[llvm-branch-commits] [llvm] DAG: Gracefully diagnose missing lrint/lround float-operand libcalls (PR #215064)

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llvmorg-github-actions[bot] wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-x86

Author: Matt Arsenault (arsenm)

<details>
<summary>Changes</summary>

Co-authored-by: Claude (Claude-Opus-4.8) <noreply@<!-- -->anthropic.com>

---
Full diff: https://github.com/llvm/llvm-project/pull/215064.diff


3 Files Affected:

- (modified) llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp (+32-36) 
- (modified) llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h (+1) 
- (modified) llvm/test/CodeGen/X86/xrint-no-libcall-error.ll (+12) 


``````````diff
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
index d0a29b5365daa..9d28b67ea2869 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
@@ -2555,56 +2555,52 @@ SDValue DAGTypeLegalizer::ExpandFloatOp_STORE(SDNode *N, unsigned OpNo) {
                            ST->getMemoryVT(), ST->getMemOperand());
 }
 
-SDValue DAGTypeLegalizer::ExpandFloatOp_LROUND(SDNode *N) {
+SDValue DAGTypeLegalizer::ExpandFloatOp_XRINT_XROUND(SDNode *N,
+                                                     RTLIB::Libcall LC) {
   EVT RVT = N->getValueType(0);
-  EVT RetVT = N->getOperand(0).getValueType();
+  RTLIB::LibcallImpl LCImpl = DAG.getLibcalls().getLibcallImpl(LC);
+  if (LCImpl == RTLIB::Unsupported) {
+    DAG.getContext()->emitError(Twine("no libcall available for ") +
+                                N->getOperationName(&DAG));
+    return DAG.getPOISON(RVT);
+  }
+
   TargetLowering::MakeLibCallOptions CallOptions;
-  return TLI.makeLibCall(DAG, GetFPLibCall(RetVT,
-                                           RTLIB::LROUND_F32,
-                                           RTLIB::LROUND_F64,
-                                           RTLIB::LROUND_F80,
-                                           RTLIB::LROUND_F128,
-                                           RTLIB::LROUND_PPCF128),
-                         RVT, N->getOperand(0), CallOptions, SDLoc(N)).first;
+  return TLI
+      .makeLibCall(DAG, LCImpl, RVT, N->getOperand(0), CallOptions, SDLoc(N))
+      .first;
+}
+
+SDValue DAGTypeLegalizer::ExpandFloatOp_LROUND(SDNode *N) {
+  EVT RetVT = N->getOperand(0).getValueType();
+  return ExpandFloatOp_XRINT_XROUND(
+      N, GetFPLibCall(RetVT, RTLIB::LROUND_F32, RTLIB::LROUND_F64,
+                      RTLIB::LROUND_F80, RTLIB::LROUND_F128,
+                      RTLIB::LROUND_PPCF128));
 }
 
 SDValue DAGTypeLegalizer::ExpandFloatOp_LLROUND(SDNode *N) {
-  EVT RVT = N->getValueType(0);
   EVT RetVT = N->getOperand(0).getValueType();
-  TargetLowering::MakeLibCallOptions CallOptions;
-  return TLI.makeLibCall(DAG, GetFPLibCall(RetVT,
-                                           RTLIB::LLROUND_F32,
-                                           RTLIB::LLROUND_F64,
-                                           RTLIB::LLROUND_F80,
-                                           RTLIB::LLROUND_F128,
-                                           RTLIB::LLROUND_PPCF128),
-                         RVT, N->getOperand(0), CallOptions, SDLoc(N)).first;
+  return ExpandFloatOp_XRINT_XROUND(
+      N, GetFPLibCall(RetVT, RTLIB::LLROUND_F32, RTLIB::LLROUND_F64,
