[MIPS][float] Fixed SingleFloat codegen on N32/N64 targets

Author: Tazdevil971

llvm/lib/Target/Mips/MipsCallingConv.td

@@ -196,7 +196,8 @@ def RetCC_MipsN : CallingConv<[
   //
   // f128 should only occur for the N64 ABI where long double is 128-bit. On
   // N32, long double is equivalent to double.
-  CCIfType<[i64], CCIfOrigArgWasF128<CCDelegateTo<RetCC_F128>>>,
+  CCIfSubtargetNot<"isSingleFloat()",
+      CCIfType<[i64], CCIfOrigArgWasF128<CCDelegateTo<RetCC_F128>>>>,
 
   // Aggregate returns are positioned at the lowest address in the slot for
   // both little and big-endian targets. When passing in registers, this
@@ -333,9 +334,10 @@ def CC_Mips_FixedArg : CallingConv<[
   //
   // f128 should only occur for the N64 ABI where long double is 128-bit. On
   // N32, long double is equivalent to double.
-  CCIfType<[i64],
-      CCIfSubtargetNot<"useSoftFloat()",
-          CCIfOrigArgWasF128<CCBitConvertToType<f64>>>>,
+  CCIfType<[i64], 
+      CCIfSubtargetNot<"isSingleFloat()",
+          CCIfSubtargetNot<"useSoftFloat()", 
+              CCIfOrigArgWasF128<CCBitConvertToType<f64>>>>>,
 
   CCIfCC<"CallingConv::Fast", CCDelegateTo<CC_Mips_FastCC>>,
 
@@ -359,8 +361,8 @@ def CC_Mips : CallingConv<[
 // Callee-saved register lists.
 //===----------------------------------------------------------------------===//
 
-def CSR_SingleFloatOnly : CalleeSavedRegs<(add (sequence "F%u", 31, 20), RA, FP,
-                                               (sequence "S%u", 7, 0))>;
+def CSR_O32_SingleFloat : CalleeSavedRegs<(add(sequence "F%u", 31, 20), RA, FP,
+                              (sequence "S%u", 7, 0))>;
 
 def CSR_O32_FPXX : CalleeSavedRegs<(add (sequence "D%u", 15, 10), RA, FP,
                                         (sequence "S%u", 7, 0))> {
@@ -374,13 +376,19 @@ def CSR_O32_FP64 :
   CalleeSavedRegs<(add (decimate (sequence "D%u_64", 30, 20), 2), RA, FP,
                        (sequence "S%u", 7, 0))>;
 
-def CSR_N32 : CalleeSavedRegs<(add D20_64, D22_64, D24_64, D26_64, D28_64,
-                                   D30_64, RA_64, FP_64, GP_64,
-                                   (sequence "S%u_64", 7, 0))>;
+def CSR_N32 : CalleeSavedRegs<(add(decimate(sequence "D%u_64", 30, 20), 2),
+                  RA_64, FP_64, GP_64, (sequence "S%u_64", 7, 0))>;
+
+def CSR_N32_SingleFloat
+    : CalleeSavedRegs<(add(decimate(sequence "F%u", 30, 20), 2), RA_64, FP_64,
+          GP_64, (sequence "S%u_64", 7, 0))>;
 
 def CSR_N64 : CalleeSavedRegs<(add (sequence "D%u_64", 31, 24), RA_64, FP_64,
                                    GP_64, (sequence "S%u_64", 7, 0))>;
 
+def CSR_N64_SingleFloat : CalleeSavedRegs<(add(sequence "F%u", 31, 24), RA_64,
+                              FP_64, GP_64, (sequence "S%u_64", 7, 0))>;
+
 def CSR_Mips16RetHelper :
   CalleeSavedRegs<(add V0, V1, FP,
                    (sequence "A%u", 3, 0), (sequence "S%u", 7, 0),

llvm/lib/Target/Mips/MipsISelLowering.cpp

@@ -4295,10 +4295,16 @@ parseRegForInlineAsmConstraint(StringRef C, MVT VT) const {
     return std::make_pair(0U, nullptr);
 
   if (Prefix == "$f") { // Parse $f0-$f31.
-    // If the size of FP registers is 64-bit or Reg is an even number, select
-    // the 64-bit register class. Otherwise, select the 32-bit register class.
-    if (VT == MVT::Other)
-      VT = (Subtarget.isFP64bit() || !(Reg % 2)) ? MVT::f64 : MVT::f32;
+    // If the targets is single float only, always select 32-bit registers,
+    // otherwise if the size of FP registers is 64-bit or Reg is an even number,
+    // select the 64-bit register class. Otherwise, select the 32-bit register
+    // class.
+    if (VT == MVT::Other) {
+      if (Subtarget.isSingleFloat())
+        VT = MVT::f32;
+      else
+        VT = (Subtarget.isFP64bit() || !(Reg % 2)) ? MVT::f64 : MVT::f32;
+    }
 
