cmd/compile: add tests for logical simplification rewrite rules

Increases coverage of generic.rules from 72% to 84%.

Change-Id: I1b139aeeb6410d025d49cbe4e4601f6f935ce1e5
Reviewed-on: https://go-review.googlesource.com/23490
Reviewed-by: Todd Neal <todd@tneal.org>

1 files changed, 289 insertions, 0 deletions

diff --git a/src/cmd/compile/internal/gc/logic_test.go b/src/cmd/compile/internal/gc/logic_test.go
new file mode 100644
index 0000000000..78d2dd2fa8
--- /dev/null
+++ b/src/cmd/compile/internal/gc/logic_test.go
@@ -0,0 +1,289 @@
+package gc
+
+import "testing"
+
+// Tests to make sure logic simplification rules are correct.
+
+func TestLogic64(t *testing.T) {
+	// test values to determine function equality
+	values := [...]int64{-1 << 63, 1<<63 - 1, -4, -3, -2, -1, 0, 1, 2, 3, 4}
+
+	// golden functions we use repeatedly
+	zero := func(x int64) int64 { return 0 }
+	id := func(x int64) int64 { return x }
+	or := func(x, y int64) int64 { return x | y }
+	and := func(x, y int64) int64 { return x & y }
+	y := func(x, y int64) int64 { return y }
+
+	for _, test := range [...]struct {
+		name   string
+		f      func(int64) int64
+		golden func(int64) int64
+	}{
+		{"x|x", func(x int64) int64 { return x | x }, id},
+		{"x|0", func(x int64) int64 { return x | 0 }, id},
+		{"x|-1", func(x int64) int64 { return x | -1 }, func(x int64) int64 { return -1 }},
+		{"x&x", func(x int64) int64 { return x & x }, id},
+		{"x&0", func(x int64) int64 { return x & 0 }, zero},
+		{"x&-1", func(x int64) int64 { return x & -1 }, id},
+		{"x^x", func(x int64) int64 { return x ^ x }, zero},
+		{"x^0", func(x int64) int64 { return x ^ 0 }, id},
+		{"x^-1", func(x int64) int64 { return x ^ -1 }, func(x int64) int64 { return ^x }},
+		{"x+0", func(x int64) int64 { return x + 0 }, id},
+		{"x-x", func(x int64) int64 { return x - x }, zero},
+		{"x*0", func(x int64) int64 { return x * 0 }, zero},
+		{"^^x", func(x int64) int64 { return ^^x }, id},
+	} {
+		for _, v := range values {
+			got := test.f(v)
+			want := test.golden(v)
+			if want != got {
+				t.Errorf("[%s](%d)=%d, want %d", test.name, v, got, want)
+			}
+		}
+	}
+	for _, test := range [...]struct {
+		name   string
+		f      func(int64, int64) int64
+		golden func(int64, int64) int64
+	}{
+		{"x|(x|y)", func(x, y int64) int64 { return x | (x | y) }, or},
+		{"x|(y|x)", func(x, y int64) int64 { return x | (y | x) }, or},
+		{"(x|y)|x", func(x, y int64) int64 { return (x | y) | x }, or},
+		{"(y|x)|x", func(x, y int64) int64 { return (y | x) | x }, or},
+		{"x&(x&y)", func(x, y int64) int64 { return x & (x & y) }, and},
+		{"x&(y&x)", func(x, y int64) int64 { return x & (y & x) }, and},
+		{"(x&y)&x", func(x, y int64) int64 { return (x & y) & x }, and},
+		{"(y&x)&x", func(x, y int64) int64 { return (y & x) & x }, and},
+		{"x^(x^y)", func(x, y int64) int64 { return x ^ (x ^ y) }, y},
+		{"x^(y^x)", func(x, y int64) int64 { return x ^ (y ^ x) }, y},
+		{"(x^y)^x", func(x, y int64) int64 { return (x ^ y) ^ x }, y},
+		{"(y^x)^x", func(x, y int64) int64 { return (y ^ x) ^ x }, y},
