Implement floating point compare for mips fast-isel

[rkotler]

Summary

Expand SelectCmp to handle floating point compare

[dsanders]

I'm holding back on the conditional LGTM for now since I would like to see how you solve the 64-bit FPU cases both here and in D5562 first.

lib/Target/Mips/MipsFastISel.cpp

625

C_EQ_D32 needs to be C_EQ_D64 for 64-bit FPU's and we don't guard against this.

Similarly for the other compares.

640–647

These two aren't correct when one of the operands is NaN. 'NaN ogt 0.0' is false because they are unordered, but '!(NaN ole 0.0)' is true. Swap the LHS/RHS instead.

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

21

We ought to check that the registers are in the right order.

Likewise for the tests below.

[rkotler]

Fix patch per pre-commit recommendations.

[dsanders]

lib/Target/Mips/MipsFastISel.cpp

640–647

After chatting with Reed, I've taken a look at the SelectionDAG implementation and found that it is using c.ule.[ds] and c.ule.[ds] for FCMP_OGT and FCMP_OGE respectively and then inverting the boolean result before the value is consumed. This is valid too and we should probably go with that for the sake of consistency.

[dsanders]

LGTM with one new formatting nit.

lib/Target/Mips/MipsFastISel.cpp

625

Done

640–647

Done

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

20–27

Formatting nit: Could you line up the start of each instruction?

Likewise below

21

Done

[rkotler]

Make instructions line up properly in the test case.

lib/Target/Mips/MipsFastISel.cpp

bool MipsFastISel::SelectCmp(const Instruction *I) {
 
   unsigned LeftReg = getRegEnsuringSimpleIntegerWidening(Left, IsUnsigned);
   if (LeftReg == 0)
     return false;
   unsigned RightReg = getRegEnsuringSimpleIntegerWidening(Right, IsUnsigned);
   if (RightReg == 0)
     return false;
   unsigned ResultReg = createResultReg(&Mips::GPR32RegClass);
-
-  switch (CI->getPredicate()) {
+  CmpInst::Predicate P = CI->getPredicate();
+  switch (P) {
   default:
     return false;
   case CmpInst::ICMP_EQ: {
     unsigned TempReg = createResultReg(&Mips::GPR32RegClass);
     EmitInst(Mips::XOR, TempReg).addReg(LeftReg).addReg(RightReg);
     EmitInst(Mips::SLTiu, ResultReg).addReg(TempReg).addImm(1);
     break;
   }
bool MipsFastISel::SelectCmp(const Instruction *I) {
   case CmpInst::ICMP_SGT: {
     EmitInst(Mips::SLT, ResultReg).addReg(RightReg).addReg(LeftReg);
     break;
   }
   case CmpInst::ICMP_SLT: {
     EmitInst(Mips::SLT, ResultReg).addReg(LeftReg).addReg(RightReg);
     break;
   }
   case CmpInst::ICMP_SGE: {
     unsigned TempReg = createResultReg(&Mips::GPR32RegClass);
     EmitInst(Mips::SLT, TempReg).addReg(LeftReg).addReg(RightReg);
     EmitInst(Mips::XORi, ResultReg).addReg(TempReg).addImm(1);
     break;
   }
   case CmpInst::ICMP_SLE: {
     unsigned TempReg = createResultReg(&Mips::GPR32RegClass);
     EmitInst(Mips::SLT, TempReg).addReg(RightReg).addReg(LeftReg);
     EmitInst(Mips::XORi, ResultReg).addReg(TempReg).addImm(1);
     break;
   }
+  case CmpInst::FCMP_OEQ:
+  case CmpInst::FCMP_UNE:
+  case CmpInst::FCMP_OLT:
+  case CmpInst::FCMP_OLE:
+  case CmpInst::FCMP_OGT:
+  case CmpInst::FCMP_OGE: {
+    if (UnsupportedFPMode)
+      return false;
+    bool IsFloat = Left->getType()->isFloatTy();
+    bool IsDouble = Left->getType()->isDoubleTy();
+    if (!IsFloat && !IsDouble)
+      return false;
+    unsigned Opc, CondMovOpc;
+    switch (P) {
+    case CmpInst::FCMP_OEQ:
+      Opc = IsFloat ? Mips::C_EQ_S : Mips::C_EQ_D32;
+      CondMovOpc = Mips::MOVT_I;
+      break;
+    case CmpInst::FCMP_UNE:
+      Opc = IsFloat ? Mips::C_EQ_S : Mips::C_EQ_D32;
+      CondMovOpc = Mips::MOVF_I;
+      break;
+    case CmpInst::FCMP_OLT:
+      Opc = IsFloat ? Mips::C_OLT_S : Mips::C_OLT_D32;
+      CondMovOpc = Mips::MOVT_I;
+      break;
+    case CmpInst::FCMP_OLE:
+      Opc = IsFloat ? Mips::C_OLE_S : Mips::C_OLE_D32;
+      CondMovOpc = Mips::MOVT_I;
+      break;
+    case CmpInst::FCMP_OGT:
+      Opc = IsFloat ? Mips::C_ULE_S : Mips::C_ULE_D32;
+      CondMovOpc = Mips::MOVF_I;
+      break;
+    case CmpInst::FCMP_OGE:
+      Opc = IsFloat ? Mips::C_ULT_S : Mips::C_ULT_D32;
+      CondMovOpc = Mips::MOVF_I;
+      break;
+    default:
+      break;
+    }
+    unsigned RegWithZero = createResultReg(&Mips::GPR32RegClass);
+    unsigned RegWithOne = createResultReg(&Mips::GPR32RegClass);
+    EmitInst(Mips::ADDiu, RegWithZero).addReg(Mips::ZERO).addImm(0);
+    EmitInst(Mips::ADDiu, RegWithOne).addReg(Mips::ZERO).addImm(1);
+    EmitInst(Opc).addReg(LeftReg).addReg(RightReg).addReg(
+        Mips::FCC0, RegState::ImplicitDefine);
+    MachineInstrBuilder MI = EmitInst(CondMovOpc, ResultReg)
+                                 .addReg(RegWithOne)
+                                 .addReg(Mips::FCC0)
+                                 .addReg(RegWithZero, RegState::Implicit);
+    MI->tieOperands(0, 3);
+    break;
+  }
   }
   updateValueMap(I, ResultReg);
   return true;
 }
 
