}

func shifts8() {
	// shift examples from shift discussion: better error messages
	var s uint
	_ = 1.0 /* ERROR "shifted operand 1.0 (type float64) must be integer" */ <<s == 1
	_ = 1.0 /* ERROR "shifted operand 1.0 (type float64) must be integer" */ <<s == 1.0
	_ = 1 /* ERROR "shifted operand 1 (type float64) must be integer" */ <<s == 1.0

DATA shifts<>+0x28(SB)/4, $0xffffffff
DATA shifts<>+0x2c(SB)/4, $0xffffffff

DATA shifts<>+0x30(SB)/4, $0xff0f0e0d
DATA shifts<>+0x34(SB)/4, $0xffffffff
DATA shifts<>+0x38(SB)/4, $0xffffffff
DATA shifts<>+0x3c(SB)/4, $0xffffffff

DATA shifts<>+0x40(SB)/4, $0x0f0e0d0c
DATA shifts<>+0x44(SB)/4, $0xffffffff
DATA shifts<>+0x48(SB)/4, $0xffffffff
DATA shifts<>+0x4c(SB)/4, $0xffffffff

	if shift >= 0 && shift < 64 {
		// arm64:"LSL",-"CSEL"
		r1 = val64 << shift
	}
	if shift >= 0 && shift < 32 {
		// arm64:"LSL",-"CSEL"
		r2 = val32 << shift
	}
	if shift >= 0 && shift < 16 {
		// arm64:"LSL",-"CSEL"
		r3 = val16 << shift
	}
	if shift >= 0 && shift < 8 {
		// arm64:"LSL",-"CSEL"
		r4 = val8 << shift
	}
	return r1, r2, r3, r4

}

func sh32x64(n int32) int32 {
	if n < 0 {
		return n
	}
	return n >> uint64(31) // ERROR "Proved Rsh32x64 shifts to zero"
}

func sh16(n int16) int16 {
	if n < 0 {
		return n
	}
	return n >> 15 // ERROR "Proved Rsh16x64 shifts to zero"
}

func sh64noopt(n int64) int64 {
	return n >> 63 // not optimized; n could be negative
}

"src/compress/flate/testdata/huffman-rand-max.in", "src/compress/flate/testdata/huffman-shifts.dyn.expect", "src/compress/flate/testdata/huffman-shifts.dyn.expect-noinput", "src/compress/flate/testdata/huffman-shifts.golden", "src/compress/flate/testdata/huffman-shifts.in", "src/compress/flate/testdata/huffman-shifts.wb.expect", "src/compress/flate/testdata/huffman-shifts.wb.expect-noinput", "src/compress/flate/testdata/huffman-text-shift.dyn.expect", "src/compress/flate/testdata/huffman-text-shift.dyn.expect-noinput",...

(Rsh64x64 [c] x (Int64Make (Const32 [0]) lo)) => (Rsh64x32 [c] x lo)
(Rsh64Ux64 [c] x (Int64Make (Const32 [0]) lo)) => (Rsh64Ux32 [c] x lo)

// turn x64 non-constant shifts to x32 shifts
// if high 32-bit of the shift is nonzero, make a huge shift
(Lsh64x64 x (Int64Make hi lo)) && hi.Op != OpConst32 =>
       (Lsh64x32 x (Or32 <typ.UInt32> (Zeromask hi) lo))
(Rsh64x64 x (Int64Make hi lo)) && hi.Op != OpConst32 =>

specified alignment.

6. Shift instructions

The simple scalar shifts on PPC64 expect a shift count that fits in 5 bits for
32-bit values or 6 bit for 64-bit values. If the shift count is a constant value
greater than the max then the assembler sets it to the max for that size (31 for
32 bit values, 63 for 64 bit values). If the shift count is in a register, then

	{"$1000000000", "$1000000000"},
	{"$__tsan_func_enter(SB)", "$__tsan_func_enter(SB)"},
	{"$main(SB)", "$main(SB)"},
	{"$masks<>(SB)", "$masks<>(SB)"},
	{"$setg_gcc<>(SB)", "$setg_gcc<>(SB)"},
	{"$shifts<>(SB)", "$shifts<>(SB)"},
	{"$~(1<<63)", "$9223372036854775807"},
	{"$~0x3F", "$-64"},
	{"$~15", "$-16"},
	{"(((8)&0xf)*4)(SP)", "32(SP)"},
	{"(((8-14)&0xf)*4)(SP)", "40(SP)"},
	{"(6+8)(AX)", "14(AX)"},

(Rsh8Ux64 [c] x y) => (Rsh64Ux64 [c] (ZeroExt8to64 x) y)
(Rsh8Ux(32|16|8) [c] x y) => (Rsh64Ux64 [c] (ZeroExt8to64 x) (ZeroExt(32|16|8)to64 y))

// Signed right shift needs to return 0/-1 if shift amount is >= width of shifted value.
// We implement this by setting the shift value to (width - 1) if the shift value is >= width.

(Rsh64x64 x y) && shiftIsBounded(v) => (I64ShrS x y)
(Rsh64x64 x (I64Const [c])) && uint64(c) < 64 => (I64ShrS x (I64Const [c]))

(Avg32u <t> x y) => (ADD (SRLconst <t> (SUB <t> x y) [1]) y)

(And(32|16|8) ...) => (AND ...)
(Or(32|16|8) ...) => (OR ...)
(Xor(32|16|8) ...) => (XOR ...)

// constant shifts
// generic opt rewrites all constant shifts to shift by Const64
(Lsh32x64  x (Const64 [c])) && uint32(c) < 32 => (SLLconst x [int32(c)])
(Rsh32x64  x (Const64 [c])) && uint32(c) < 32 => (SRAconst x [int32(c)])