Add isExtractSubreg property.

This patch adds a new property: isExtractSubreg and the related target hooks:
TargetIntrInfo::getExtractSubregInputs and
TargetInstrInfo::getExtractSubregLikeInputs to specify that a target specific
instruction is a (kind of) EXTRACT_SUBREG.

The approach is similar to r215394.

<rdar://problem/12702965>

llvm-svn: 216130

1 files changed, 23 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/TargetInstrInfo.cpp b/llvm/lib/CodeGen/TargetInstrInfo.cpp
index 44fbc4bb631..a177b3d71e0 100644
--- a/llvm/lib/CodeGen/TargetInstrInfo.cpp
+++ b/llvm/lib/CodeGen/TargetInstrInfo.cpp
@@ -877,3 +877,26 @@ bool TargetInstrInfo::getRegSequenceInputs(
   }
   return true;
 }
+
+bool TargetInstrInfo::getExtractSubregInputs(
+    const MachineInstr &MI, unsigned DefIdx,
+    RegSubRegPairAndIdx &InputReg) const {
+  assert((MI.isExtractSubreg() ||
+      MI.isExtractSubregLike()) && "Instruction do not have the proper type");
+
+  if (!MI.isExtractSubreg())
+    return getExtractSubregLikeInputs(MI, DefIdx, InputReg);
+
+  // We are looking at:
+  // Def = EXTRACT_SUBREG v0.sub1, sub0.
+  assert(DefIdx == 0 && "EXTRACT_SUBREG only has one def");
+  const MachineOperand &MOReg = MI.getOperand(1);
+  const MachineOperand &MOSubIdx = MI.getOperand(2);
+  assert(MOSubIdx.isImm() &&
+         "The subindex of the extract_subreg is not an immediate");
+
+  InputReg.Reg = MOReg.getReg();
+  InputReg.SubReg = MOReg.getSubReg();
+  InputReg.SubIdx = (unsigned)MOSubIdx.getImm();
+  return true;
+}