[PATCH] D157287: [LegalizeTypes][RISCV] Correct FP_TO_{S,U}INT expansion when bf16 isn't a legal type

[Alex Bradbury via Phabricator via llvm-commits]

asb updated this revision to Diff 548189.
asb added a comment.

Apologies for the noise, the previous versions had a bug in that they were checking the type of Op.getValueType after `Op = GetSoftPromotedHalf(Op)`. The patch now correctly gets the old FP VT before doing that call. This bug was caught by existing tests (I just hadn't seen that half-convert.ll failed) so no further test changes needed.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D157287/new/

https://reviews.llvm.org/D157287

Files:
  llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
  llvm/test/CodeGen/RISCV/bfloat-convert.ll


Index: llvm/test/CodeGen/RISCV/bfloat-convert.ll
===================================================================
--- llvm/test/CodeGen/RISCV/bfloat-convert.ll
+++ llvm/test/CodeGen/RISCV/bfloat-convert.ll
@@ -431,9 +431,6 @@
 }
 declare i32 @llvm.fptoui.sat.i32.bf16(bfloat)
 
-; TODO: An f16 libcall is incorrectly produced for RV32ID in the following
-; test.
-
 define i64 @fcvt_l_bf16(bfloat %a) nounwind {
 ; CHECK32ZFBFMIN-LABEL: fcvt_l_bf16:
 ; CHECK32ZFBFMIN:       # %bb.0:
@@ -449,7 +446,9 @@
 ; RV32ID:       # %bb.0:
 ; RV32ID-NEXT:    addi sp, sp, -16
 ; RV32ID-NEXT:    sw ra, 12(sp) # 4-byte Folded Spill
-; RV32ID-NEXT:    call __extendhfsf2 at plt
+; RV32ID-NEXT:    fmv.x.w a0, fa0
+; RV32ID-NEXT:    slli a0, a0, 16
+; RV32ID-NEXT:    fmv.w.x fa0, a0
 ; RV32ID-NEXT:    call __fixsfdi at plt
 ; RV32ID-NEXT:    lw ra, 12(sp) # 4-byte Folded Reload
 ; RV32ID-NEXT:    addi sp, sp, 16
@@ -623,9 +622,6 @@
 }
 declare i64 @llvm.fptosi.sat.i64.bf16(bfloat)
 
-; TODO: An f16 libcall is incorrectly produced for RV32ID in the following
-; test.
-
 define i64 @fcvt_lu_bf16(bfloat %a) nounwind {
 ; CHECK32ZFBFMIN-LABEL: fcvt_lu_bf16:
 ; CHECK32ZFBFMIN:       # %bb.0:
@@ -641,7 +637,9 @@
 ; RV32ID:       # %bb.0:
 ; RV32ID-NEXT:    addi sp, sp, -16
 ; RV32ID-NEXT:    sw ra, 12(sp) # 4-byte Folded Spill
-; RV32ID-NEXT:    call __extendhfsf2 at plt
+; RV32ID-NEXT:    fmv.x.w a0, fa0
+; RV32ID-NEXT:    slli a0, a0, 16
+; RV32ID-NEXT:    fmv.w.x fa0, a0
 ; RV32ID-NEXT:    call __fixunssfdi at plt
 ; RV32ID-NEXT:    lw ra, 12(sp) # 4-byte Folded Reload
 ; RV32ID-NEXT:    addi sp, sp, 16
Index: llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
+++ llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
@@ -3614,9 +3614,11 @@
     Op = GetPromotedFloat(Op);
 
   if (getTypeAction(Op.getValueType()) == TargetLowering::TypeSoftPromoteHalf) {
-    EVT NFPVT = TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType());
+    EVT OFPVT = Op.getValueType();
+    EVT NFPVT = TLI.getTypeToTransformTo(*DAG.getContext(), OFPVT);
     Op = GetSoftPromotedHalf(Op);
-    Op = DAG.getNode(ISD::FP16_TO_FP, dl, NFPVT, Op);
+    Op = DAG.getNode(OFPVT == MVT::f16 ? ISD::FP16_TO_FP : ISD::BF16_TO_FP, dl,
+                     NFPVT, Op);
     Op = DAG.getNode(ISD::FP_TO_SINT, dl, VT, Op);
     SplitInteger(Op, Lo, Hi);
     return;
@@ -3651,9 +3653,11 @@
     Op = GetPromotedFloat(Op);
 
   if (getTypeAction(Op.getValueType()) == TargetLowering::TypeSoftPromoteHalf) {
-    EVT NFPVT = TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType());
+    EVT OFPVT = Op.getValueType();
+    EVT NFPVT = TLI.getTypeToTransformTo(*DAG.getContext(), OFPVT);
     Op = GetSoftPromotedHalf(Op);
-    Op = DAG.getNode(ISD::FP16_TO_FP, dl, NFPVT, Op);
+    Op = DAG.getNode(OFPVT == MVT::f16 ? ISD::FP16_TO_FP : ISD::BF16_TO_FP, dl,
+                     NFPVT, Op);
     Op = DAG.getNode(ISD::FP_TO_UINT, dl, VT, Op);
     SplitInteger(Op, Lo, Hi);
     return;


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