build: mov deduction for booleans (#341)

Updates #336

tests/fixedbugs/issue336/asm.go

@@ -0,0 +1,38 @@
+//go:build ignore
+// +build ignore
+
+package main
+
+import (
+	"fmt"
+
+	. "github.com/mmcloughlin/avo/build"
+	. "github.com/mmcloughlin/avo/operand"
+	. "github.com/mmcloughlin/avo/reg"
+)
+
+func main() {
+	variants := []struct {
+		Size     int
+		Register func() GPVirtual
+		XOR      func(Op, Op)
+	}{
+		{8, GP8L, XORB},
+		{16, GP16, XORW},
+		{32, GP32, XORL},
+		{64, GP64, XORQ},
+	}
+
+	for _, v := range variants {
+		name := fmt.Sprintf("Not%d", v.Size)
+		TEXT(name, NOSPLIT, "func(x bool) bool")
+		Doc(fmt.Sprintf("%s returns the boolean negation of x using a %d-bit intermediate.", name, v.Size))
+		x := v.Register()
+		Load(Param("x"), x)
+		v.XOR(U8(1), x)
+		Store(x.As8L(), ReturnIndex(0))
+		RET()
+	}
+
+	Generate()
+}

tests/fixedbugs/issue336/doc.go

@@ -0,0 +1,4 @@
+// Package issue336 tests boolean arguments and return values.
+//
+// Issue #336 pointed out that move deduction for boolean types was not present.
+package issue336

tests/fixedbugs/issue336/issue336.s

@@ -0,0 +1,31 @@
+// Code generated by command: go run asm.go -out issue336.s -stubs stub.go. DO NOT EDIT.
+
+#include "textflag.h"
+
+// func Not8(x bool) bool
+TEXT ·Not8(SB), NOSPLIT, $0-9
+	MOVB x+0(FP), AL
+	XORB $0x01, AL
+	MOVB AL, ret+8(FP)
+	RET
+
+// func Not16(x bool) bool
+TEXT ·Not16(SB), NOSPLIT, $0-9
+	MOVBWZX x+0(FP), AX
+	XORW    $0x01, AX
+	MOVB    AL, ret+8(FP)
+	RET
+
+// func Not32(x bool) bool
+TEXT ·Not32(SB), NOSPLIT, $0-9
+	MOVBLZX x+0(FP), AX
+	XORL    $0x01, AX
+	MOVB    AL, ret+8(FP)
+	RET
+
+// func Not64(x bool) bool
+TEXT ·Not64(SB), NOSPLIT, $0-9
+	MOVBQZX x+0(FP), AX
+	XORQ    $0x01, AX
+	MOVB    AL, ret+8(FP)
+	RET

tests/fixedbugs/issue336/issue336_test.go

@@ -0,0 +1,16 @@
+package issue336
+
+import "testing"
+
+//go:generate go run asm.go -out issue336.s -stubs stub.go
+
+func TestNot(t *testing.T) {
+	nots := []func(bool) bool{Not8, Not16, Not32, Not64}
+	for _, not := range nots {
+		for _, x := range []bool{true, false} {
+			if not(x) != !x {
+				t.Fail()
+			}
+		}
+	}
+}

tests/fixedbugs/issue336/stub.go

@@ -0,0 +1,15 @@
+// Code generated by command: go run asm.go -out issue336.s -stubs stub.go. DO NOT EDIT.
+
+package issue336
+
+// Not8 returns the boolean negation of x using a 8-bit intermediate.
+func Not8(x bool) bool
+
+// Not16 returns the boolean negation of x using a 16-bit intermediate.
+func Not16(x bool) bool
+
+// Not32 returns the boolean negation of x using a 32-bit intermediate.
+func Not32(x bool) bool
+
+// Not64 returns the boolean negation of x using a 64-bit intermediate.
+func Not64(x bool) bool