+		{"-(y-x)", func(x, y int64) int64 { return -(y - x) }, func(x, y int64) int64 { return x - y }},
+		{"(x+y)-x", func(x, y int64) int64 { return (x + y) - x }, y},
+		{"(y+x)-x", func(x, y int64) int64 { return (y + x) - x }, y},
+	} {
+		for _, v := range values {
+			for _, w := range values {
+				got := test.f(v, w)
+				want := test.golden(v, w)
+				if want != got {
+					t.Errorf("[%s](%d,%d)=%d, want %d", test.name, v, w, got, want)
+				}
+			}
+		}
+	}
+}
+
+func TestLogic32(t *testing.T) {
+	// test values to determine function equality
+	values := [...]int32{-1 << 31, 1<<31 - 1, -4, -3, -2, -1, 0, 1, 2, 3, 4}
+
+	// golden functions we use repeatedly
+	zero := func(x int32) int32 { return 0 }
+	id := func(x int32) int32 { return x }
+	or := func(x, y int32) int32 { return x | y }
+	and := func(x, y int32) int32 { return x & y }
+	y := func(x, y int32) int32 { return y }
+
+	for _, test := range [...]struct {
+		name   string
+		f      func(int32) int32
+		golden func(int32) int32
+	}{
+		{"x|x", func(x int32) int32 { return x | x }, id},
+		{"x|0", func(x int32) int32 { return x | 0 }, id},
+		{"x|-1", func(x int32) int32 { return x | -1 }, func(x int32) int32 { return -1 }},
+		{"x&x", func(x int32) int32 { return x & x }, id},
+		{"x&0", func(x int32) int32 { return x & 0 }, zero},
+		{"x&-1", func(x int32) int32 { return x & -1 }, id},
+		{"x^x", func(x int32) int32 { return x ^ x }, zero},
+		{"x^0", func(x int32) int32 { return x ^ 0 }, id},
+		{"x^-1", func(x int32) int32 { return x ^ -1 }, func(x int32) int32 { return ^x }},
+		{"x+0", func(x int32) int32 { return x + 0 }, id},
+		{"x-x", func(x int32) int32 { return x - x }, zero},
+		{"x*0", func(x int32) int32 { return x * 0 }, zero},
+		{"^^x", func(x int32) int32 { return ^^x }, id},
+	} {
+		for _, v := range values {
+			got := test.f(v)
+			want := test.golden(v)
+			if want != got {
+				t.Errorf("[%s](%d)=%d, want %d", test.name, v, got, want)
+			}
+		}
+	}
+	for _, test := range [...]struct {
+		name   string
+		f      func(int32, int32) int32
+		golden func(int32, int32) int32
+	}{
+		{"x|(x|y)", func(x, y int32) int32 { return x | (x | y) }, or},
+		{"x|(y|x)", func(x, y int32) int32 { return x | (y | x) }, or},
+		{"(x|y)|x", func(x, y int32) int32 { return (x | y) | x }, or},
+		{"(y|x)|x", func(x, y int32) int32 { return (y | x) | x }, or},
+		{"x&(x&y)", func(x, y int32) int32 { return x & (x & y) }, and},
+		{"x&(y&x)", func(x, y int32) int32 { return x & (y & x) }, and},
+		{"(x&y)&x", func(x, y int32) int32 { return (x & y) & x }, and},
+		{"(y&x)&x", func(x, y int32) int32 { return (y & x) & x }, and},
+		{"x^(x^y)", func(x, y int32) int32 { return x ^ (x ^ y) }, y},
+		{"x^(y^x)", func(x, y int32) int32 { return x ^ (y ^ x) }, y},
+		{"(x^y)^x", func(x, y int32) int32 { return (x ^ y) ^ x }, y},
+		{"(y^x)^x", func(x, y int32) int32 { return (y ^ x) ^ x }, y},
+		{"-(y-x)", func(x, y int32) int32 { return -(y - x) }, func(x, y int32) int32 { return x - y }},
