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	 f5e6d3e879
			
		
	
	
		f5e6d3e879
		
	
	
	
	
		
			
			This CL adds rewrite rules for CSETM, CSINC, CSINV, and CSNEG. By adding
these rules, we can save one instruction.
For example,
  func test(cond bool, a int) int {
    if cond {
      a++
    }
    return a
  }
Before:
  MOVD "".a+8(RSP), R0
  ADD $1, R0, R1
  MOVBU "".cond(RSP), R2
  CMPW $0, R2
  CSEL NE, R1, R0, R0
After:
  MOVBU "".cond(RSP), R0
  CMPW $0, R0
  MOVD "".a+8(RSP), R0
  CSINC EQ, R0, R0, R0
This patch is a copy of CL 285694. Co-authored-by: JunchenLi
<junchen.li@arm.com>
Change-Id: Ic1a79e8b8ece409b533becfcb7950f11e7b76f24
Reviewed-on: https://go-review.googlesource.com/c/go/+/302231
Trust: fannie zhang <Fannie.Zhang@arm.com>
Run-TryBot: fannie zhang <Fannie.Zhang@arm.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
		
	
			
		
			
				
	
	
		
			402 lines
		
	
	
	
		
			5.3 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			402 lines
		
	
	
	
		
			5.3 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
| // asmcheck
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| 
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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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| 
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| package codegen
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| 
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| func cmovint(c int) int {
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| 	x := c + 4
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| 	if x < 0 {
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| 		x = 182
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| 	}
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| 	// amd64:"CMOVQLT"
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| 	// arm64:"CSEL\tLT"
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| 	// wasm:"Select"
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| 	return x
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| }
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| 
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| func cmovchan(x, y chan int) chan int {
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| 	if x != y {
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| 		x = y
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| 	}
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| 	// amd64:"CMOVQNE"
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| 	// arm64:"CSEL\tNE"
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| 	// wasm:"Select"
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| 	return x
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| }
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| 
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| func cmovuintptr(x, y uintptr) uintptr {
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| 	if x < y {
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| 		x = -y
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| 	}
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| 	// amd64:"CMOVQ(HI|CS)"
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| 	// arm64:"CSNEG\tLS"
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| 	// wasm:"Select"
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| 	return x
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| }
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| 
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| func cmov32bit(x, y uint32) uint32 {
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| 	if x < y {
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| 		x = -y
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| 	}
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| 	// amd64:"CMOVL(HI|CS)"
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| 	// arm64:"CSNEG\t(LS|HS)"
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| 	// wasm:"Select"
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| 	return x
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| }
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| 
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| func cmov16bit(x, y uint16) uint16 {
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| 	if x < y {
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| 		x = -y
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| 	}
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| 	// amd64:"CMOVW(HI|CS)"
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| 	// arm64:"CSNEG\t(LS|HS)"
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| 	// wasm:"Select"
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| 	return x
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| }
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| 
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| // Floating point comparison. For EQ/NE, we must
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| // generate special code to handle NaNs.
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| func cmovfloateq(x, y float64) int {
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| 	a := 128
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| 	if x == y {
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| 		a = 256
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| 	}
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| 	// amd64:"CMOVQNE","CMOVQPC"
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| 	// arm64:"CSEL\tEQ"
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| 	// wasm:"Select"
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| 	return a
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| }
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| 
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| func cmovfloatne(x, y float64) int {
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| 	a := 128
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| 	if x != y {
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| 		a = 256
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| 	}
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| 	// amd64:"CMOVQNE","CMOVQPS"
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| 	// arm64:"CSEL\tNE"
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| 	// wasm:"Select"
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| 	return a
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| }
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| 
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| //go:noinline
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| func frexp(f float64) (frac float64, exp int) {
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| 	return 1.0, 4
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| }
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| 
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| //go:noinline
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| func ldexp(frac float64, exp int) float64 {
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| 	return 1.0
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| }
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| 
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| // Generate a CMOV with a floating comparison and integer move.
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| func cmovfloatint2(x, y float64) float64 {
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| 	yfr, yexp := 4.0, 5
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| 
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| 	r := x
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| 	for r >= y {
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| 		rfr, rexp := frexp(r)
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| 		if rfr < yfr {
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| 			rexp = rexp - 1
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| 		}
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| 		// amd64:"CMOVQHI"
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| 		// arm64:"CSEL\tMI"
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| 		// wasm:"Select"
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| 		r = r - ldexp(y, rexp-yexp)
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| 	}
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| 	return r
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| }
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| 
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| func cmovloaded(x [4]int, y int) int {
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| 	if x[2] != 0 {
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| 		y = x[2]
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| 	} else {
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| 		y = y >> 2
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| 	}
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| 	// amd64:"CMOVQNE"
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| 	// arm64:"CSEL\tNE"
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| 	// wasm:"Select"
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| 	return y
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| }
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| 
