release/21.x: [PowerPC][CodeGen] Expand ISD::AssertNoFPClass for ppc_fp128 (#152357)

[llvmbot]

Backport 63cc2e3

Requested by: @amy-kwan

[llvmbot]

@amy-kwan What do you think about merging this PR to the release branch?

[llvmbot]

@llvm/pr-subscribers-backend-powerpc

@llvm/pr-subscribers-llvm-selectiondag

Author: None (llvmbot)

Changes

Backport 63cc2e3

Requested by: @amy-kwan

---

Full diff: https://github.com/llvm/llvm-project/pull/153741.diff

3 Files Affected:

• (modified) llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp (+8)
• (modified) llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h (+1)
• (added) llvm/test/CodeGen/PowerPC/nofpclass.ll (+15)

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
+}

[github-actions]

@amy-kwan (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR.