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61945fc502
We know that a & 31 is non-negative for all a, signed or not. We can avoid checking that and needing to write out an unreachable call to panicshift. Change-Id: I32f32fb2c950d2b2b35ac5c0e99b7b2dbd47f917 Reviewed-on: https://go-review.googlesource.com/c/go/+/167499 Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> Reviewed-by: Keith Randall <khr@golang.org>
128 lines
2.6 KiB
Go
128 lines
2.6 KiB
Go
// asmcheck
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// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package codegen
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// ------------------ //
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// masked shifts //
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// ------------------ //
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func lshMask64x64(v int64, s uint64) int64 {
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// s390x:-".*AND",-".*MOVDGE"
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return v << (s & 63)
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}
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func rshMask64Ux64(v uint64, s uint64) uint64 {
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// s390x:-".*AND",-".*MOVDGE"
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return v >> (s & 63)
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}
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func rshMask64x64(v int64, s uint64) int64 {
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// s390x:-".*AND",-".*MOVDGE"
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return v >> (s & 63)
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}
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func lshMask32x64(v int32, s uint64) int32 {
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// s390x:-".*AND",-".*MOVDGE"
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return v << (s & 63)
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}
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func rshMask32Ux64(v uint32, s uint64) uint32 {
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// s390x:-".*AND",-".*MOVDGE"
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return v >> (s & 63)
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}
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func rshMask32x64(v int32, s uint64) int32 {
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// s390x:-".*AND",-".*MOVDGE"
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return v >> (s & 63)
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}
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func lshMask64x32(v int64, s uint32) int64 {
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// s390x:-".*AND",-".*MOVDGE"
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return v << (s & 63)
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}
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func rshMask64Ux32(v uint64, s uint32) uint64 {
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// s390x:-".*AND",-".*MOVDGE"
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return v >> (s & 63)
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}
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func rshMask64x32(v int64, s uint32) int64 {
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// s390x:-".*AND",-".*MOVDGE"
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return v >> (s & 63)
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}
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func lshMask64x32Ext(v int64, s int32) int64 {
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// s390x:-".*AND",-".*MOVDGE"
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return v << uint(s&63)
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}
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func rshMask64Ux32Ext(v uint64, s int32) uint64 {
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// s390x:-".*AND",-".*MOVDGE"
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return v >> uint(s&63)
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}
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func rshMask64x32Ext(v int64, s int32) int64 {
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// s390x:-".*AND",-".*MOVDGE"
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return v >> uint(s&63)
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}
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// --------------- //
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// signed shifts //
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// --------------- //
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// We do want to generate a test + panicshift for these cases.
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func lshSigned(v8 int8, v16 int16, v32 int32, v64 int64, x int) {
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// amd64:"TESTB"
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_ = x << v8
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// amd64:"TESTW"
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_ = x << v16
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// amd64:"TESTL"
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_ = x << v32
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// amd64:"TESTQ"
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_ = x << v64
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}
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// We want to avoid generating a test + panicshift for these cases.
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func lshSignedMasked(v8 int8, v16 int16, v32 int32, v64 int64, x int) {
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// amd64:-"TESTB"
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_ = x << (v8 & 7)
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// amd64:-"TESTW"
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_ = x << (v16 & 15)
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// amd64:-"TESTL"
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_ = x << (v32 & 31)
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// amd64:-"TESTQ"
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_ = x << (v64 & 63)
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}
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// ------------------ //
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// bounded shifts //
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// ------------------ //
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func lshGuarded64(v int64, s uint) int64 {
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if s < 64 {
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// s390x:-".*AND",-".*MOVDGE"
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return v >> s
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}
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panic("shift too large")
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}
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func rshGuarded64U(v uint64, s uint) uint64 {
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if s < 64 {
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// s390x:-".*AND",-".*MOVDGE"
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return v >> s
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}
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panic("shift too large")
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}
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func rshGuarded64(v int64, s uint) int64 {
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if s < 64 {
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// s390x:-".*AND",-".*MOVDGE"
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return v << s
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}
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panic("shift too large")
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}
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