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| func cmovuintptr2(x, y uintptr) uintptr {
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| 	a := x * 2
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| 	if a == 0 {
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| 		a = 256
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| 	}
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| 	// amd64:"CMOVQEQ"
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| 	// arm64:"CSEL\tEQ"
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| 	// wasm:"Select"
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| 	return a
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| }
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| 
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| // Floating point CMOVs are not supported by amd64/arm64
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| func cmovfloatmove(x, y int) float64 {
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| 	a := 1.0
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| 	if x <= y {
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| 		a = 2.0
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| 	}
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| 	// amd64:-"CMOV"
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| 	// arm64:-"CSEL"
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| 	// wasm:-"Select"
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| 	return a
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| }
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| 
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| // On amd64, the following patterns trigger comparison inversion.
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| // Test that we correctly invert the CMOV condition
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| var gsink int64
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| var gusink uint64
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| 
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| func cmovinvert1(x, y int64) int64 {
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| 	if x < gsink {
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| 		y = -y
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| 	}
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| 	// amd64:"CMOVQGT"
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| 	return y
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| }
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| func cmovinvert2(x, y int64) int64 {
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| 	if x <= gsink {
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| 		y = -y
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| 	}
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| 	// amd64:"CMOVQGE"
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| 	return y
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| }
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| func cmovinvert3(x, y int64) int64 {
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| 	if x == gsink {
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| 		y = -y
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| 	}
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| 	// amd64:"CMOVQEQ"
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| 	return y
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| }
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| func cmovinvert4(x, y int64) int64 {
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| 	if x != gsink {
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| 		y = -y
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| 	}
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| 	// amd64:"CMOVQNE"
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| 	return y
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| }
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| func cmovinvert5(x, y uint64) uint64 {
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| 	if x > gusink {
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| 		y = -y
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| 	}
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| 	// amd64:"CMOVQCS"
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| 	return y
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| }
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| func cmovinvert6(x, y uint64) uint64 {
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| 	if x >= gusink {
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| 		y = -y
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| 	}
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| 	// amd64:"CMOVQLS"
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| 	return y
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| }
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| 
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| func cmovload(a []int, i int, b bool) int {
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| 	if b {
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| 		i++
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| 	}
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| 	// See issue 26306
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| 	// amd64:-"CMOVQNE"
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| 	return a[i]
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| }
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| 
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| func cmovstore(a []int, i int, b bool) {
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| 	if b {
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| 		i++
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| 	}
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| 	// amd64:"CMOVQNE"
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| 	a[i] = 7
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| }
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| 
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| var r0, r1, r2, r3, r4, r5 int
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| 
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| func cmovinc(cond bool, a, b, c int) {
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| 	var x0, x1 int
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| 
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| 	if cond {
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| 		x0 = a
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| 	} else {
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| 		x0 = b + 1
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| 	}
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| 	// arm64:"CSINC\tNE", -"CSEL"
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| 	r0 = x0
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| 
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| 	if cond {
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| 		x1 = b + 1
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| 	} else {
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| 		x1 = a
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| 	}
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| 	// arm64:"CSINC\tEQ", -"CSEL"
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| 	r1 = x1
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| 
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| 	if cond {
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| 		c++
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| 	}
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| 	// arm64:"CSINC\tEQ", -"CSEL"
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| 	r2 = c
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| }
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| 
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| func cmovinv(cond bool, a, b int) {
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| 	var x0, x1 int
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| 
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| 	if cond {
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| 		x0 = a
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| 	} else {
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| 		x0 = ^b
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| 	}
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| 	// arm64:"CSINV\tNE", -"CSEL"
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| 	r0 = x0
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| 
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| 	if cond {
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| 		x1 = ^b
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| 	} else {
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| 		x1 = a
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| 	}
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| 	// arm64:"CSINV\tEQ", -"CSEL"
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| 	r1 = x1
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| }
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| 
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| func cmovneg(cond bool, a, b, c int) {
