool isMemSrcFromString(SDValue Src, std::string &Str) {
+static bool isMemSrcFromString(SDValue Src, StringRef &Str) {
unsigned SrcDelta = 0;
GlobalAddressSDNode *G = NULL;
if (Src.getOpcode() == ISD::GlobalAddress)
@@ -3354,11 +3356,7 @@
if (!G)
return false;
- const GlobalVariable *GV = dyn_cast<GlobalVariable>(G->getGlobal());
- if (GV && GetConstantStringInfo(GV, Str, SrcDelta, false))
- return true;
-
- return false;
+ return getConstantStringInfo(G->getGlobal(), Str, SrcDelta, false);
}
/// FindOptimalMemOpLowering - Determines the optimial series memory ops
@@ -3461,7 +3459,7 @@
unsigned SrcAlign = DAG.InferPtrAlignment(Src);
if (Align > SrcAlign)
SrcAlign = Align;
- std::string Str;
+ StringRef Str;
bool CopyFromStr = isMemSrcFromString(Src, Str);
bool isZeroStr = CopyFromStr && Str.empty();
unsigned Limit = AlwaysInline ? ~0U : TLI.getMaxStoresPerMemcpy(OptSize);
@@ -3498,7 +3496,7 @@
// We only handle zero vectors here.
// FIXME: Handle other cases where store of vector immediate is done in
// a single instruction.
- Value = getMemsetStringVal(VT, dl, DAG, TLI, Str, SrcOff);
+ Value = getMemsetStringVal(VT, dl, DAG, TLI, Str.substr(SrcOff));
Store = DAG.getStore(Chain, dl, Value,
getMemBasePlusOffset(Dst, DstOff, DAG),
DstPtrInfo.getWithOffset(DstOff), isVol,