 bool MipsFastISel::fastSelectInstruction(const Instruction *I) {
   if (!TargetSupported)
     return false;

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

+; RUN: llc -march=mipsel -relocation-model=pic -O0 -mips-fast-isel -fast-isel-abort -mcpu=mips32r2 \
+; RUN:     < %s | FileCheck %s
+; RUN: llc -march=mipsel -relocation-model=pic -O0 -mips-fast-isel -fast-isel-abort -mcpu=mips32 \
+; RUN:     < %s | FileCheck %s
+
+@f1 = common global float 0.000000e+00, align 4
+@f2 = common global float 0.000000e+00, align 4
+@b1 = common global i32 0, align 4
+@d1 = common global double 0.000000e+00, align 8
+@d2 = common global double 0.000000e+00, align 8
+
+; Function Attrs: nounwind
+define void @feq1()  {
+entry:
+  %0 = load float* @f1, align 4
+  %1 = load float* @f2, align 4
+  %cmp = fcmp oeq float %0, %1
+; CHECK-LABEL:  feq1:
+; CHECK-DAG:    lw      $[[REG_F2_GOT:[0-9]+]], %got(f2)(${{[0-9]+}})
+; CHECK-DAG:    lw      $[[REG_F1_GOT:[0-9]+]], %got(f1)(${{[0-9]+}})
+; CHECK-DAG:    lwc1    $f[[REG_F2:[0-9]+]], 0($[[REG_F2_GOT]])
+; CHECK-DAG:    lwc1    $f[[REG_F1:[0-9]+]], 0($[[REG_F1_GOT]])
+; CHECK-DAG:    addiu   $[[REG_ZERO:[0-9]+]], $zero, 0
+; CHECK-DAG:    addiu   $[[REG_ONE:[0-9]+]], $zero, 1
+; CHECK:        c.eq.s  $f[[REG_F1]], $f[[REG_F2]]
+; CHECK:        movt  $[[REG_ZERO]], $[[REG_ONE]], $fcc0
+
+  %conv = zext i1 %cmp to i32
+  store i32 %conv, i32* @b1, align 4
+  ret void
+}
+
+; Function Attrs: nounwind
+define void @fne1()  {
+entry:
+  %0 = load float* @f1, align 4
+  %1 = load float* @f2, align 4
+  %cmp = fcmp une float %0, %1
+; CHECK-LABEL:  fne1:
+; CHECK-DAG:    lw      $[[REG_F2_GOT:[0-9]+]], %got(f2)(${{[0-9]+}})
+; CHECK-DAG:    lw      $[[REG_F1_GOT:[0-9]+]], %got(f1)(${{[0-9]+}})
+; CHECK-DAG:    lwc1    $f[[REG_F2:[0-9]+]], 0($[[REG_F2_GOT]])
+; CHECK-DAG:    lwc1    $f[[REG_F1:[0-9]+]], 0($[[REG_F1_GOT]])
+; CHECK-DAG:    addiu   $[[REG_ZERO:[0-9]+]], $zero, 0
+; CHECK-DAG:    addiu   $[[REG_ONE:[0-9]+]], $zero, 1
+; CHECK:        c.eq.s  $f[[REG_F1]], $f[[REG_F2]]
+; CHECK:        movf  $[[REG_ZERO]], $[[REG_ONE]], $fcc0
+  %conv = zext i1 %cmp to i32
+  store i32 %conv, i32* @b1, align 4
+  ret void
+}
+
+; Function Attrs: nounwind
+define void @flt1()  {
+entry:
+  %0 = load float* @f1, align 4
+  %1 = load float* @f2, align 4
+  %cmp = fcmp olt float %0, %1
+; CHECK-LABEL:  flt1:
+; CHECK-DAG:    lw      $[[REG_F2_GOT:[0-9]+]], %got(f2)(${{[0-9]+}})
