[ARM][SDAG] Half promote llvm.lrint nodes.

As shown in #137101, fp16 lrint are not handled correctly on Arm. This adds
soft-half promotion for them, reusing the function that promotes a value with
operands (and can handle strict fp once that is added).

Author: davemgreen

llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp

@@ -3740,7 +3740,10 @@ bool DAGTypeLegalizer::SoftPromoteHalfOperand(SDNode *N, unsigned OpNo) {
   case ISD::STRICT_FP_TO_SINT:
   case ISD::STRICT_FP_TO_UINT:
   case ISD::FP_TO_SINT:
-  case ISD::FP_TO_UINT: Res = SoftPromoteHalfOp_FP_TO_XINT(N); break;
+  case ISD::FP_TO_UINT:
+  case ISD::LRINT:
+    Res = SoftPromoteHalfOp_Op0WithStrict(N);
+    break;
   case ISD::FP_TO_SINT_SAT:
   case ISD::FP_TO_UINT_SAT:
                         Res = SoftPromoteHalfOp_FP_TO_XINT_SAT(N); break;
@@ -3819,7 +3822,7 @@ SDValue DAGTypeLegalizer::SoftPromoteHalfOp_FP_EXTEND(SDNode *N) {
   return DAG.getNode(GetPromotionOpcode(SVT, RVT), SDLoc(N), RVT, Op);
 }
 
-SDValue DAGTypeLegalizer::SoftPromoteHalfOp_FP_TO_XINT(SDNode *N) {
+SDValue DAGTypeLegalizer::SoftPromoteHalfOp_Op0WithStrict(SDNode *N) {
   EVT RVT = N->getValueType(0);
   bool IsStrict = N->isStrictFPOpcode();
   SDValue Op = N->getOperand(IsStrict ? 1 : 0);

llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h

@@ -843,7 +843,7 @@ class LLVM_LIBRARY_VISIBILITY DAGTypeLegalizer {
   SDValue SoftPromoteHalfOp_FAKE_USE(SDNode *N, unsigned OpNo);
   SDValue SoftPromoteHalfOp_FCOPYSIGN(SDNode *N, unsigned OpNo);
   SDValue SoftPromoteHalfOp_FP_EXTEND(SDNode *N);
-  SDValue SoftPromoteHalfOp_FP_TO_XINT(SDNode *N);
+  SDValue SoftPromoteHalfOp_Op0WithStrict(SDNode *N);
   SDValue SoftPromoteHalfOp_FP_TO_XINT_SAT(SDNode *N);
   SDValue SoftPromoteHalfOp_SETCC(SDNode *N);
   SDValue SoftPromoteHalfOp_SELECT_CC(SDNode *N, unsigned OpNo);

llvm/lib/Target/ARM/ARMISelLowering.cpp

@@ -1353,6 +1353,7 @@ ARMTargetLowering::ARMTargetLowering(const TargetMachine &TM_,
     setOperationAction(ISD::FLOG, MVT::f16, Promote);
     setOperationAction(ISD::FLOG10, MVT::f16, Promote);
     setOperationAction(ISD::FLOG2, MVT::f16, Promote);
+    setOperationAction(ISD::LRINT, MVT::f16, Expand);
 
     setOperationAction(ISD::FROUND, MVT::f16, Legal);
     setOperationAction(ISD::FROUNDEVEN, MVT::f16, Legal);

llvm/test/CodeGen/ARM/lrint-conv.ll

@@ -3,12 +3,35 @@
 ; RUN: llc < %s -mtriple=armv7-none-eabihf -mattr=+vfp2 -float-abi=hard | FileCheck %s --check-prefixes=CHECK,CHECK-NOFP16
 ; RUN: llc < %s -mtriple=armv7-none-eabihf -mattr=+vfp2,+fullfp16 -float-abi=hard | FileCheck %s --check-prefixes=CHECK,CHECK-FP16
 
-; FIXME: crash
-; define i32 @testmswh_builtin(half %x) {
-; entry:
-;   %0 = tail call i32 @llvm.lrint.i32.f16(half %x)
-;   ret i32 %0
-; }
+define i32 @testmswh_builtin(half %x) {
+; CHECK-SOFT-LABEL: testmswh_builtin:
+; CHECK-SOFT:       @ %bb.0: @ %entry
+; CHECK-SOFT-NEXT:    .save {r11, lr}
+; CHECK-SOFT-NEXT:    push {r11, lr}
+; CHECK-SOFT-NEXT:    bl __aeabi_h2f
+; CHECK-SOFT-NEXT:    pop {r11, lr}
+; CHECK-SOFT-NEXT:    b lrintf
+;
+; CHECK-NOFP16-LABEL: testmswh_builtin:
+; CHECK-NOFP16:       @ %bb.0: @ %entry
+; CHECK-NOFP16-NEXT:    .save {r11, lr}
+; CHECK-NOFP16-NEXT:    push {r11, lr}
+; CHECK-NOFP16-NEXT:    vmov r0, s0
+; CHECK-NOFP16-NEXT:    bl __aeabi_h2f
+; CHECK-NOFP16-NEXT:    vmov s0, r0
+; CHECK-NOFP16-NEXT:    pop {r11, lr}
+; CHECK-NOFP16-NEXT:    b lrintf
+;
+; CHECK-FP16-LABEL: testmswh_builtin:
+; CHECK-FP16:       @ %bb.0: @ %entry
+; CHECK-FP16-NEXT:    vrintx.f16 s0, s0
+; CHECK-FP16-NEXT:    vcvt.s32.f16 s0, s0
+; CHECK-FP16-NEXT:    vmov r0, s0
+; CHECK-FP16-NEXT:    bx lr
+entry:
+  %0 = tail call i32 @llvm.lrint.i32.f16(half %x)
+  ret i32 %0
+}
 
 define i32 @testmsws_builtin(float %x) {
 ; CHECK-LABEL: testmsws_builtin:
@@ -39,8 +62,3 @@ entry:
   %0 = tail call i32 @llvm.lrint.i32.f128(fp128 %x)
   ret i32 %0
 }
-
-;; NOTE: These prefixes are unused and the list is autogenerated. Do not add tests below this line:
-; CHECK-FP16: {{.*}}
-; CHECK-NOFP16: {{.*}}
-; CHECK-SOFT: {{.*}}