https://github.com/llvmbot created
https://github.com/llvm/llvm-project/pull/153741
Backport 63cc2e390db57cbc400b519771b7005eab1fc76a
Requested by: @amy-kwan
>From a79b842082a9e98c55e22385121871cbad6371c2 Mon Sep 17 00:00:00 2001
From: Amy Kwan <amy.kw...@ibm.com>
Date: Wed, 13 Aug 2025 15:00:32 -0400
Subject: [PATCH] [PowerPC][CodeGen] Expand ISD::AssertNoFPClass for ppc_fp128
(#152357)
780054d3ff18075a6bc433029f336931792b1d2d added support for
`ISD::AssertNoFPClass`.
This ISD node can be used with the `ppc_fp128` type, which is really
just two `f64s` and requires expanding when used with
`ISD::AssertNoFPClass`. Without the support for expanding the result, we
get an assertion because the legalizer does not know how to expand the
results of `ppc_fp128` with `ISD::AssertNoFPClass`.
```
ExpandFloatResult #0: t7: ppcf128 = AssertNoFPClass t5, TargetConstant:i32<3>
LLVM ERROR: Do not know how to expand the result of this operator!
```
Thus, this patch aims to add support for the expand so we no longer
assert.
This fixes #151375.
(cherry picked from commit 63cc2e390db57cbc400b519771b7005eab1fc76a)
---
.../CodeGen/SelectionDAG/LegalizeFloatTypes.cpp | 8 ++++++++
llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h | 1 +
llvm/test/CodeGen/PowerPC/nofpclass.ll | 15 +++++++++++++++
3 files changed, 24 insertions(+)
create mode 100644 llvm/test/CodeGen/PowerPC/nofpclass.ll
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
b/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
index 2cad36eff9c88..fe357106bda60 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
@@ -1551,6 +1551,7 @@ void DAGTypeLegalizer::ExpandFloatResult(SDNode *N,
unsigned ResNo) {
case ISD::VAARG: ExpandRes_VAARG(N, Lo, Hi); break;
case ISD::ConstantFP: ExpandFloatRes_ConstantFP(N, Lo, Hi); break;
+ case ISD::AssertNoFPClass: ExpandFloatRes_AssertNoFPClass(N, Lo, Hi); break;
case ISD::FABS: ExpandFloatRes_FABS(N, Lo, Hi); break;
case ISD::STRICT_FMINNUM:
case ISD::FMINNUM: ExpandFloatRes_FMINNUM(N, Lo, Hi); break;
@@ -1966,6 +1967,13 @@ void DAGTypeLegalizer::ExpandFloatRes_FNEG(SDNode *N,
SDValue &Lo,
Hi = DAG.getNode(ISD::FNEG, dl, Hi.getValueType(), Hi);
}
+void DAGTypeLegalizer::ExpandFloatRes_AssertNoFPClass(SDNode *N, SDValue &Lo,
+ SDValue &Hi) {
+ // TODO: Handle ppcf128 by preserving AssertNoFPClass for one of the halves.
+ SDLoc dl(N);
+ GetExpandedFloat(N->getOperand(0), Lo, Hi);
+}
+
void DAGTypeLegalizer::ExpandFloatRes_FP_EXTEND(SDNode *N, SDValue &Lo,
SDValue &Hi) {
EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), N->getValueType(0));
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
index 9b537248d4ab4..4eaa79890e005 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
@@ -677,6 +677,7 @@ class LLVM_LIBRARY_VISIBILITY DAGTypeLegalizer {
SDNode *N, RTLIB::Libcall LC, std::optional<unsigned> CallRetResNo = {});
// clang-format off
+ void ExpandFloatRes_AssertNoFPClass(SDNode *N, SDValue &Lo, SDValue &Hi);
void ExpandFloatRes_FABS (SDNode *N, SDValue &Lo, SDValue &Hi);
void ExpandFloatRes_FACOS (SDNode *N, SDValue &Lo, SDValue &Hi);
void ExpandFloatRes_FASIN (SDNode *N, SDValue &Lo, SDValue &Hi);
diff --git a/llvm/test/CodeGen/PowerPC/nofpclass.ll
b/llvm/test/CodeGen/PowerPC/nofpclass.ll
new file mode 100644
index 0000000000000..b08e810cd1cca
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/nofpclass.ll
@@ -0,0 +1,15 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
UTC_ARGS: --version 5
+; RUN: llc -mtriple=powerpc64le-unknown-linux-gnu < %s | FileCheck %s
+; RUN: llc -mtriple=powerpc64-ibm-aix-xcoff < %s | FileCheck %s
+
+; TODO: Update this test after adding the proper expansion of nofpclass for
+; ppc_fp128 to test with more masks and to demonstrate preserving nofpclass
+; after legalization.
+
+define ppc_fp128 @f(ppc_fp128 nofpclass(nan) %s) {
+; CHECK-LABEL: f:
+; CHECK: # %bb.0: # %entry
+; CHECK-NEXT: blr
+entry:
+ ret ppc_fp128 %s
+}
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