This code implements most of mips16 hardfloat as it is done by gcc.

In this case, essentially it is soft float with different library routines.
The next step will be to make this fully interoperational with mips32 floating
point and that requires creating stubs for functions with signatures that
contain floating point types.

I have a more sophisticated design for mips16 hardfloat which I hope to
implement at a later time that directly does floating point without the need
for function calls.

The mips16 encoding has no floating point instructions so one needs to
switch to mips32 mode to execute floating point instructions.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170259 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 46 insertions, 0 deletions

diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp
index 34eb4a609e..3fad6eec92 100644
--- a/lib/Target/Mips/MipsISelLowering.cpp
+++ b/lib/Target/Mips/MipsISelLowering.cpp
@@ -50,6 +50,13 @@ static cl::opt<bool>
 LargeGOT("mxgot", cl::Hidden,
          cl::desc("MIPS: Enable GOT larger than 64k."), cl::init(false));
 
+static cl::opt<bool>
+Mips16HardFloat("mips16-hard-float", cl::NotHidden,
+                cl::desc("MIPS: mips16 hard float enable."),
+                cl::init(false));
+
+
+
 static const uint16_t O32IntRegs[4] = {
   Mips::A0, Mips::A1, Mips::A2, Mips::A3
 };
@@ -198,6 +205,41 @@ const char *MipsTargetLowering::getTargetNodeName(unsigned Opcode) const {
   }
 }
 
+void MipsTargetLowering::setMips16HardFloatLibCalls() {
+  setLibcallName(RTLIB::ADD_F32, "__mips16_addsf3");
+  setLibcallName(RTLIB::ADD_F64, "__mips16_adddf3");
+  setLibcallName(RTLIB::SUB_F32, "__mips16_subsf3");
+  setLibcallName(RTLIB::SUB_F64, "__mips16_subdf3");
+  setLibcallName(RTLIB::MUL_F32, "__mips16_mulsf3");
+  setLibcallName(RTLIB::MUL_F64, "__mips16_muldf3");
+  setLibcallName(RTLIB::DIV_F32, "__mips16_divsf3");
+  setLibcallName(RTLIB::DIV_F64, "__mips16_divdf3");
+  setLibcallName(RTLIB::FPEXT_F32_F64, "__mips16_extendsfdf2");
+  setLibcallName(RTLIB::FPROUND_F64_F32, "__mips16_truncdfsf2");
+  setLibcallName(RTLIB::FPTOSINT_F32_I32, "__mips16_fix_truncsfsi");
+  setLibcallName(RTLIB::FPTOSINT_F64_I32, "__mips16_fix_truncdfsi");
+  setLibcallName(RTLIB::SINTTOFP_I32_F32, "__mips16_floatsisf");
+  setLibcallName(RTLIB::SINTTOFP_I32_F64, "__mips16_floatsidf");
+  setLibcallName(RTLIB::UINTTOFP_I32_F32, "__mips16_floatunsisf");
+  setLibcallName(RTLIB::UINTTOFP_I32_F64, "__mips16_floatunsidf");
+  setLibcallName(RTLIB::OEQ_F32, "__mips16_eqsf2");
+  setLibcallName(RTLIB::OEQ_F64, "__mips16_eqdf2");
+  setLibcallName(RTLIB::UNE_F32, "__mips16_nesf2");
+  setLibcallName(RTLIB::UNE_F64, "__mips16_nedf2");
+  setLibcallName(RTLIB::OGE_F32, "__mips16_gesf2");
+  setLibcallName(RTLIB::OGE_F64, "__mips16_gedf2");
+  setLibcallName(RTLIB::OLT_F32, "__mips16_ltsf2");
+  setLibcallName(RTLIB::OLT_F64, "__mips16_ltdf2");
+  setLibcallName(RTLIB::OLE_F32, "__mips16_lesf2");
+  setLibcallName(RTLIB::OLE_F64, "__mips16_ledf2");
+  setLibcallName(RTLIB::OGT_F32, "__mips16_gtsf2");
+  setLibcallName(RTLIB::OGT_F64, "__mips16_gtdf2");
+  setLibcallName(RTLIB::UO_F32, "__mips16_unordsf2");
+  setLibcallName(RTLIB::UO_F64, "__mips16_unorddf2");
+  setLibcallName(RTLIB::O_F32, "__mips16_unordsf2");
+  setLibcallName(RTLIB::O_F64, "__mips16_unorddf2");
+}
+
 MipsTargetLowering::
 MipsTargetLowering(MipsTargetMachine &TM)
   : TargetLowering(TM, new MipsTargetObjectFile()),
@@ -218,6 +260,8 @@ MipsTargetLowering(MipsTargetMachine &TM)
 
   if (Subtarget->inMips16Mode()) {
     addRegisterClass(MVT::i32, &Mips::CPU16RegsRegClass);
+    if (Mips16HardFloat)
+      setMips16HardFloatLibCalls();
   }
 
   if (Subtarget->hasDSP()) {
diff --git a/lib/Target/Mips/MipsISelLowering.h b/lib/Target/Mips/MipsISelLowering.h
index ff25df94e3..c4b38c66ee 100644
--- a/lib/Target/Mips/MipsISelLowering.h
+++ b/lib/Target/Mips/MipsISelLowering.h
@@ -174,6 +174,8 @@ namespace llvm {
     virtual SDValue PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const;
   private:
 
+    void setMips16HardFloatLibCalls();
+
     /// ByValArgInfo - Byval argument information.
     struct ByValArgInfo {
       unsigned FirstIdx; // Index of the first register used.