cmd/compile: invalid instruction: MOVL $11553462026240, AX #41711

ALTree · 2020-09-30T13:47:01Z

Filed on behalf of Jan Mercl (from a golang-dev thread).

What version of Go are you using (`go version`)?

$ go version
go version go1.15.2 linux/amd64

Does this issue reproduce with the latest release?

Yes.

What operating system and processor architecture are you using (`go env`)?

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/jnml/.cache/go-build"
GOENV="/home/jnml/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/jnml/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/jnml"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/home/jnml/src/go.googlesource.com/go/goroot"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/home/jnml/src/go.googlesource.com/go/goroot/pkg/tool/linux_amd64"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build571607678=/tmp/go-build -gno-record-gcc-switches"

What did you do?

jnml@e5-1650:~/tmp/csmith$ cat main.go
package foo

import "modernc.org/libc"

func safe_div_func_int16_t_s_s(tls *libc.TLS, si1 int16, si2 int16) int16 {
        if (int32(si2) == 0) || ((int32(si1) == (-32767 - 1)) && (int32(si2) == (-1))) {
                return si1
        }
        return (int16(int32(si1) / int32(si2)))
}

func safe_lshift_func_int16_t_s_u(tls *libc.TLS, left int16, right uint32) int16 {
        if ((int32(left) < 0) || ((right) >= uint32(32))) || (int32(left) > (int32((32767)) >> (right))) {
                return left
        }
        return (int16(int32(left) << (right)))
}

func safe_sub_func_int32_t_s_s(tls *libc.TLS, si1 int32, si2 int32) int32 {
        if ((si1 ^ si2) & (((si1 ^ ((si1 ^ si2) & (^int32(libc.Int32FromInt32(2147483647))))) - si2) ^ si2)) < 0 {
                return si1
        }
        return (si1 - si2)
}

func safe_unary_minus_func_int64_t_s(tls *libc.TLS, si int64) int64 {
        if si == (-9223372036854775807 - int64(1)) {
                return si
        }
        return -si
}

func safe_sub_func_uint16_t_u_u(tls *libc.TLS, ui1 uint16, ui2 uint16) uint16 {
        return (uint16(int32(ui1) - int32(ui2)))
}

func func_44(tls *libc.TLS) uint16 {
        return safe_sub_func_uint16_t_u_u(tls, (uint16((int32(safe_div_func_int16_t_s_s(tls, 0, int16(safe_sub_func_int32_t_s_s(tls, 1, int32(safe_lshift_func_int16_t_s_u(tls, int16(0x1504), uint32(safe_unary_minus_func_int64_t_s(tls, int64(libc.Bool32(true))))))))))))), 0)
}
jnml@e5-1650:~/tmp/csmith$ go build main.go

What did you expect to see?

Nothing but a command prompt.

What did you see instead?

# command-line-arguments
./main.go:38:2: invalid instruction: 00105 (/home/jnml/tmp/csmith/main.go:38)   MOVL    $11553462026240, AX
jnml@e5-1650:~/tmp/csmith$

The text was updated successfully, but these errors were encountered:

ALTree · 2020-09-30T13:53:42Z

cc @randall77

dr2chase · 2020-09-30T14:26:36Z

I'm trying to reproduce, this has the look and feel of a bug I thought I could create on MIPS, that I (also) encountered with late call expansion. Basically, if you can smuggle a funny constant past the early phases and have it appear "late" (e.g., within late call expansion, which is not in this compiler yet, or in prove, which is), surprising things can happen. I solved it for MIPS by adding some code generation rules, but I don't see the same missing rules on AMD64 so it is not an exact duplicate.

dr2chase · 2020-09-30T15:09:31Z

No, it's weirder than that. Compare compilation of the two MOVLconst <int32> [0] : AX in the code:

b28: ← b16-
v24 (9) = MOVLconst <int32> [0] : AX
v102 (+9) = DIVL <int32,int32> [false] v24 v85 : <AX,DX>
v106 (+9) = Select0 <int32> v102 : AX
Plain → b30 (+38)
b10: ← b8-
v43 (13) = MOVLconst <int32> [32767] : CX
v42 (13) = SARLconst <int32> [31] v43 : CX
v20 (13) = CMPLconst <flags> [5380] v42
LT v20 → b13 b12 (13)
b12: ← b10-
v105 (16) = MOVLconst <int32> [0] : AX
Plain → b16 (+38)


v42   00030 (+9) XORL AX, AX
v102  00031 (9) CMPL CX, $-1
v102  00032 (9) JEQ 36
v102  00033 (9) CDQ
v102  00034 (9) IDIVL CX
v102  00035 (9) JMP 38
v102  00036 (9) NEGL AX
v102  00037 (9) XORL DX, DX
b28   00038 (+38) JMP 28
v43   00039 (13) MOVL $32767, CX
v42   00040 (13) SARL $31, CX
v20   00041 (13) CMPL CX, $5380
b10   00042 (13) JLT 8
v105  00043 (16) MOVL $11553462026240, AX
b12   00044 (+38) JMP 9