+		{"(x+y)-x", func(x, y int32) int32 { return (x + y) - x }, y},
+		{"(y+x)-x", func(x, y int32) int32 { return (y + x) - x }, y},
+	} {
+		for _, v := range values {
+			for _, w := range values {
+				got := test.f(v, w)
+				want := test.golden(v, w)
+				if want != got {
+					t.Errorf("[%s](%d,%d)=%d, want %d", test.name, v, w, got, want)
+				}
+			}
+		}
+	}
+}
+
+func TestLogic16(t *testing.T) {
+	// test values to determine function equality
+	values := [...]int16{-1 << 15, 1<<15 - 1, -4, -3, -2, -1, 0, 1, 2, 3, 4}
+
+	// golden functions we use repeatedly
+	zero := func(x int16) int16 { return 0 }
+	id := func(x int16) int16 { return x }
+	or := func(x, y int16) int16 { return x | y }
+	and := func(x, y int16) int16 { return x & y }
+	y := func(x, y int16) int16 { return y }
+
+	for _, test := range [...]struct {
+		name   string
+		f      func(int16) int16
+		golden func(int16) int16
+	}{
+		{"x|x", func(x int16) int16 { return x | x }, id},
+		{"x|0", func(x int16) int16 { return x | 0 }, id},
+		{"x|-1", func(x int16) int16 { return x | -1 }, func(x int16) int16 { return -1 }},
+		{"x&x", func(x int16) int16 { return x & x }, id},
+		{"x&0", func(x int16) int16 { return x & 0 }, zero},
+		{"x&-1", func(x int16) int16 { return x & -1 }, id},
+		{"x^x", func(x int16) int16 { return x ^ x }, zero},
+		{"x^0", func(x int16) int16 { return x ^ 0 }, id},
+		{"x^-1", func(x int16) int16 { return x ^ -1 }, func(x int16) int16 { return ^x }},
+		{"x+0", func(x int16) int16 { return x + 0 }, id},
+		{"x-x", func(x int16) int16 { return x - x }, zero},
+		{"x*0", func(x int16) int16 { return x * 0 }, zero},
+		{"^^x", func(x int16) int16 { return ^^x }, id},
+	} {
+		for _, v := range values {
+			got := test.f(v)
+			want := test.golden(v)
+			if want != got {
+				t.Errorf("[%s](%d)=%d, want %d", test.name, v, got, want)
+			}
+		}
+	}
+	for _, test := range [...]struct {
+		name   string
+		f      func(int16, int16) int16
+		golden func(int16, int16) int16
+	}{
+		{"x|(x|y)", func(x, y int16) int16 { return x | (x | y) }, or},
+		{"x|(y|x)", func(x, y int16) int16 { return x | (y | x) }, or},
+		{"(x|y)|x", func(x, y int16) int16 { return (x | y) | x }, or},
+		{"(y|x)|x", func(x, y int16) int16 { return (y | x) | x }, or},
+		{"x&(x&y)", func(x, y int16) int16 { return x & (x & y) }, and},
+		{"x&(y&x)", func(x, y int16) int16 { return x & (y & x) }, and},
+		{"(x&y)&x", func(x, y int16) int16 { return (x & y) & x }, and},
+		{"(y&x)&x", func(x, y int16) int16 { return (y & x) & x }, and},
+		{"x^(x^y)", func(x, y int16) int16 { return x ^ (x ^ y) }, y},
+		{"x^(y^x)", func(x, y int16) int16 { return x ^ (y ^ x) }, y},
+		{"(x^y)^x", func(x, y int16) int16 { return (x ^ y) ^ x }, y},
+		{"(y^x)^x", func(x, y int16) int16 { return (y ^ x) ^ x }, y},
+		{"-(y-x)", func(x, y int16) int16 { return -(y - x) }, func(x, y int16) int16 { return x - y }},
+		{"(x+y)-x", func(x, y int16) int16 { return (x + y) - x }, y},
+		{"(y+x)-x", func(x, y int16) int16 { return (y + x) - x }, y},
+	} {