+; CHECK-DAG:    lw      $[[REG_F1_GOT:[0-9]+]], %got(f1)(${{[0-9]+}})
+; CHECK-DAG:    lwc1    $f[[REG_F2:[0-9]+]], 0($[[REG_F2_GOT]])
+; CHECK-DAG:    lwc1    $f[[REG_F1:[0-9]+]], 0($[[REG_F1_GOT]])
+; CHECK-DAG:    addiu   $[[REG_ZERO:[0-9]+]], $zero, 0
+; CHECK-DAG:    addiu   $[[REG_ONE:[0-9]+]], $zero, 1
+; CHECK:        c.olt.s  $f[[REG_F1]], $f[[REG_F2]]
+; CHECK:        movt  $[[REG_ZERO]], $[[REG_ONE]], $fcc0
+
+  %conv = zext i1 %cmp to i32
+  store i32 %conv, i32* @b1, align 4
+  ret void
+}
+
+; Function Attrs: nounwind
+define void @fgt1()  {
+entry:
+  %0 = load float* @f1, align 4
+  %1 = load float* @f2, align 4
+  %cmp = fcmp ogt float %0, %1
+; CHECK-LABEL: fgt1:
+; CHECK-DAG:    lw      $[[REG_F2_GOT:[0-9]+]], %got(f2)(${{[0-9]+}})
+; CHECK-DAG:    lw      $[[REG_F1_GOT:[0-9]+]], %got(f1)(${{[0-9]+}})
+; CHECK-DAG:    lwc1    $f[[REG_F2:[0-9]+]], 0($[[REG_F2_GOT]])
+; CHECK-DAG:    lwc1    $f[[REG_F1:[0-9]+]], 0($[[REG_F1_GOT]])
+; CHECK-DAG:    addiu   $[[REG_ZERO:[0-9]+]], $zero, 0
+; CHECK-DAG:    addiu   $[[REG_ONE:[0-9]+]], $zero, 1
+; CHECK:        c.ule.s  $f[[REG_F1]], $f[[REG_F2]]
+; CHECK:        movf  $[[REG_ZERO]], $[[REG_ONE]], $fcc0
+  %conv = zext i1 %cmp to i32
+  store i32 %conv, i32* @b1, align 4
+  ret void
+}
+
+; Function Attrs: nounwind
+define void @fle1()  {
+entry:
+  %0 = load float* @f1, align 4
+  %1 = load float* @f2, align 4
+  %cmp = fcmp ole float %0, %1
+; CHECK-LABEL:  fle1:
+; CHECK-DAG:    lw      $[[REG_F2_GOT:[0-9]+]], %got(f2)(${{[0-9]+}})
+; CHECK-DAG:    lw      $[[REG_F1_GOT:[0-9]+]], %got(f1)(${{[0-9]+}})
+; CHECK-DAG:    lwc1    $f[[REG_F2:[0-9]+]], 0($[[REG_F2_GOT]])
+; CHECK-DAG:    lwc1    $f[[REG_F1:[0-9]+]], 0($[[REG_F1_GOT]])
+; CHECK-DAG:    addiu   $[[REG_ZERO:[0-9]+]], $zero, 0
+; CHECK-DAG:    addiu   $[[REG_ONE:[0-9]+]], $zero, 1
+; CHECK:        c.ole.s  $f[[REG_F1]], $f[[REG_F2]]
+; CHECK:        movt  $[[REG_ZERO]], $[[REG_ONE]], $fcc0
+  %conv = zext i1 %cmp to i32
+  store i32 %conv, i32* @b1, align 4
+  ret void
+}
+
+; Function Attrs: nounwind
+define void @fge1()  {
+entry:
+  %0 = load float* @f1, align 4
+  %1 = load float* @f2, align 4
+  %cmp = fcmp oge float %0, %1
+; CHECK-LABEL:  fge1:
+; CHECK-DAG:    lw      $[[REG_F2_GOT:[0-9]+]], %got(f2)(${{[0-9]+}})
+; CHECK-DAG:    lw      $[[REG_F1_GOT:[0-9]+]], %got(f1)(${{[0-9]+}})
+; CHECK-DAG:    lwc1    $f[[REG_F2:[0-9]+]], 0($[[REG_F2_GOT]])
+; CHECK-DAG:    lwc1    $f[[REG_F1:[0-9]+]], 0($[[REG_F1_GOT]])
