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ir/constant: Add support for 16-bit floating-point constants.
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@mewmew
mewmew committed Jan 7, 2017
1 parent 075cb05 commit e876622
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Showing 4 changed files with 87 additions and 34 deletions.
1 change: 1 addition & 0 deletions asm/internal/parser/parser_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -38,6 +38,7 @@ func TestParseString(t *testing.T) {
{path: "../testdata/ret.ll"},
{path: "../testdata/gep_forward_reference.ll"},
{path: "../testdata/const_struct.ll"},
{path: "../testdata/float16.ll"},
}
for _, g := range golden {
buf, err := ioutil.ReadFile(g.path)
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12 changes: 12 additions & 0 deletions asm/internal/testdata/float16.ll
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@@ -0,0 +1,12 @@
@a1 = global half 0xH3C00 ; 1.0
@a2 = global half 0xH4000 ; 2.0
@a3 = global half 0xHC000 ; -2.0
@a4 = global half 0xH7BFE ; 65472.0
@a5 = global half 0xH7BFF ; 65504.0
@a6 = global half 0xHFBFF ; -65504.0
@a7 = global half 0xH0000 ; 0.0
@a8 = global half 0xH8000 ; -0.0
@a9 = global half 0xH7C00 ; +inf
@a10 = global half 0xHFC00 ; -inf
@a11 = global half 0xH5B8F ; 241.875
@a12 = global half 0xH48C8 ; 9.5625
12 changes: 12 additions & 0 deletions asm/internal/testdata/float16.ll.golden
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@@ -0,0 +1,12 @@
@a1 = global half 1.0
@a2 = global half 2.0
@a3 = global half -2.0
@a4 = global half 65472.0
@a5 = global half 65504.0
@a6 = global half -65504.0
@a7 = global half 0.0
@a8 = global half -0.0
@a9 = global half 0xH7C00
@a10 = global half 0xHFC00
@a11 = global half 241.875
@a12 = global half 9.5625
96 changes: 62 additions & 34 deletions ir/constant/float.go
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Expand Up @@ -10,6 +10,7 @@ import (
"math/big"
"strings"

"github.com/llir/llvm/internal/floats"
"github.com/llir/llvm/ir/types"
)

Expand Down Expand Up @@ -41,65 +42,62 @@ func NewFloatFromString(s string, typ types.Type) *Float {
if !ok {
panic(fmt.Errorf("invalid floating-point constant type; expected *types.FloatType, got %T", typ))
}
c := &Float{X: &big.Float{}, Typ: t}
c := &Float{Typ: t}

// Parse floating-point literal based on its representation format.
//
// HexFP80Constant 0xK[0-9A-Fa-f]+ // 20 hex digits
// HexFP128Constant 0xL[0-9A-Fa-f]+ // 32 hex digits
// HexPPC128Constant 0xM[0-9A-Fa-f]+ // 32 hex digits
// HexHalfConstant 0xH[0-9A-Fa-f]+ // 4 hex digits
// HexFPConstant 0x[0-9A-Fa-f]+ // 16 hex digits
// FPConstant [-+]?[0-9]+[.][0-9]*([eE][-+]?[0-9]+)?
// Parse floating-point literal in hexadecimal format.
switch {
case strings.HasPrefix(s, "0xK"):
// HexFP80Constant 0xK[0-9A-Fa-f]+ // 20 hex digits

// TODO: Implement support for the 0xK floating-point representation format.
c.X = &big.Float{}
c.X.SetString("0.0") // TODO: Remove placehold zero value.
//panic(fmt.Errorf("support for floating-point constant 0xK representation not yet implemented; unable to parse floating-point constant %q", s))
s = s[len("0xK"):]
return c
case strings.HasPrefix(s, "0xL"):
// HexFP128Constant 0xL[0-9A-Fa-f]+ // 32 hex digits

// TODO: Implement support for the 0xL floating-point representation format.
c.X = &big.Float{}
c.X.SetString("0.0") // TODO: Remove placehold zero value.
//panic(fmt.Errorf("support for floating-point constant 0xL representation not yet implemented; unable to parse floating-point constant %q", s))
s = s[len("0xL"):]
return c
case strings.HasPrefix(s, "0xM"):
// HexPPC128Constant 0xM[0-9A-Fa-f]+ // 32 hex digits

