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cmd/compile: "illegal combination SRA ADDCON REG REG" on mips #42587

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ALTree opened this issue Nov 13, 2020 · 2 comments
Closed

cmd/compile: "illegal combination SRA ADDCON REG REG" on mips #42587

ALTree opened this issue Nov 13, 2020 · 2 comments
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FrozenDueToAge NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one.
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Go1.16

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@ALTree
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ALTree commented Nov 13, 2020 

$ go version
go version go1.15.5 linux/amd64

$ gotip version
go version devel +f423d616b1 Fri Nov 13 15:15:15 2020 +0000 linux/amd64

The following program:

package p

func f() {
	var i, j int
	_ = func() {
		i = 32
		j = j>>i | len([]int{})
	}
}

Crashes the go1.15.5 and tip compilers when built for mips:

$ GOARCH=mips go tool compile crash.go 

00020 (crash.go:7)	SRA	$-1, R2, R2
00020 (crash.go:7)	SRA	$-1, R2, R2
00020 (crash.go:7)	SRA	$-1, R2, R2
00020 (crash.go:7)	SRA	$-1, R2, R2
crash.go:7:5: illegal combination SRA ADDCON REG REG

The go1.14.12 compiler compiles it with no issues.

cc @cherrymui @randall77
@ALTree ALTree added the NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one. label Nov 13, 2020
@ALTree ALTree added this to the Go1.16 milestone Nov 13, 2020
@gopherbot
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Change https://golang.org/cl/270117 mentions this issue: cmd/compile: check unsigned value for SRA mips rule

@gopherbot
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Change https://golang.org/cl/270558 mentions this issue: cmd/compile: stop MOVW-ing -1 as SRA shift amount in mips

gopherbot pushed a commit that referenced this issue Nov 18, 2020
@ALTree
cmd/compile: stop MOVW-ing -1 as SRA shift amount in mips
399b5d1 
The shift amount in SRAconst needs to be in the [0,31] range, so stop
MOVWing -1 to SRA in the Rsh lowering rules.

Also see CL 270117.

Passes

  $ GOARCH=mips go build -toolexec 'toolstash -cmp' -a std
  $ GOARCH=mipsle go build -toolexec 'toolstash -cmp' -a std

Updates #42587

Change-Id: Ib5eb99b82310e404cc2d6f0c619b21b8a15406ce
Reviewed-on: https://go-review.googlesource.com/c/go/+/270558
Trust: Alberto Donizetti <alb.donizetti@gmail.com>
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
@golang golang locked and limited conversation to collaborators Nov 17, 2021
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