Do Materialize Floating Point in Mips Fast-Isel

[rkotler]

Summary

Implement materialize of floating point literals in Mips Fast-Isel

Reopened version of D3659

[dsanders]

LGTM.

I agree that the changes I requested in D3659 have been dealt with (or were rendered irrelevant by earlier commits).

lib/Target/Mips/MipsFastISel.cpp

unsigned MipsFastISel::TargetMaterializeConstant(const Constant *C) {
   return 0;
 }
 
 bool MipsFastISel::EmitStore(MVT VT, unsigned SrcReg, Address &Addr,
                              unsigned Alignment) {
   //
   // more cases will be handled here in following patches.
   //
-  if (VT != MVT::i32)
-    return false;
+  if (VT == MVT::i32)
     EmitInstStore(Mips::SW, SrcReg, Addr.Base.Reg, Addr.Offset);
+  else if (VT == MVT::f32)
+    EmitInstStore(Mips::SWC1, SrcReg, Addr.Base.Reg, Addr.Offset);
+  else if (VT == MVT::f64)
+    EmitInstStore(Mips::SDC1, SrcReg, Addr.Base.Reg, Addr.Offset);
+  else
+    return false;
   return true;
 }
 
 bool MipsFastISel::SelectStore(const Instruction *I) {
   Value *Op0 = I->getOperand(0);
   unsigned SrcReg = 0;
 
   // Atomic stores need special handling.
bool MipsFastISel::TargetSelectInstruction(const Instruction *I) {
   case Instruction::Ret:
     return SelectRet(I);
   }
   return false;
 }
 }
 
 unsigned MipsFastISel::MaterializeFP(const ConstantFP *CFP, MVT VT) {
+  int64_t Imm = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
+  if (VT == MVT::f32) {
+    const TargetRegisterClass *RC = &Mips::FGR32RegClass;
+    unsigned DestReg = createResultReg(RC);
+    unsigned TempReg = Materialize32BitInt(Imm, &Mips::GPR32RegClass);
+    EmitInst(Mips::MTC1, DestReg).addReg(TempReg);
+    return DestReg;
+  } else if (VT == MVT::f64) {
+    const TargetRegisterClass *RC = &Mips::AFGR64RegClass;
+    unsigned DestReg = createResultReg(RC);
+    unsigned TempReg1 = Materialize32BitInt(Imm >> 32, &Mips::GPR32RegClass);
+    unsigned TempReg2 =
+        Materialize32BitInt(Imm & 0xFFFFFFFF, &Mips::GPR32RegClass);
+    EmitInst(Mips::BuildPairF64, DestReg).addReg(TempReg2).addReg(TempReg1);
+    return DestReg;
+  }
   return 0;
 }
 
 unsigned MipsFastISel::MaterializeGV(const GlobalValue *GV, MVT VT) {
   // For now 32-bit only.
   if (VT != MVT::i32)
     return 0;
   const TargetRegisterClass *RC = &Mips::GPR32RegClass;

test/CodeGen/Mips/Fast-ISel/simplestorefp1.ll

+; RUN: llc -march=mipsel -relocation-model=pic -O0 -mips-fast-isel -fast-isel-abort -mcpu=mips32r2 \
+; RUN:     < %s | FileCheck %s
+
+@f = common global float 0.000000e+00, align 4
+@de = common global double 0.000000e+00, align 8
+
+; Function Attrs: nounwind
+define void @f1() #0 {
+entry:
+  store float 0x3FFA76C8C0000000, float* @f, align 4
+  ret void
+; CHECK:  .ent  f1
+; CHECK:  lui  $[[REG1:[0-9]+]], 16339
+; CHECK:  ori  $[[REG2:[0-9]+]], $[[REG1]], 46662
+; CHECK:  mtc1  $[[REG2]], $f[[REG3:[0-9]+]]
+; CHECK:  lw  $[[REG4:[0-9]+]], %got(f)(${{[0-9]+}})
+; CHECK:  swc1  $f[[REG3]], 0($[[REG4]])
+; CHECK:   .end  f1
+
+}
+
+; Function Attrs: nounwind
+define void @d1() #0 {
+entry:
+  store double 1.234567e+00, double* @de, align 8
+; CHECK:  .ent  d1
+; CHECK:  lui  $[[REG1a:[0-9]+]], 16371
+; CHECK:  ori  $[[REG2a:[0-9]+]], $[[REG1a]], 49353
+; CHECK:  lui  $[[REG1b:[0-9]+]], 21403
+; CHECK:  ori  $[[REG2b:[0-9]+]], $[[REG1b]], 34951
+; CHECK:  mtc1  $[[REG2b]], $f[[REG3b:[0-9]+]]
+; CHECK:  mtc1  $[[REG2a]], $f[[REG3a:[0-9]+]]
+; CHECK:  sdc1  $f[[REG3b]], 0(${{[0-9]+}})
+; CHECK:  .end  d1
+  ret void
+}
+
+attributes #0 = { nounwind "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }