[SelectionDAG] Support result type promotion for FLT_ROUNDS_

For targets where i32 is not a legal type (e.g. 64-bit RISC-V), 
LegalizeIntegerTypes must promote the result of ISD::FLT_ROUNDS_.

Differential Revision: https://reviews.llvm.org/D53820

llvm-svn: 347986

3 files changed, 31 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
index 2a89af94902..265f67b7659 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
@@ -118,6 +118,8 @@ void DAGTypeLegalizer::PromoteIntegerResult(SDNode *N, unsigned ResNo) {
 
   case ISD::FP_TO_FP16:  Res = PromoteIntRes_FP_TO_FP16(N); break;
 
+  case ISD::FLT_ROUNDS_: Res = PromoteIntRes_FLT_ROUNDS(N); break;
+
   case ISD::AND:
   case ISD::OR:
   case ISD::XOR:
@@ -475,6 +477,13 @@ SDValue DAGTypeLegalizer::PromoteIntRes_FP_TO_FP16(SDNode *N) {
   return DAG.getNode(N->getOpcode(), dl, NVT, N->getOperand(0));
 }
 
+SDValue DAGTypeLegalizer::PromoteIntRes_FLT_ROUNDS(SDNode *N) {
+  EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), N->getValueType(0));
+  SDLoc dl(N);
+
+  return DAG.getNode(N->getOpcode(), dl, NVT);
+}
+
 SDValue DAGTypeLegalizer::PromoteIntRes_INT_EXTEND(SDNode *N) {
   EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), N->getValueType(0));
   SDLoc dl(N);
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
index e00743436c6..38a23729a1d 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
@@ -345,6 +345,7 @@ private:
   SDValue PromoteIntRes_VAARG(SDNode *N);
   SDValue PromoteIntRes_XMULO(SDNode *N, unsigned ResNo);
   SDValue PromoteIntRes_ADDSUBSAT(SDNode *N);
+  SDValue PromoteIntRes_FLT_ROUNDS(SDNode *N);
 
   // Integer Operand Promotion.
   bool PromoteIntegerOperand(SDNode *N, unsigned OpNo);
diff --git a/llvm/test/CodeGen/RISCV/flt-rounds.ll b/llvm/test/CodeGen/RISCV/flt-rounds.ll
new file mode 100644
index 00000000000..cb6d166de4f
--- /dev/null
+++ b/llvm/test/CodeGen/RISCV/flt-rounds.ll
@@ -0,0 +1,21 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=riscv32 -verify-machineinstrs < %s \
+; RUN:   | FileCheck -check-prefix=RV32I %s
+; RUN: llc -mtriple=riscv64 -verify-machineinstrs < %s \
+; RUN:   | FileCheck -check-prefix=RV64I %s
+
+declare i32 @llvm.flt.rounds()
+
+define i32 @test_flt_rounds() nounwind {
+; RV32I-LABEL: test_flt_rounds:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    addi a0, zero, 1
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: test_flt_rounds:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    addi a0, zero, 1
+; RV64I-NEXT:    ret
+  %1 = call i32 @llvm.flt.rounds()
+  ret i32 %1
+}