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85a8d25d53
cmd/asm now supports three-operand form of IMUL,
so instead of using IMUL with resultInArg0, emit IMUL3 instruction.
This results in less redundant MOVs where SSA assigns
different registers to input[0] and dst arguments.
Note: these have exactly the same encoding when reg0=reg1:
IMUL3x $const, reg0, reg1
IMULx $const, reg
Two-operand IMULx is like a crippled IMUL3x, with dst fixed to input[0].
This is why we don't bother to generate IMULx for the case where
dst is the same as input[0].
Change-Id: I4becda475b3dffdd07b6fdf1c75bacc82af654e4
Reviewed-on: https://go-review.googlesource.com/99656
Run-TryBot: Iskander Sharipov <iskander.sharipov@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Giovanni Bajo <rasky@develer.com>
Reviewed-by: Keith Randall <khr@golang.org>
61 lines
1.3 KiB
Go
61 lines
1.3 KiB
Go
// asmcheck
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// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package codegen
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// This file contains codegen tests related to arithmetic
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// simplifications/optimizations.
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func Pow2Muls(n1, n2 int) (int, int) {
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// amd64:"SHLQ\t[$]5",-"IMULQ"
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// 386:"SHLL\t[$]5",-"IMULL"
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// arm:"SLL\t[$]5",-"MUL"
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// arm64:"LSL\t[$]5",-"MUL"
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a := n1 * 32
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// amd64:"SHLQ\t[$]6",-"IMULQ"
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// 386:"SHLL\t[$]6",-"IMULL"
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// arm:"SLL\t[$]6",-"MUL"
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// arm64:"LSL\t[$]6",-"MUL"
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b := -64 * n2
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return a, b
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}
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// ------------------ //
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// MULs merging //
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// ------------------ //
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func MergeMuls1(n int) int {
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// amd64:"IMUL3Q\t[$]46"
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// 386:"IMUL3L\t[$]46"
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return 15*n + 31*n // 46n
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}
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func MergeMuls2(n int) int {
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// amd64:"IMUL3Q\t[$]23","ADDQ\t[$]29"
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// 386:"IMUL3L\t[$]23","ADDL\t[$]29"
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return 5*n + 7*(n+1) + 11*(n+2) // 23n + 29
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}
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func MergeMuls3(a, n int) int {
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// amd64:"ADDQ\t[$]19",-"IMULQ\t[$]19"
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// 386:"ADDL\t[$]19",-"IMULL\t[$]19"
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return a*n + 19*n // (a+19)n
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}
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func MergeMuls4(n int) int {
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// amd64:"IMUL3Q\t[$]14"
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// 386:"IMUL3L\t[$]14"
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return 23*n - 9*n // 14n
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}
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func MergeMuls5(a, n int) int {
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// amd64:"ADDQ\t[$]-19",-"IMULQ\t[$]19"
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// 386:"ADDL\t[$]-19",-"IMULL\t[$]19"
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return a*n - 19*n // (a-19)n
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}
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