+; CHECK-DAG:    addiu   $[[REG_ZERO:[0-9]+]], $zero, 0
+; CHECK-DAG:    addiu   $[[REG_ONE:[0-9]+]], $zero, 1
+; CHECK:        c.ult.s  $f[[REG_F1]], $f[[REG_F2]]
+; CHECK:        movf  $[[REG_ZERO]], $[[REG_ONE]], $fcc0
+  %conv = zext i1 %cmp to i32
+  store i32 %conv, i32* @b1, align 4
+  ret void
+}
+
+; Function Attrs: nounwind
+define void @deq1()  {
+entry:
+  %0 = load double* @d1, align 8
+  %1 = load double* @d2, align 8
+  %cmp = fcmp oeq double %0, %1
+; CHECK-LABEL:  deq1:
+; CHECK-DAG:    lw      $[[REG_D2_GOT:[0-9]+]], %got(d2)(${{[0-9]+}})
+; CHECK-DAG:    lw      $[[REG_D1_GOT:[0-9]+]], %got(d1)(${{[0-9]+}})
+; CHECK-DAG:    ldc1    $f[[REG_D2:[0-9]+]], 0($[[REG_D2_GOT]])
+; CHECK-DAG:    ldc1    $f[[REG_D1:[0-9]+]], 0($[[REG_D1_GOT]])
+; CHECK-DAG:    addiu   $[[REG_ZERO:[0-9]+]], $zero, 0
+; CHECK-DAG:    addiu   $[[REG_ONE:[0-9]+]], $zero, 1
+; CHECK:        c.eq.d  $f[[REG_D1]], $f[[REG_D2]]
+; CHECK:        movt  $[[REG_ZERO]], $[[REG_ONE]], $fcc0
+  %conv = zext i1 %cmp to i32
+  store i32 %conv, i32* @b1, align 4
+  ret void
+}
+
+; Function Attrs: nounwind
+define void @dne1()  {
+entry:
+  %0 = load double* @d1, align 8
+  %1 = load double* @d2, align 8
+  %cmp = fcmp une double %0, %1
+; CHECK-LABEL:  dne1:
+; CHECK-DAG:    lw      $[[REG_D2_GOT:[0-9]+]], %got(d2)(${{[0-9]+}})
+; CHECK-DAG:    lw      $[[REG_D1_GOT:[0-9]+]], %got(d1)(${{[0-9]+}})
+; CHECK-DAG:    ldc1    $f[[REG_D2:[0-9]+]], 0($[[REG_D2_GOT]])
+; CHECK-DAG:    ldc1    $f[[REG_D1:[0-9]+]], 0($[[REG_D1_GOT]])
+; CHECK-DAG:    addiu   $[[REG_ZERO:[0-9]+]], $zero, 0
+; CHECK-DAG:    addiu   $[[REG_ONE:[0-9]+]], $zero, 1
+; CHECK:        c.eq.d  $f[[REG_D1]], $f[[REG_D2]]
+; CHECK:        movf  $[[REG_ZERO]], $[[REG_ONE]], $fcc0
+  %conv = zext i1 %cmp to i32
+  store i32 %conv, i32* @b1, align 4
+  ret void
+}
+
+; Function Attrs: nounwind
+define void @dlt1()  {
+entry:
+  %0 = load double* @d1, align 8
+  %1 = load double* @d2, align 8
+  %cmp = fcmp olt double %0, %1
+; CHECK-LABEL:  dlt1:
+; CHECK-DAG:    lw      $[[REG_D2_GOT:[0-9]+]], %got(d2)(${{[0-9]+}})
+; CHECK-DAG:    lw      $[[REG_D1_GOT:[0-9]+]], %got(d1)(${{[0-9]+}})
+; CHECK-DAG:    ldc1    $f[[REG_D2:[0-9]+]], 0($[[REG_D2_GOT]])
+; CHECK-DAG:    ldc1    $f[[REG_D1:[0-9]+]], 0($[[REG_D1_GOT]])
+; CHECK-DAG:    addiu   $[[REG_ZERO:[0-9]+]], $zero, 0
+; CHECK-DAG:    addiu   $[[REG_ONE:[0-9]+]], $zero, 1
+; CHECK:        c.olt.d  $f[[REG_D1]], $f[[REG_D2]]
