[DAGTypeLegalize] Legalize ISD::POISON as ISD::UNDEF for Float Type

Legalization

Author: diggerlin

llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp

@@ -165,6 +165,7 @@ void DAGTypeLegalizer::SoftenFloatResult(SDNode *N, unsigned ResNo) {
     case ISD::STRICT_UINT_TO_FP:
     case ISD::SINT_TO_FP:
     case ISD::UINT_TO_FP:  R = SoftenFloatRes_XINT_TO_FP(N); break;
+    case ISD::POISON:
     case ISD::UNDEF:       R = SoftenFloatRes_UNDEF(N); break;
     case ISD::VAARG:       R = SoftenFloatRes_VAARG(N); break;
     case ISD::VECREDUCE_FADD:
@@ -1501,6 +1502,7 @@ void DAGTypeLegalizer::ExpandFloatResult(SDNode *N, unsigned ResNo) {
     report_fatal_error("Do not know how to expand the result of this "
                        "operator!");
     // clang-format off
+  case ISD::POISON:
   case ISD::UNDEF:        SplitRes_UNDEF(N, Lo, Hi); break;
   case ISD::SELECT:       SplitRes_Select(N, Lo, Hi); break;
   case ISD::SELECT_CC:    SplitRes_SELECT_CC(N, Lo, Hi); break;
@@ -3319,6 +3321,7 @@ void DAGTypeLegalizer::SoftPromoteHalfResult(SDNode *N, unsigned ResNo) {
   case ISD::STRICT_UINT_TO_FP:
   case ISD::SINT_TO_FP:
   case ISD::UINT_TO_FP:  R = SoftPromoteHalfRes_XINT_TO_FP(N); break;
+  case ISD::POISON:
   case ISD::UNDEF:       R = SoftPromoteHalfRes_UNDEF(N); break;
   case ISD::ATOMIC_SWAP: R = BitcastToInt_ATOMIC_SWAP(N); break;
   case ISD::VECREDUCE_FADD:

llvm/test/CodeGen/PowerPC/poison-legalization.ll

@@ -0,0 +1,11 @@
+; RUN: llc < %s -mtriple=powerpc64-unknown-linux-gnu  | FileCheck %s
+
+define void @ExpandFloat(ptr %p1 )  {
+; CHECK:      stfd 0, 8(3) 
+; CHECK-NEXT: stfd 0, 0(3)
+; CHECK-NEXT: blr
+entry:
+   store volatile ppc_fp128 poison, ptr %p1
+   ret void
+}
+

llvm/test/CodeGen/RISCV/poison-legalization.ll

@@ -0,0 +1,24 @@
+; RUN: llc < %s -mtriple=riscv32  | FileCheck %s
+
+define void @SoftenFloat(ptr %p1)  {
+; CHECK-LABEL: SoftenFloat:
+; CHECK:       # %bb.0:                                # %entry
+; CHECK-NEXT:     sw      a0, 4(a0)
+; CHECK-NEXT:     sw      a0, 0(a0)
+; CHECK-NEXT:     ret
+
+entry:
+  store volatile double poison, ptr %p1
+  ret void
+}
+
+define void @PromoteHalf(ptr %p1 )  {
+; CHECK-LABEL: PromoteHalf:
+; CHECK:       # %bb.0:                                # %entry
+; CHECK-NEXT:     sh      a0, 0(a0)
+; CHECK-NEXT:     ret
+entry:
+   store volatile half poison, ptr %p1
+   ret void
+}
+