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69aed4712d
Currently we use a full cmpstring to do the comparison for each split in the binary search for a string switch. Instead, split by comparing a single byte of the input string with a constant. That will give us a much faster split (although it might be not quite as good a split). Fixes #53333 R=go1.20 Change-Id: I28c7209342314f367071e4aa1f2beb6ec9ff7123 Reviewed-on: https://go-review.googlesource.com/c/go/+/414894 TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Keith Randall <khr@golang.org> Reviewed-by: David Chase <drchase@google.com> Reviewed-by: Heschi Kreinick <heschi@google.com>
101 lines
1.8 KiB
Go
101 lines
1.8 KiB
Go
// asmcheck
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// Copyright 2019 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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// These tests check code generation of switch statements.
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package codegen
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// see issue 33934
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func f(x string) int {
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// amd64:-`cmpstring`
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switch x {
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case "":
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return -1
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case "1", "2", "3":
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return -2
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default:
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return -3
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}
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}
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// use jump tables for 8+ int cases
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func square(x int) int {
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// amd64:`JMP\s\(.*\)\(.*\)$`
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// arm64:`MOVD\s\(R.*\)\(R.*<<3\)`,`JMP\s\(R.*\)$`
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switch x {
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case 1:
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return 1
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case 2:
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return 4
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case 3:
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return 9
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case 4:
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return 16
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case 5:
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return 25
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case 6:
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return 36
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case 7:
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return 49
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case 8:
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return 64
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default:
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return x * x
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}
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}
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// use jump tables for 8+ string lengths
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func length(x string) int {
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// amd64:`JMP\s\(.*\)\(.*\)$`
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// arm64:`MOVD\s\(R.*\)\(R.*<<3\)`,`JMP\s\(R.*\)$`
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switch x {
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case "a":
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return 1
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case "bb":
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return 2
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case "ccc":
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return 3
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case "dddd":
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return 4
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case "eeeee":
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return 5
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case "ffffff":
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return 6
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case "ggggggg":
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return 7
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case "hhhhhhhh":
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return 8
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default:
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return len(x)
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}
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}
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// Use single-byte ordered comparisons for binary searching strings.
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// See issue 53333.
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func mimetype(ext string) string {
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// amd64: `CMPB\s1\(.*\), \$104$`,-`cmpstring`
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// arm64: `MOVB\s1\(R.*\), R.*$`, `CMPW\s\$104, R.*$`, -`cmpstring`
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switch ext {
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// amd64: `CMPL\s\(.*\), \$1836345390$`
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// arm64: `CMPW\s\$1836345390, R.*$`
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case ".htm":
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return "A"
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// amd64: `CMPL\s\(.*\), \$1953457454$`
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// arm64: `CMPW\s\$1953457454, R.*$`
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case ".eot":
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return "B"
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// amd64: `CMPL\s\(.*\), \$1735815982$`
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// arm64: `CMPW\s\$1735815982, R.*$`
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case ".svg":
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return "C"
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// amd64: `CMPL\s\(.*\), \$1718907950$`
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// arm64: `CMPW\s\$1718907950, R.*$`
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case ".ttf":
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return "D"
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default:
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return ""
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}
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}
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