+; CHECK:        movt  $[[REG_ZERO]], $[[REG_ONE]], $fcc0
+  %conv = zext i1 %cmp to i32
+  store i32 %conv, i32* @b1, align 4
+  ret void
+}
+
+; Function Attrs: nounwind
+define void @dgt1()  {
+entry:
+  %0 = load double* @d1, align 8
+  %1 = load double* @d2, align 8
+  %cmp = fcmp ogt double %0, %1
+; CHECK-LABEL:  dgt1:
+; CHECK-DAG:    lw      $[[REG_D2_GOT:[0-9]+]], %got(d2)(${{[0-9]+}})
+; CHECK-DAG:    lw      $[[REG_D1_GOT:[0-9]+]], %got(d1)(${{[0-9]+}})
+; CHECK-DAG:    ldc1    $f[[REG_D2:[0-9]+]], 0($[[REG_D2_GOT]])
+; CHECK-DAG:    ldc1    $f[[REG_D1:[0-9]+]], 0($[[REG_D1_GOT]])
+; CHECK-DAG:    addiu   $[[REG_ZERO:[0-9]+]], $zero, 0
+; CHECK-DAG:    addiu   $[[REG_ONE:[0-9]+]], $zero, 1
+; CHECK:        c.ule.d  $f[[REG_D1]], $f[[REG_D2]]
+; CHECK:        movf  $[[REG_ZERO]], $[[REG_ONE]], $fcc0
+  %conv = zext i1 %cmp to i32
+  store i32 %conv, i32* @b1, align 4
+  ret void
+}
+
+; Function Attrs: nounwind
+define void @dle1()  {
+entry:
+  %0 = load double* @d1, align 8
+  %1 = load double* @d2, align 8
+  %cmp = fcmp ole double %0, %1
+; CHECK-LABEL:  dle1:
+; CHECK-DAG:    lw      $[[REG_D2_GOT:[0-9]+]], %got(d2)(${{[0-9]+}})
+; CHECK-DAG:    lw      $[[REG_D1_GOT:[0-9]+]], %got(d1)(${{[0-9]+}})
+; CHECK-DAG:    ldc1    $f[[REG_D2:[0-9]+]], 0($[[REG_D2_GOT]])
+; CHECK-DAG:    ldc1    $f[[REG_D1:[0-9]+]], 0($[[REG_D1_GOT]])
+; CHECK-DAG:    addiu   $[[REG_ZERO:[0-9]+]], $zero, 0
+; CHECK-DAG:    addiu   $[[REG_ONE:[0-9]+]], $zero, 1
+; CHECK:        c.ole.d  $f[[REG_D1]], $f[[REG_D2]]
+; CHECK:        movt  $[[REG_ZERO]], $[[REG_ONE]], $fcc0
+  %conv = zext i1 %cmp to i32
+  store i32 %conv, i32* @b1, align 4
+  ret void
+}
+
+; Function Attrs: nounwind
+define void @dge1()  {
+entry:
+  %0 = load double* @d1, align 8
+  %1 = load double* @d2, align 8
+  %cmp = fcmp oge double %0, %1
+; CHECK-LABEL:  dge1:
+; CHECK-DAG:    lw      $[[REG_D2_GOT:[0-9]+]], %got(d2)(${{[0-9]+}})
+; CHECK-DAG:    lw      $[[REG_D1_GOT:[0-9]+]], %got(d1)(${{[0-9]+}})
+; CHECK-DAG:    ldc1    $f[[REG_D2:[0-9]+]], 0($[[REG_D2_GOT]])
+; CHECK-DAG:    ldc1    $f[[REG_D1:[0-9]+]], 0($[[REG_D1_GOT]])
+; CHECK-DAG:    addiu   $[[REG_ZERO:[0-9]+]], $zero, 0
+; CHECK-DAG:    addiu   $[[REG_ONE:[0-9]+]], $zero, 1
+; CHECK:        c.ult.d  $f[[REG_D1]], $f[[REG_D2]]
+; CHECK:        movf  $[[REG_ZERO]], $[[REG_ONE]], $fcc0
+  %conv = zext i1 %cmp to i32
+  store i32 %conv, i32* @b1, align 4
+  ret void
+}
+
+