Adjust isConstantSplat to allow for big-endian targets.

PPC is such a target; make it work.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@87060 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/CodeGen/SelectionDAGNodes.h b/include/llvm/CodeGen/SelectionDAGNodes.h
index f9608514c51383900eb306f63f078f83a31129b1..d4d40b13e45a311bbf50dcb4e5ac12be5b203c8a 100644 (file)
--- a/include/llvm/CodeGen/SelectionDAGNodes.h
+++ b/include/llvm/CodeGen/SelectionDAGNodes.h
@@ -1953,10 +1953,10 @@ public:
   /// that value are zero, and the corresponding bits in the SplatUndef mask
   /// are set.  The SplatBitSize value is set to the splat element size in
   /// bits.  HasAnyUndefs is set to true if any bits in the vector are
-  /// undefined.
+  /// undefined.  isBigEndian describes the endianness of the target.
   bool isConstantSplat(APInt &SplatValue, APInt &SplatUndef,
                        unsigned &SplatBitSize, bool &HasAnyUndefs,
-                       unsigned MinSplatBits = 0);
+                       unsigned MinSplatBits = 0, bool isBigEndian = false);
 
   static inline bool classof(const BuildVectorSDNode *) { return true; }
   static inline bool classof(const SDNode *N) {

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index d9c273d266a366bfb3b7ea3361f830c25dc0bf9e..4530ffc4a2d0d5bdb88f5ae1a883be6b0033874b 100644 (file)
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -5916,7 +5916,8 @@ bool BuildVectorSDNode::isConstantSplat(APInt &SplatValue,
                                         APInt &SplatUndef,
                                         unsigned &SplatBitSize,
                                         bool &HasAnyUndefs,
-                                        unsigned MinSplatBits) {
+                                        unsigned MinSplatBits,
+                                        bool isBigEndian) {
   EVT VT = getValueType(0);
   assert(VT.isVector() && "Expected a vector type");
   unsigned sz = VT.getSizeInBits();
@@ -5933,12 +5934,14 @@ bool BuildVectorSDNode::isConstantSplat(APInt &SplatValue,
   unsigned int nOps = getNumOperands();
   assert(nOps > 0 && "isConstantSplat has 0-size build vector");
   unsigned EltBitSize = VT.getVectorElementType().getSizeInBits();
-  for (unsigned i = 0; i < nOps; ++i) {
+
+  for (unsigned j = 0; j < nOps; ++j) {
+    unsigned i = isBigEndian ? nOps-1-j : j;
     SDValue OpVal = getOperand(i);
-    unsigned BitPos = i * EltBitSize;
+    unsigned BitPos = j * EltBitSize;
 
     if (OpVal.getOpcode() == ISD::UNDEF)
-      SplatUndef |= APInt::getBitsSet(sz, BitPos, BitPos +EltBitSize);
+      SplatUndef |= APInt::getBitsSet(sz, BitPos, BitPos + EltBitSize);
     else if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(OpVal))
       SplatValue |= (APInt(CN->getAPIntValue()).zextOrTrunc(EltBitSize).
                      zextOrTrunc(sz) << BitPos);

diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index 33462467163da7b8c9bb2629b6c94223a4226c74..099fcb5e8a92e9d73039415ec6b0beef69557637 100644 (file)
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -637,7 +637,7 @@ bool PPC::isAllNegativeZeroVector(SDNode *N) {
   unsigned BitSize;
   bool HasAnyUndefs;
   
-  if (BV->isConstantSplat(APVal, APUndef, BitSize, HasAnyUndefs, 32))
+  if (BV->isConstantSplat(APVal, APUndef, BitSize, HasAnyUndefs, 32, true))
     if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N->getOperand(0)))
       return CFP->getValueAPF().isNegZero();
 
@@ -3672,7 +3672,7 @@ SDValue PPCTargetLowering::LowerBUILD_VECTOR(SDValue Op, SelectionDAG &DAG) {
   unsigned SplatBitSize;
   bool HasAnyUndefs;
   if (! BVN->isConstantSplat(APSplatBits, APSplatUndef, SplatBitSize,
-                             HasAnyUndefs) || SplatBitSize > 32)
+                             HasAnyUndefs, 0, true) || SplatBitSize > 32)
     return SDValue();
 
   unsigned SplatBits = APSplatBits.getZExtValue();

diff --git a/test/CodeGen/PowerPC/vec_splat_constant.ll b/test/CodeGen/PowerPC/vec_splat_constant.ll
new file mode 100644 (file)
index 0000000..b227794
--- /dev/null
+++ b/test/CodeGen/PowerPC/vec_splat_constant.ll
@@ -0,0 +1,24 @@
+; RUN: llc < %s -march=ppc32 -mtriple=powerpc-apple-darwin -mcpu=g5 | FileCheck %s
+; Formerly incorrectly inserted vsldoi (endian confusion)
+
+@baz = common global <16 x i8> zeroinitializer    ; <<16 x i8>*> [#uses=1]
+
+define void @foo(<16 x i8> %x) nounwind ssp {
+entry:
+; CHECK: _foo:
+; CHECK-NOT: vsldoi
+  %x_addr = alloca <16 x i8>                      ; <<16 x i8>*> [#uses=2]
+  %temp = alloca <16 x i8>                        ; <<16 x i8>*> [#uses=2]
+  %"alloca point" = bitcast i32 0 to i32          ; <i32> [#uses=0]
+  store <16 x i8> %x, <16 x i8>* %x_addr
+  store <16 x i8> <i8 0, i8 0, i8 0, i8 14, i8 0, i8 0, i8 0, i8 14, i8 0, i8 0, i8 0, i8 14, i8 0, i8 0, i8 0, i8 14>, <16 x i8>* %temp, align 16
+  %0 = load <16 x i8>* %x_addr, align 16          ; <<16 x i8>> [#uses=1]
+  %1 = load <16 x i8>* %temp, align 16            ; <<16 x i8>> [#uses=1]
+  %tmp = add <16 x i8> %0, %1                     ; <<16 x i8>> [#uses=1]
+  store <16 x i8> %tmp, <16 x i8>* @baz, align 16
+  br label %return
+
+return:                                           ; preds = %entry
+  ret void
+; CHECK: blr
+}