+		for _, v := range values {
+			for _, w := range values {
+				got := test.f(v, w)
+				want := test.golden(v, w)
+				if want != got {
+					t.Errorf("[%s](%d,%d)=%d, want %d", test.name, v, w, got, want)
+				}
+			}
+		}
+	}
+}
+
+func TestLogic8(t *testing.T) {
+	// test values to determine function equality
+	values := [...]int8{-1 << 7, 1<<7 - 1, -4, -3, -2, -1, 0, 1, 2, 3, 4}
+
+	// golden functions we use repeatedly
+	zero := func(x int8) int8 { return 0 }
+	id := func(x int8) int8 { return x }
+	or := func(x, y int8) int8 { return x | y }
+	and := func(x, y int8) int8 { return x & y }
+	y := func(x, y int8) int8 { return y }
+
+	for _, test := range [...]struct {
+		name   string
+		f      func(int8) int8
+		golden func(int8) int8
+	}{
+		{"x|x", func(x int8) int8 { return x | x }, id},
+		{"x|0", func(x int8) int8 { return x | 0 }, id},
+		{"x|-1", func(x int8) int8 { return x | -1 }, func(x int8) int8 { return -1 }},
+		{"x&x", func(x int8) int8 { return x & x }, id},
+		{"x&0", func(x int8) int8 { return x & 0 }, zero},
+		{"x&-1", func(x int8) int8 { return x & -1 }, id},
+		{"x^x", func(x int8) int8 { return x ^ x }, zero},
+		{"x^0", func(x int8) int8 { return x ^ 0 }, id},
+		{"x^-1", func(x int8) int8 { return x ^ -1 }, func(x int8) int8 { return ^x }},
+		{"x+0", func(x int8) int8 { return x + 0 }, id},
+		{"x-x", func(x int8) int8 { return x - x }, zero},
+		{"x*0", func(x int8) int8 { return x * 0 }, zero},
+		{"^^x", func(x int8) int8 { return ^^x }, id},
+	} {
+		for _, v := range values {
+			got := test.f(v)
+			want := test.golden(v)
+			if want != got {
+				t.Errorf("[%s](%d)=%d, want %d", test.name, v, got, want)
+			}
+		}
+	}
+	for _, test := range [...]struct {
+		name   string
+		f      func(int8, int8) int8
+		golden func(int8, int8) int8
+	}{
+		{"x|(x|y)", func(x, y int8) int8 { return x | (x | y) }, or},
+		{"x|(y|x)", func(x, y int8) int8 { return x | (y | x) }, or},
+		{"(x|y)|x", func(x, y int8) int8 { return (x | y) | x }, or},
+		{"(y|x)|x", func(x, y int8) int8 { return (y | x) | x }, or},
+		{"x&(x&y)", func(x, y int8) int8 { return x & (x & y) }, and},
+		{"x&(y&x)", func(x, y int8) int8 { return x & (y & x) }, and},
+		{"(x&y)&x", func(x, y int8) int8 { return (x & y) & x }, and},
+		{"(y&x)&x", func(x, y int8) int8 { return (y & x) & x }, and},
+		{"x^(x^y)", func(x, y int8) int8 { return x ^ (x ^ y) }, y},
+		{"x^(y^x)", func(x, y int8) int8 { return x ^ (y ^ x) }, y},
+		{"(x^y)^x", func(x, y int8) int8 { return (x ^ y) ^ x }, y},
+		{"(y^x)^x", func(x, y int8) int8 { return (y ^ x) ^ x }, y},
+		{"-(y-x)", func(x, y int8) int8 { return -(y - x) }, func(x, y int8) int8 { return x - y }},
+		{"(x+y)-x", func(x, y int8) int8 { return (x + y) - x }, y},
+		{"(y+x)-x", func(x, y int8) int8 { return (y + x) - x }, y},
+	} {
+		for _, v := range values {
+			for _, w := range values {
+				got := test.f(v, w)
+				want := test.golden(v, w)
+				if want != got {
+					t.Errorf("[%s](%d,%d)=%d, want %d", test.name, v, w, got, want)
+				}
+			}
+		}
+	}
+}