+                      RTLIB::LLROUND_F80, RTLIB::LLROUND_F128,
+                      RTLIB::LLROUND_PPCF128));
 }
 
 SDValue DAGTypeLegalizer::ExpandFloatOp_LRINT(SDNode *N) {
-  EVT RVT = N->getValueType(0);
   EVT RetVT = N->getOperand(0).getValueType();
-  TargetLowering::MakeLibCallOptions CallOptions;
-  return TLI.makeLibCall(DAG, GetFPLibCall(RetVT,
-                                           RTLIB::LRINT_F32,
-                                           RTLIB::LRINT_F64,
-                                           RTLIB::LRINT_F80,
-                                           RTLIB::LRINT_F128,
-                                           RTLIB::LRINT_PPCF128),
-                         RVT, N->getOperand(0), CallOptions, SDLoc(N)).first;
+  return ExpandFloatOp_XRINT_XROUND(
+      N,
+      GetFPLibCall(RetVT, RTLIB::LRINT_F32, RTLIB::LRINT_F64, RTLIB::LRINT_F80,
+                   RTLIB::LRINT_F128, RTLIB::LRINT_PPCF128));
 }
 
 SDValue DAGTypeLegalizer::ExpandFloatOp_LLRINT(SDNode *N) {
-  EVT RVT = N->getValueType(0);
   EVT RetVT = N->getOperand(0).getValueType();
-  TargetLowering::MakeLibCallOptions CallOptions;
-  return TLI.makeLibCall(DAG, GetFPLibCall(RetVT,
-                                           RTLIB::LLRINT_F32,
-                                           RTLIB::LLRINT_F64,
-                                           RTLIB::LLRINT_F80,
-                                           RTLIB::LLRINT_F128,
-                                           RTLIB::LLRINT_PPCF128),
-                         RVT, N->getOperand(0), CallOptions, SDLoc(N)).first;
+  return ExpandFloatOp_XRINT_XROUND(
+      N, GetFPLibCall(RetVT, RTLIB::LLRINT_F32, RTLIB::LLRINT_F64,
+                      RTLIB::LLRINT_F80, RTLIB::LLRINT_F128,
+                      RTLIB::LLRINT_PPCF128));
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
index 5050c3fe5ac22..8dda352522a11 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
@@ -738,6 +738,7 @@ class LLVM_LIBRARY_VISIBILITY DAGTypeLegalizer {
   SDValue ExpandFloatOp_FCOPYSIGN(SDNode *N);
   SDValue ExpandFloatOp_FP_ROUND(SDNode *N);
   SDValue ExpandFloatOp_FP_TO_XINT(SDNode *N);
+  SDValue ExpandFloatOp_XRINT_XROUND(SDNode *N, RTLIB::Libcall LC);
   SDValue ExpandFloatOp_LROUND(SDNode *N);
   SDValue ExpandFloatOp_LLROUND(SDNode *N);
   SDValue ExpandFloatOp_LRINT(SDNode *N);
diff --git a/llvm/test/CodeGen/X86/xrint-no-libcall-error.ll b/llvm/test/CodeGen/X86/xrint-no-libcall-error.ll
index 3439fc76be722..421ddabf4099d 100644
--- a/llvm/test/CodeGen/X86/xrint-no-libcall-error.ll
+++ b/llvm/test/CodeGen/X86/xrint-no-libcall-error.ll
@@ -3,6 +3,18 @@
 ; Make sure these missing libcalls emit a proper diagnostic rather
 ; than fatal erroring.
 
+; CHECK: error: no libcall available for lrint
+define i32 @test_lrint_ppcf128(ppc_fp128 %x) nounwind {
+  %r = call i32 @llvm.lrint.i32.ppcf128(ppc_fp128 %x)
+  ret i32 %r
+}
+
+; CHECK: error: no libcall available for lround
+define i32 @test_lround_ppcf128(ppc_fp128 %x) nounwind {
+  %r = call i32 @llvm.lround.i32.ppcf128(ppc_fp128 %x)
+  ret i32 %r
+}
+
 ; CHECK: error: no libcall available for llrint
 define i64 @test_llrint_ppcf128(ppc_fp128 %x) nounwind {
   %r = call i64 @llvm.llrint.i64.ppcf128(ppc_fp128 %x)

``````````

</details>


https://github.com/llvm/llvm-project/pull/215064