cmd/compile: add 32 bit float registers/variables on wasm

Before this change, wasm only used float variables with a size of 64 bit
and applied rounding to 32 bit precision where necessary. This change
adds proper 32 bit float variables.

Reduces the size of pkg/js_wasm by 254 bytes.

Change-Id: Ieabe846a8cb283d66def3cdf11e2523b3b31f345
Reviewed-on: https://go-review.googlesource.com/c/go/+/195117
Reviewed-by: Cherry Zhang <cherryyz@google.com>

1 files changed, 38 insertions, 25 deletions

diff --git a/src/cmd/compile/internal/wasm/ssa.go b/src/cmd/compile/internal/wasm/ssa.go
index 761a40227d..5b366eb08b 100644
--- a/src/cmd/compile/internal/wasm/ssa.go
+++ b/src/cmd/compile/internal/wasm/ssa.go
@@ -176,18 +176,12 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 	case ssa.OpWasmI64Store8, ssa.OpWasmI64Store16, ssa.OpWasmI64Store32, ssa.OpWasmI64Store, ssa.OpWasmF32Store, ssa.OpWasmF64Store:
 		getValue32(s, v.Args[0])
 		getValue64(s, v.Args[1])
-		if v.Op == ssa.OpWasmF32Store {
-			s.Prog(wasm.AF32DemoteF64)
-		}
 		p := s.Prog(v.Op.Asm())
 		p.To = obj.Addr{Type: obj.TYPE_CONST, Offset: v.AuxInt}
 
 	case ssa.OpStoreReg:
 		getReg(s, wasm.REG_SP)
 		getValue64(s, v.Args[0])
-		if v.Type.Etype == types.TFLOAT32 {
-			s.Prog(wasm.AF32DemoteF64)
-		}
 		p := s.Prog(storeOp(v.Type))
 		gc.AddrAuto(&p.To, v)
 
@@ -246,11 +240,6 @@ func ssaGenValueOnStack(s *gc.SSAGenState, v *ssa.Value, extend bool) {
 			panic("wasm: bad LoweredAddr")
 		}
 
-	case ssa.OpWasmLoweredRound32F:
-		getValue64(s, v.Args[0])
-		s.Prog(wasm.AF32DemoteF64)
-		s.Prog(wasm.AF64PromoteF32)
-
 	case ssa.OpWasmLoweredConvert:
 		getValue64(s, v.Args[0])
 
@@ -268,6 +257,9 @@ func ssaGenValueOnStack(s *gc.SSAGenState, v *ssa.Value, extend bool) {
 	case ssa.OpWasmI64Const:
 		i64Const(s, v.AuxInt)
 
+	case ssa.OpWasmF32Const:
+		f32Const(s, v.AuxFloat())
+
 	case ssa.OpWasmF64Const:
 		f64Const(s, v.AuxFloat())
 
@@ -275,9 +267,6 @@ func ssaGenValueOnStack(s *gc.SSAGenState, v *ssa.Value, extend bool) {
 		getValue32(s, v.Args[0])
 		p := s.Prog(v.Op.Asm())
 		p.From = obj.Addr{Type: obj.TYPE_CONST, Offset: v.AuxInt}
-		if v.Op == ssa.OpWasmF32Load {
-			s.Prog(wasm.AF64PromoteF32)
-		}
 
 	case ssa.OpWasmI64Eqz:
 		getValue64(s, v.Args[0])
@@ -286,7 +275,9 @@ func ssaGenValueOnStack(s *gc.SSAGenState, v *ssa.Value, extend bool) {
 			s.Prog(wasm.AI64ExtendI32U)
 		}
 