// TODO: Implement support for the 0xM floating-point representation format.
c.X = &big.Float{}
c.X.SetString("0.0") // TODO: Remove placehold zero value.
//panic(fmt.Errorf("support for floating-point constant 0xM representation not yet implemented; unable to parse floating-point constant %q", s))
s = s[len("0xM"):]
return c
case strings.HasPrefix(s, "0xH"):
// TODO: Implement support for the 0xH floating-point representation format.
c.X.SetString("0.0") // TODO: Remove placehold zero value.
//panic(fmt.Errorf("support for floating-point constant 0xH representation not yet implemented; unable to parse floating-point constant %q", s))
s = s[len("0xH"):]
// HexHalfConstant 0xH[0-9A-Fa-f]+ // 4 hex digits

str := s[len("0xH"):]
x := floats.NewFloat16FromString(str)
c.X = big.NewFloat(x.Float64())
return c
case strings.HasPrefix(s, "0x"):
// HexFPConstant 0x[0-9A-Fa-f]+ // 16 hex digits

// TODO: Implement support for the 0x floating-point representation format.
c.X = &big.Float{}
c.X.SetString("0.0") // TODO: Remove placehold zero value.
//panic(fmt.Errorf("support for floating-point constant 0x representation not yet implemented; unable to parse floating-point constant %q", s))
s = s[len("0x"):]
default:
if _, ok := c.X.SetString(s); !ok {
panic(fmt.Errorf("unable to parse floating-point constant %q", s))
}
return c
}

// Verify that there was no precision loss.

// TODO: Re-enable precision loss validation. Disabled for now to allow for
// parsing of as part of sqlite.ll.
// Parse floating-point literal.
//
// %797 = fmul double %796, 1.000000e-01

//switch t.Kind {
//case types.FloatKindIEEE_32:
// if x, acc := c.X.Float32(); acc != big.Exact {
// panic(fmt.Errorf(`invalid floating-point constant %q for type %s; precision loss ("%g")`, s, typ, x))
// }
//case types.FloatKindIEEE_64:
// if x, acc := c.X.Float64(); acc != big.Exact {
// panic(fmt.Errorf(`invalid floating-point constant %q for type %s; precision loss ("%g")`, s, typ, x))
// }
//}
// FPConstant [-+]?[0-9]+[.][0-9]*([eE][-+]?[0-9]+)?
c.X = &big.Float{}
if _, ok := c.X.SetString(s); !ok {
panic(fmt.Errorf("unable to parse floating-point constant %q", s))
}
return c
}

Expand All @@ -110,10 +108,40 @@ func (c *Float) Type() types.Type {

// Ident returns the string representation of the constant.
func (c *Float) Ident() string {
// TODO: Handle NaN.

// Use hexadecimal representation for +Inf and -Inf.
if c.X.IsInf() {
switch c.Typ.Kind {
case types.FloatKindIEEE_16:
// TODO: Implement.
x, _ := c.X.Float64()
f16, _ := floats.NewFloat16FromFloat64(x)
return "0xH" + f16.String()
case types.FloatKindIEEE_32:
// TODO: Implement.
panic(fmt.Errorf("support for floating-point kind %v not yet implemented", c.Typ.Kind))
case types.FloatKindIEEE_64:
// TODO: Implement.
panic(fmt.Errorf("support for floating-point kind %v not yet implemented", c.Typ.Kind))
case types.FloatKindIEEE_128:
// TODO: Implement.
panic(fmt.Errorf("support for floating-point kind %v not yet implemented", c.Typ.Kind))
case types.FloatKindDoubleExtended_80:
// TODO: Implement.
panic(fmt.Errorf("support for floating-point kind %v not yet implemented", c.Typ.Kind))
case types.FloatKindDoubleDouble_128:
// TODO: Implement.
panic(fmt.Errorf("support for floating-point kind %v not yet implemented", c.Typ.Kind))
default:
panic(fmt.Errorf("support for floating-point kind %v not yet implemented", c.Typ.Kind))
}
}

// Insert decimal point if not present.
// 3e4 -> 3.0e4
// 42 -> 42.0
s := c.X.Text('g', -1)
s := c.X.Text('f', -1)
if !strings.ContainsRune(s, '.') {
if pos := strings.IndexByte(s, 'e'); pos != -1 {
s = s[:pos] + ".0" + s[pos:]
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