GlobalISel: Allow legalizing G_FADD to a libcall

Use the same handling in the generic legalizer code as for the other
libcalls (G_FREM, G_FPOW).

Enable it on ARM for float and double so we can test it.

llvm-svn: 299931

2 files changed, 7 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index afab23d94f0..20358f7ee6c 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -66,6 +66,9 @@ void LegalizerHelper::extractParts(unsigned Reg, LLT Ty, int NumParts,
 
 static RTLIB::Libcall getRTLibDesc(unsigned Opcode, unsigned Size) {
   switch (Opcode) {
+  case TargetOpcode::G_FADD:
+    assert((Size == 32 || Size == 64) && "Unsupported size");
+    return Size == 64 ? RTLIB::ADD_F64 : RTLIB::ADD_F32;
   case TargetOpcode::G_FREM:
     return Size == 64 ? RTLIB::REM_F64 : RTLIB::REM_F32;
   case TargetOpcode::G_FPOW:
@@ -83,6 +86,7 @@ LegalizerHelper::libcall(MachineInstr &MI) {
   switch (MI.getOpcode()) {
   default:
     return UnableToLegalize;
+  case TargetOpcode::G_FADD:
   case TargetOpcode::G_FPOW:
   case TargetOpcode::G_FREM: {
     auto &Ctx = MIRBuilder.getMF().getFunction()->getContext();
diff --git a/llvm/lib/Target/ARM/ARMLegalizerInfo.cpp b/llvm/lib/Target/ARM/ARMLegalizerInfo.cpp
index a1097af6e85..994bbd673dd 100644
--- a/llvm/lib/Target/ARM/ARMLegalizerInfo.cpp
+++ b/llvm/lib/Target/ARM/ARMLegalizerInfo.cpp
@@ -63,6 +63,9 @@ ARMLegalizerInfo::ARMLegalizerInfo(const ARMSubtarget &ST) {
 
     setAction({G_LOAD, s64}, Legal);
     setAction({G_STORE, s64}, Legal);
+  } else {
+    for (auto Ty : {s32, s64})
+      setAction({G_FADD, Ty}, Libcall);
   }
 
   for (unsigned Op : {G_FREM, G_FPOW})