-	case ssa.OpWasmI64Eq, ssa.OpWasmI64Ne, ssa.OpWasmI64LtS, ssa.OpWasmI64LtU, ssa.OpWasmI64GtS, ssa.OpWasmI64GtU, ssa.OpWasmI64LeS, ssa.OpWasmI64LeU, ssa.OpWasmI64GeS, ssa.OpWasmI64GeU, ssa.OpWasmF64Eq, ssa.OpWasmF64Ne, ssa.OpWasmF64Lt, ssa.OpWasmF64Gt, ssa.OpWasmF64Le, ssa.OpWasmF64Ge:
+	case ssa.OpWasmI64Eq, ssa.OpWasmI64Ne, ssa.OpWasmI64LtS, ssa.OpWasmI64LtU, ssa.OpWasmI64GtS, ssa.OpWasmI64GtU, ssa.OpWasmI64LeS, ssa.OpWasmI64LeU, ssa.OpWasmI64GeS, ssa.OpWasmI64GeU,
+		ssa.OpWasmF32Eq, ssa.OpWasmF32Ne, ssa.OpWasmF32Lt, ssa.OpWasmF32Gt, ssa.OpWasmF32Le, ssa.OpWasmF32Ge,
+		ssa.OpWasmF64Eq, ssa.OpWasmF64Ne, ssa.OpWasmF64Lt, ssa.OpWasmF64Gt, ssa.OpWasmF64Le, ssa.OpWasmF64Ge:
 		getValue64(s, v.Args[0])
 		getValue64(s, v.Args[1])
 		s.Prog(v.Op.Asm())
@@ -294,7 +285,9 @@ func ssaGenValueOnStack(s *gc.SSAGenState, v *ssa.Value, extend bool) {
 			s.Prog(wasm.AI64ExtendI32U)
 		}
 
-	case ssa.OpWasmI64Add, ssa.OpWasmI64Sub, ssa.OpWasmI64Mul, ssa.OpWasmI64DivU, ssa.OpWasmI64RemS, ssa.OpWasmI64RemU, ssa.OpWasmI64And, ssa.OpWasmI64Or, ssa.OpWasmI64Xor, ssa.OpWasmI64Shl, ssa.OpWasmI64ShrS, ssa.OpWasmI64ShrU, ssa.OpWasmF64Add, ssa.OpWasmF64Sub, ssa.OpWasmF64Mul, ssa.OpWasmF64Div, ssa.OpWasmF64Copysign, ssa.OpWasmI64Rotl:
+	case ssa.OpWasmI64Add, ssa.OpWasmI64Sub, ssa.OpWasmI64Mul, ssa.OpWasmI64DivU, ssa.OpWasmI64RemS, ssa.OpWasmI64RemU, ssa.OpWasmI64And, ssa.OpWasmI64Or, ssa.OpWasmI64Xor, ssa.OpWasmI64Shl, ssa.OpWasmI64ShrS, ssa.OpWasmI64ShrU, ssa.OpWasmI64Rotl,
+		ssa.OpWasmF32Add, ssa.OpWasmF32Sub, ssa.OpWasmF32Mul, ssa.OpWasmF32Div, ssa.OpWasmF32Copysign,
+		ssa.OpWasmF64Add, ssa.OpWasmF64Sub, ssa.OpWasmF64Mul, ssa.OpWasmF64Div, ssa.OpWasmF64Copysign:
 		getValue64(s, v.Args[0])
 		getValue64(s, v.Args[1])
 		s.Prog(v.Op.Asm())
@@ -316,37 +309,50 @@ func ssaGenValueOnStack(s *gc.SSAGenState, v *ssa.Value, extend bool) {
 		}
 		s.Prog(wasm.AI64DivS)
 
-	case ssa.OpWasmI64TruncSatF64S:
+	case ssa.OpWasmI64TruncSatF32S, ssa.OpWasmI64TruncSatF64S:
 		getValue64(s, v.Args[0])
 		if objabi.GOWASM.SatConv {
 			s.Prog(v.Op.Asm())
 		} else {
+			if v.Op == ssa.OpWasmI64TruncSatF32S {
+				s.Prog(wasm.AF64PromoteF32)
+			}
 			p := s.Prog(wasm.ACall)
 			p.To = obj.Addr{Type: obj.TYPE_MEM, Name: obj.NAME_EXTERN, Sym: gc.WasmTruncS}
 		}
 
-	case ssa.OpWasmI64TruncSatF64U:
+	case ssa.OpWasmI64TruncSatF32U, ssa.OpWasmI64TruncSatF64U:
 		getValue64(s, v.Args[0])
 		if objabi.GOWASM.SatConv {
 			s.Prog(v.Op.Asm())
 		} else {
+			if v.Op == ssa.OpWasmI64TruncSatF32U {
+				s.Prog(wasm.AF64PromoteF32)
+			}
 			p := s.Prog(wasm.ACall)
 			p.To = obj.Addr{Type: obj.TYPE_MEM, Name: obj.NAME_EXTERN, Sym: gc.WasmTruncU}
 		}
 