     RC = getRegClassFor(VT);
 
@@ -4338,10 +4344,12 @@ MipsTargetLowering::getRegForInlineAsmConstraint(const TargetRegisterInfo *TRI,
           return std::make_pair(0U, &Mips::CPU16RegsRegClass);
         return std::make_pair(0U, &Mips::GPR32RegClass);
       }
-      if ((VT == MVT::i64 || (VT == MVT::f64 && Subtarget.useSoftFloat())) &&
+      if ((VT == MVT::i64 || (VT == MVT::f64 && Subtarget.useSoftFloat()) ||
+           (VT == MVT::f64 && Subtarget.isSingleFloat())) &&
           !Subtarget.isGP64bit())
         return std::make_pair(0U, &Mips::GPR32RegClass);
-      if ((VT == MVT::i64 || (VT == MVT::f64 && Subtarget.useSoftFloat())) &&
+      if ((VT == MVT::i64 || (VT == MVT::f64 && Subtarget.useSoftFloat()) ||
+           (VT == MVT::f64 && Subtarget.isSingleFloat())) &&
           Subtarget.isGP64bit())
         return std::make_pair(0U, &Mips::GPR64RegClass);
       // This will generate an error message

llvm/lib/Target/Mips/MipsRegisterInfo.cpp

@@ -102,14 +102,25 @@ MipsRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
                                      : CSR_Interrupt_32_SaveList;
   }
 
-  if (Subtarget.isSingleFloat())
-    return CSR_SingleFloatOnly_SaveList;
+  // N64 ABI
+  if (Subtarget.isABI_N64()) {
+    if (Subtarget.isSingleFloat())
+      return CSR_N64_SingleFloat_SaveList;
 
-  if (Subtarget.isABI_N64())
     return CSR_N64_SaveList;
+  }
+
+  // N32 ABI
+  if (Subtarget.isABI_N32()) {
+    if (Subtarget.isSingleFloat())
+      return CSR_N32_SingleFloat_SaveList;
 
-  if (Subtarget.isABI_N32())
     return CSR_N32_SaveList;
+  }
+
+  // O32 ABI
+  if (Subtarget.isSingleFloat())
+    return CSR_O32_SingleFloat_SaveList;
 
   if (Subtarget.isFP64bit())
     return CSR_O32_FP64_SaveList;
@@ -124,14 +135,25 @@ const uint32_t *
 MipsRegisterInfo::getCallPreservedMask(const MachineFunction &MF,
                                        CallingConv::ID) const {
   const MipsSubtarget &Subtarget = MF.getSubtarget<MipsSubtarget>();
-  if (Subtarget.isSingleFloat())
-    return CSR_SingleFloatOnly_RegMask;
+  // N64 ABI
+  if (Subtarget.isABI_N64()) {
+    if (Subtarget.isSingleFloat())
+      return CSR_N64_SingleFloat_RegMask;
 
-  if (Subtarget.isABI_N64())
     return CSR_N64_RegMask;
+  }
+
+  // N32 ABI
+  if (Subtarget.isABI_N32()) {
+    if (Subtarget.isSingleFloat())
+      return CSR_N32_SingleFloat_RegMask;
 
-  if (Subtarget.isABI_N32())
     return CSR_N32_RegMask;
+  }
+
+  // O32 ABI
+  if (Subtarget.isSingleFloat())
+    return CSR_O32_SingleFloat_RegMask;
 
   if (Subtarget.isFP64bit())
     return CSR_O32_FP64_RegMask;

llvm/lib/Target/Mips/MipsSEISelLowering.cpp

@@ -28,6 +28,7 @@
 #include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/CodeGen/SelectionDAGNodes.h"
 #include "llvm/CodeGen/TargetInstrInfo.h"
+#include "llvm/CodeGen/TargetLowering.h"
 #include "llvm/CodeGen/TargetSubtargetInfo.h"
 #include "llvm/CodeGen/ValueTypes.h"
 #include "llvm/CodeGenTypes/MachineValueType.h"
@@ -211,6 +212,20 @@ MipsSETargetLowering::MipsSETargetLowering(const MipsTargetMachine &TM,
     }
   }
 
