[SelectionDAGBuilder] Support llvm.flt.rounds on targets where i32 is not legal

Add integer expansion for FLT_ROUNDS_ for targets where i32 is not a legal
type.

Patch by Edward Jones, thanks!

Differential Revision: https://reviews.llvm.org/D24459

llvm-svn: 283797

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
index dfed671..d081db5 100644 (file)
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
@@ -1329,6 +1329,7 @@ void DAGTypeLegalizer::ExpandIntegerResult(SDNode *N, unsigned ResNo) {
   case ISD::CTPOP:       ExpandIntRes_CTPOP(N, Lo, Hi); break;
   case ISD::CTTZ_ZERO_UNDEF:
   case ISD::CTTZ:        ExpandIntRes_CTTZ(N, Lo, Hi); break;
+  case ISD::FLT_ROUNDS_: ExpandIntRes_FLT_ROUNDS(N, Lo, Hi); break;
   case ISD::FP_TO_SINT:  ExpandIntRes_FP_TO_SINT(N, Lo, Hi); break;
   case ISD::FP_TO_UINT:  ExpandIntRes_FP_TO_UINT(N, Lo, Hi); break;
   case ISD::LOAD:        ExpandIntRes_LOAD(cast<LoadSDNode>(N), Lo, Hi); break;
@@ -2017,6 +2018,19 @@ void DAGTypeLegalizer::ExpandIntRes_CTTZ(SDNode *N,
   Hi = DAG.getConstant(0, dl, NVT);
 }
 
+void DAGTypeLegalizer::ExpandIntRes_FLT_ROUNDS(SDNode *N, SDValue &Lo,
+                                               SDValue &Hi) {
+  SDLoc dl(N);
+  EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), N->getValueType(0));
+  unsigned NBitWidth = NVT.getSizeInBits();
+
+  EVT ShiftAmtTy = TLI.getShiftAmountTy(NVT, DAG.getDataLayout());
+  Lo = DAG.getNode(ISD::FLT_ROUNDS_, dl, NVT);
+  // The high part is the sign of Lo, as -1 is a valid value for FLT_ROUNDS
+  Hi = DAG.getNode(ISD::SRA, dl, NVT, Lo,
+                   DAG.getConstant(NBitWidth - 1, dl, ShiftAmtTy));
+}
+
 void DAGTypeLegalizer::ExpandIntRes_FP_TO_SINT(SDNode *N, SDValue &Lo,
                                                SDValue &Hi) {
   SDLoc dl(N);

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
index 95e3576..d1022af 100644 (file)
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
@@ -340,6 +340,7 @@ private:
   void ExpandIntRes_SIGN_EXTEND_INREG (SDNode *N, SDValue &Lo, SDValue &Hi);
   void ExpandIntRes_TRUNCATE          (SDNode *N, SDValue &Lo, SDValue &Hi);
   void ExpandIntRes_ZERO_EXTEND       (SDNode *N, SDValue &Lo, SDValue &Hi);
+  void ExpandIntRes_FLT_ROUNDS        (SDNode *N, SDValue &Lo, SDValue &Hi);
   void ExpandIntRes_FP_TO_SINT        (SDNode *N, SDValue &Lo, SDValue &Hi);
   void ExpandIntRes_FP_TO_UINT        (SDNode *N, SDValue &Lo, SDValue &Hi);
 

diff --git a/llvm/test/CodeGen/MSP430/flt_rounds.ll b/llvm/test/CodeGen/MSP430/flt_rounds.ll
new file mode 100644 (file)
index 0000000..fb89363
--- /dev/null
+++ b/llvm/test/CodeGen/MSP430/flt_rounds.ll
@@ -0,0 +1,10 @@
+; RUN: llc -verify-machineinstrs < %s -march=msp430
+
+define i16 @foo() {
+entry:
+  %0 = call i32 @llvm.flt.rounds()
+  %1 = trunc i32 %0 to i16
+  ret i16 %1
+}
+
+declare i32 @llvm.flt.rounds() nounwind