-	case
-		ssa.OpWasmF64Neg, ssa.OpWasmF64ConvertI64S, ssa.OpWasmF64ConvertI64U,
+	case ssa.OpWasmF32DemoteF64:
+		getValue64(s, v.Args[0])
+		s.Prog(v.Op.Asm())
+
+	case ssa.OpWasmF64PromoteF32:
+		getValue64(s, v.Args[0])
+		s.Prog(v.Op.Asm())
+
+	case ssa.OpWasmF32ConvertI64S, ssa.OpWasmF32ConvertI64U,
+		ssa.OpWasmF64ConvertI64S, ssa.OpWasmF64ConvertI64U,
 		ssa.OpWasmI64Extend8S, ssa.OpWasmI64Extend16S, ssa.OpWasmI64Extend32S,
-		ssa.OpWasmF64Sqrt, ssa.OpWasmF64Trunc, ssa.OpWasmF64Ceil, ssa.OpWasmF64Floor, ssa.OpWasmF64Nearest, ssa.OpWasmF64Abs, ssa.OpWasmI64Ctz, ssa.OpWasmI64Clz, ssa.OpWasmI64Popcnt:
+		ssa.OpWasmF32Neg, ssa.OpWasmF32Sqrt, ssa.OpWasmF32Trunc, ssa.OpWasmF32Ceil, ssa.OpWasmF32Floor, ssa.OpWasmF32Nearest, ssa.OpWasmF32Abs,
+		ssa.OpWasmF64Neg, ssa.OpWasmF64Sqrt, ssa.OpWasmF64Trunc, ssa.OpWasmF64Ceil, ssa.OpWasmF64Floor, ssa.OpWasmF64Nearest, ssa.OpWasmF64Abs,
+		ssa.OpWasmI64Ctz, ssa.OpWasmI64Clz, ssa.OpWasmI64Popcnt:
 		getValue64(s, v.Args[0])
 		s.Prog(v.Op.Asm())
 
 	case ssa.OpLoadReg:
 		p := s.Prog(loadOp(v.Type))
 		gc.AddrAuto(&p.From, v.Args[0])
-		if v.Type.Etype == types.TFLOAT32 {
-			s.Prog(wasm.AF64PromoteF32)
-		}
 
 	case ssa.OpCopy:
 		getValue64(s, v.Args[0])
@@ -359,7 +365,9 @@ func ssaGenValueOnStack(s *gc.SSAGenState, v *ssa.Value, extend bool) {
 
 func isCmp(v *ssa.Value) bool {
 	switch v.Op {
-	case ssa.OpWasmI64Eqz, ssa.OpWasmI64Eq, ssa.OpWasmI64Ne, ssa.OpWasmI64LtS, ssa.OpWasmI64LtU, ssa.OpWasmI64GtS, ssa.OpWasmI64GtU, ssa.OpWasmI64LeS, ssa.OpWasmI64LeU, ssa.OpWasmI64GeS, ssa.OpWasmI64GeU, ssa.OpWasmF64Eq, ssa.OpWasmF64Ne, ssa.OpWasmF64Lt, ssa.OpWasmF64Gt, ssa.OpWasmF64Le, ssa.OpWasmF64Ge:
+	case ssa.OpWasmI64Eqz, ssa.OpWasmI64Eq, ssa.OpWasmI64Ne, ssa.OpWasmI64LtS, ssa.OpWasmI64LtU, ssa.OpWasmI64GtS, ssa.OpWasmI64GtU, ssa.OpWasmI64LeS, ssa.OpWasmI64LeU, ssa.OpWasmI64GeS, ssa.OpWasmI64GeU,
+		ssa.OpWasmF32Eq, ssa.OpWasmF32Ne, ssa.OpWasmF32Lt, ssa.OpWasmF32Gt, ssa.OpWasmF32Le, ssa.OpWasmF32Ge,
+		ssa.OpWasmF64Eq, ssa.OpWasmF64Ne, ssa.OpWasmF64Lt, ssa.OpWasmF64Gt, ssa.OpWasmF64Le, ssa.OpWasmF64Ge:
 		return true
 	default:
 		return false
@@ -407,6 +415,11 @@ func i64Const(s *gc.SSAGenState, val int64) {
 	p.From = obj.Addr{Type: obj.TYPE_CONST, Offset: val}
 }
 
+func f32Const(s *gc.SSAGenState, val float64) {
+	p := s.Prog(wasm.AF32Const)
+	p.From = obj.Addr{Type: obj.TYPE_FCONST, Val: val}
+}
+
 func f64Const(s *gc.SSAGenState, val float64) {
 	p := s.Prog(wasm.AF64Const)
 	p.From = obj.Addr{Type: obj.TYPE_FCONST, Val: val}