+  // Targets with 64bits integer registers, but no 64bit floating point register
+  // do not support conversion between them
+  if (Subtarget.isGP64bit() && Subtarget.isSingleFloat() &&
+      !Subtarget.useSoftFloat()) {
+    setOperationAction(ISD::FP_TO_SINT, MVT::i64, Expand);
+    setOperationAction(ISD::FP_TO_UINT, MVT::i64, Expand);
+    setOperationAction(ISD::STRICT_FP_TO_SINT, MVT::i64, Expand);
+    setOperationAction(ISD::STRICT_FP_TO_UINT, MVT::i64, Expand);
+    setOperationAction(ISD::SINT_TO_FP, MVT::i64, Expand);
+    setOperationAction(ISD::UINT_TO_FP, MVT::i64, Expand);
+    setOperationAction(ISD::STRICT_SINT_TO_FP, MVT::i64, Expand);
+    setOperationAction(ISD::STRICT_UINT_TO_FP, MVT::i64, Expand);
+  }
+
   setOperationAction(ISD::SMUL_LOHI,          MVT::i32, Custom);
   setOperationAction(ISD::UMUL_LOHI,          MVT::i32, Custom);
   setOperationAction(ISD::MULHS,              MVT::i32, Custom);

llvm/test/CodeGen/Mips/cconv/arguments-hard-single-float-varargs.ll

@@ -0,0 +1,148 @@
+; RUN: llc -mtriple=mips -relocation-model=static -mattr=single-float < %s \
+; RUN:   | FileCheck --check-prefixes=ALL,SYM32,O32 %s
+; RUN: llc -mtriple=mipsel -relocation-model=static -mattr=single-float < %s \
+; RUN:   | FileCheck --check-prefixes=ALL,SYM32,O32 %s
+
+; RUN: llc -mtriple=mips64 -relocation-model=static -target-abi n32 -mattr=single-float < %s \
+; RUN:   | FileCheck --check-prefixes=ALL,SYM32,N32,NEW,NEWBE %s
+; RUN: llc -mtriple=mips64el -relocation-model=static -target-abi n32 -mattr=single-float < %s \
+; RUN:   | FileCheck --check-prefixes=ALL,SYM32,N32,NEW,NEWLE %s
+
+; RUN: llc -mtriple=mips64 -relocation-model=static -target-abi n64 -mattr=single-float < %s \
+; RUN:   | FileCheck --check-prefixes=ALL,SYM64,N64,NEW,NEWBE %s
+; RUN: llc -mtriple=mips64el -relocation-model=static -target-abi n64 -mattr=single-float < %s \
+; RUN:   | FileCheck --check-prefixes=ALL,SYM64,N64,NEW,NEWLE %s
+
+@floats = global [11 x float] zeroinitializer
+@doubles = global [11 x double] zeroinitializer
+
+define void @double_args(double %a, ...)
+                         nounwind {
+entry:
+        %0 = getelementptr [11 x double], ptr @doubles, i32 0, i32 1
+        store volatile double %a, ptr %0
+
+        %ap = alloca ptr
+        call void @llvm.va_start(ptr %ap)
+        %b = va_arg ptr %ap, double
+        %1 = getelementptr [11 x double], ptr @doubles, i32 0, i32 2
+        store volatile double %b, ptr %1
+        call void @llvm.va_end(ptr %ap)
+        ret void
+}
+
+; ALL-LABEL: double_args:
+; We won't test the way the global address is calculated in this test. This is
+; just to get the register number for the other checks.
+; SYM32-DAG:         addiu [[R2:\$[0-9]+]], ${{[0-9]+}}, %lo(doubles)
+; SYM64-DAG:         daddiu [[R2:\$[0-9]+]], ${{[0-9]+}}, %lo(doubles)
+
+; O32 forbids using floating point registers for the non-variable portion.
+; N32/N64 allow it.
+; O32-DAG:           sw $4, 8([[R2]])
+; O32-DAG:           sw $5, 12([[R2]])
+; NEW-DAG:           sd $4, 8([[R2]])
+
+; The varargs portion is dumped to stack
+; O32-DAG:           sw $6, 16($sp)
+; O32-DAG:           sw $7, 20($sp)
+; NEW-DAG:           sd $5, 8($sp)
+; NEW-DAG:           sd $6, 16($sp)
+; NEW-DAG:           sd $7, 24($sp)
+; NEW-DAG:           sd $8, 32($sp)
+; NEW-DAG:           sd $9, 40($sp)
+; NEW-DAG:           sd $10, 48($sp)
+; NEW-DAG:           sd $11, 56($sp)
+
+; Get the varargs pointer
+; O32 has 4 bytes padding, 4 bytes for the varargs pointer, and 8 bytes reserved
+; for arguments 1 and 2.
+; N32/N64 has 8 bytes for the varargs pointer, and no reserved area.
+; O32-DAG:           addiu [[VAPTR:\$[0-9]+]], $sp, 16
+; O32-DAG:           sw [[VAPTR]], 4($sp)