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| 	var x0, x1 int
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| 
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| 	if cond {
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| 		x0 = a
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| 	} else {
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| 		x0 = -b
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| 	}
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| 	// arm64:"CSNEG\tNE", -"CSEL"
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| 	r0 = x0
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| 
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| 	if cond {
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| 		x1 = -b
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| 	} else {
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| 		x1 = a
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| 	}
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| 	// arm64:"CSNEG\tEQ", -"CSEL"
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| 	r1 = x1
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| }
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| 
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| func cmovsetm(cond bool, x int) {
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| 	var x0, x1 int
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| 
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| 	if cond {
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| 		x0 = -1
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| 	} else {
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| 		x0 = 0
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| 	}
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| 	// arm64:"CSETM\tNE", -"CSEL"
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| 	r0 = x0
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| 
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| 	if cond {
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| 		x1 = 0
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| 	} else {
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| 		x1 = -1
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| 	}
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| 	// arm64:"CSETM\tEQ", -"CSEL"
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| 	r1 = x1
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| }
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| 
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| func cmovFcmp0(s, t float64, a, b int) {
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| 	var x0, x1, x2, x3, x4, x5 int
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| 
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| 	if s < t {
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| 		x0 = a
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| 	} else {
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| 		x0 = b + 1
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| 	}
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| 	// arm64:"CSINC\tMI", -"CSEL"
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| 	r0 = x0
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| 
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| 	if s <= t {
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| 		x1 = a
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| 	} else {
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| 		x1 = ^b
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| 	}
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| 	// arm64:"CSINV\tLS", -"CSEL"
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| 	r1 = x1
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| 
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| 	if s > t {
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| 		x2 = a
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| 	} else {
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| 		x2 = -b
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| 	}
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| 	// arm64:"CSNEG\tMI", -"CSEL"
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| 	r2 = x2
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| 
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| 	if s >= t {
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| 		x3 = -1
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| 	} else {
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| 		x3 = 0
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| 	}
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| 	// arm64:"CSETM\tLS", -"CSEL"
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| 	r3 = x3
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| 
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| 	if s == t {
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| 		x4 = a
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| 	} else {
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| 		x4 = b + 1
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| 	}
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| 	// arm64:"CSINC\tEQ", -"CSEL"
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| 	r4 = x4
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| 
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| 	if s != t {
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| 		x5 = a
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| 	} else {
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| 		x5 = b + 1
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| 	}
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| 	// arm64:"CSINC\tNE", -"CSEL"
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| 	r5 = x5
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| }
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| 
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| func cmovFcmp1(s, t float64, a, b int) {
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| 	var x0, x1, x2, x3, x4, x5 int
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| 
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| 	if s < t {
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| 		x0 = b + 1
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| 	} else {
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| 		x0 = a
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| 	}
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| 	// arm64:"CSINC\tPL", -"CSEL"
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| 	r0 = x0
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| 
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| 	if s <= t {
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| 		x1 = ^b
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| 	} else {
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| 		x1 = a
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| 	}
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| 	// arm64:"CSINV\tHI", -"CSEL"
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| 	r1 = x1
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| 
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| 	if s > t {
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| 		x2 = -b
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| 	} else {
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| 		x2 = a
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| 	}
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| 	// arm64:"CSNEG\tPL", -"CSEL"
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| 	r2 = x2
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| 
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| 	if s >= t {
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| 		x3 = 0
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| 	} else {
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| 		x3 = -1
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| 	}
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| 	// arm64:"CSETM\tHI", -"CSEL"
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| 	r3 = x3
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| 
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| 	if s == t {
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| 		x4 = b + 1
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| 	} else {
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| 		x4 = a
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| 	}
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| 	// arm64:"CSINC\tNE", -"CSEL"
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| 	r4 = x4
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| 
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| 	if s != t {
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| 		x5 = b + 1
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| 	} else {
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| 		x5 = a
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| 	}
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| 	// arm64:"CSINC\tEQ", -"CSEL"
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| 	r5 = x5
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| }
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