+; N32-DAG:           addiu [[VAPTR:\$[0-9]+]], $sp, 8
+; N32-DAG:           sw [[VAPTR]], 4($sp)
+; N64-DAG:           daddiu [[VAPTR:\$[0-9]+]], $sp, 8
+; N64-DAG:           sd [[VAPTR]], 0($sp)
+
+; Increment the pointer then get the varargs arg
+; LLVM will rebind the load to the stack pointer instead of the varargs pointer
+; during lowering. This is fine and doesn't change the behaviour.
+; O32-DAG:           addiu [[VAPTR]], [[VAPTR]], 8
+; N32-DAG:           addiu [[VAPTR]], [[VAPTR]], 8
+; N64-DAG:           daddiu [[VAPTR]], [[VAPTR]], 8
+; O32-DAG:           lw	[[R3:\$[0-9]+]], 16($sp)
+; O32-DAG:           lw	[[R4:\$[0-9]+]], 20($sp)
+; O32-DAG:           sw [[R3]], 16([[R2]])
+; O32-DAG:           sw [[R4]], 20([[R2]])
+; NEW-DAG:           ld [[R3:\$[0-9]+]], 8($sp)
+; NEW-DAG:           sd [[R3]], 16([[R2]])
+
+define void @float_args(float %a, ...) nounwind {
+entry:
+        %0 = getelementptr [11 x float], ptr @floats, i32 0, i32 1
+        store volatile float %a, ptr %0
+
+        %ap = alloca ptr
+        call void @llvm.va_start(ptr %ap)
+        %b = va_arg ptr %ap, float
+        %1 = getelementptr [11 x float], ptr @floats, i32 0, i32 2
+        store volatile float %b, ptr %1
+        call void @llvm.va_end(ptr %ap)
+        ret void
+}
+
+; ALL-LABEL: float_args:
+; We won't test the way the global address is calculated in this test. This is
+; just to get the register number for the other checks.
+; SYM32-DAG:         addiu [[R2:\$[0-9]+]], ${{[0-9]+}}, %lo(floats)
+; SYM64-DAG:         daddiu [[R2:\$[0-9]+]], ${{[0-9]+}}, %lo(floats)
+
+; The first four arguments are the same in O32/N32/N64.
+; The non-variable portion should be unaffected.
+; O32-DAG:           mtc1 $4, $f0
+; O32-DAG:           swc1 $f0, 4([[R2]])
+; NEW-DAG:           swc1 $f12, 4([[R2]])
+
+; The varargs portion is dumped to stack
+; O32-DAG:           sw $5, 12($sp)
+; O32-DAG:           sw $6, 16($sp)
+; O32-DAG:           sw $7, 20($sp)
+; NEW-DAG:           sd $5, 8($sp)
+; NEW-DAG:           sd $6, 16($sp)
+; NEW-DAG:           sd $7, 24($sp)
+; NEW-DAG:           sd $8, 32($sp)
+; NEW-DAG:           sd $9, 40($sp)
+; NEW-DAG:           sd $10, 48($sp)
+; NEW-DAG:           sd $11, 56($sp)
+
+; Get the varargs pointer
+; O32 has 4 bytes padding, 4 bytes for the varargs pointer, and should have 8
+; bytes reserved for arguments 1 and 2 (the first float arg) but as discussed in
+; arguments-float.ll, GCC doesn't agree with MD00305 and treats floats as 4
+; bytes so we only have 12 bytes total.
+; N32/N64 has 8 bytes for the varargs pointer, and no reserved area.
+; O32-DAG:           addiu [[VAPTR:\$[0-9]+]], $sp, 12
+; O32-DAG:           sw [[VAPTR]], 4($sp)
+; N32-DAG:           addiu [[VAPTR:\$[0-9]+]], $sp, 8
+; N32-DAG:           sw [[VAPTR]], 4($sp)
+; N64-DAG:           daddiu [[VAPTR:\$[0-9]+]], $sp, 8
+; N64-DAG:           sd [[VAPTR]], 0($sp)
+
+; Increment the pointer then get the varargs arg
+; LLVM will rebind the load to the stack pointer instead of the varargs pointer
+; during lowering. This is fine and doesn't change the behaviour.
+; Also, in big-endian mode the offset must be increased by 4 to retrieve the
+; correct half of the argument slot.
+;
+; O32-DAG:           addiu [[VAPTR]], [[VAPTR]], 4
+; N32-DAG:           addiu [[VAPTR]], [[VAPTR]], 8
+; N64-DAG:           daddiu [[VAPTR]], [[VAPTR]], 8
+; O32-DAG:           lwc1 [[FTMP1:\$f[0-9]+]], 12($sp)
+; NEWLE-DAG:         lwc1 [[FTMP1:\$f[0-9]+]], 8($sp)
+; NEWBE-DAG:         lwc1 [[FTMP1:\$f[0-9]+]], 12($sp)
+; ALL-DAG:           swc1 [[FTMP1]], 8([[R2]])
+
+declare void @llvm.va_start(ptr)
+declare void @llvm.va_copy(ptr, ptr)
+declare void @llvm.va_end(ptr)