I've got other things to work on, just wanted to be sure that wasn't a variant of the bug I fixed just the other day for MIPS.

sam3000 · 2020-09-30T19:55:42Z

FWIW, a slightly more contained repro - no imports and simplied where possible:
https://play.golang.org/p/rB2HvJwS5j3

mundaym · 2020-09-30T21:08:43Z

v105 (16) = MOVLconst <int32> [0] : AX
v105  00043 (16) MOVL $11553462026240, AX

This looks to me like a rule isn't sign extending an int32 constant to 64 bits. The pretty printer will just ignore the high bits but the MOVL will get a copy of the raw int64 value. I bet the new typed rules in master will fix it.

I got curious and took a quick look at the AMD64 rules in Go 1.15. This looks like the sort of rule that could cause an issue like this:

go/src/cmd/compile/internal/ssa/gen/AMD64.rules

Line 1457 in fa01c8a

(SHLLconst [d] (MOVLconst [c])) -> (MOVLconst [int64(int32(c)) << uint64(d)])

(The sign extension to 64-bits happens before the shift and not after, so the resulting value could be out-of-range for an int32. This particular rule probably doesn't trigger very often because the generic rules do most constant folding.)

randall77 · 2020-09-30T21:11:05Z

A MOVLconst that doesn't have its high bits sign-extended correctly should fail if the check pass is enabled. Does it?

mundaym · 2020-09-30T21:29:37Z

Yep (based on #41711 (comment)).

$ ./go1.15/bin/go tool compile -d=ssa/check/on example.go 
example.go:37:35: internal compiler error: 'func_44': bad int32 AuxInt value for v43

Please file a bug report including a short program that triggers the error.
https://golang.org/issue/new

randall77 · 2020-09-30T21:33:59Z

@gopherbot please open a backport issue for 1.15.

randall77 · 2020-09-30T21:34:13Z

Seems to be ok for 1.14 and earlier.

gopherbot · 2020-09-30T21:34:16Z

Backport issue(s) opened: #41720 (for 1.15).

Remember to create the cherry-pick CL(s) as soon as the patch is submitted to master, according to https://golang.org/wiki/MinorReleases.

randall77 · 2020-09-30T21:35:37Z

Also ok at tip. Just 1.15 needs fixing.

gopherbot · 2020-10-01T17:01:16Z

Change https://golang.org/cl/258817 mentions this issue: [release-branch.go1.15] cmd/compile: fix left shift constant folding rule

…rule The 32-bit left shift constant folding rule should keep its result properly sign extended. Fixes #41720 Fixes #41711 Change-Id: I0fc74444d444274e911952e1725dab0b7737a846 Reviewed-on: https://go-review.googlesource.com/c/go/+/258817 Trust: Keith Randall <khr@golang.org> Run-TryBot: Keith Randall <khr@golang.org> Reviewed-by: David Chase <drchase@google.com> TryBot-Result: Go Bot <gobot@golang.org>

aclements · 2020-10-15T18:09:59Z

@randall77 , is it okay to close this issue now that the 1.15 CL is in?

randall77 · 2020-10-15T18:12:42Z

Yes.

…rule The 32-bit left shift constant folding rule should keep its result properly sign extended. Fixes golang#41720 Fixes golang#41711 Change-Id: I0fc74444d444274e911952e1725dab0b7737a846 Reviewed-on: https://go-review.googlesource.com/c/go/+/258817 Trust: Keith Randall <khr@golang.org> Run-TryBot: Keith Randall <khr@golang.org> Reviewed-by: David Chase <drchase@google.com> TryBot-Result: Go Bot <gobot@golang.org>

ALTree added the NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one. label Sep 30, 2020

ALTree added this to the Go1.16 milestone Sep 30, 2020

randall77 added release-blocker NeedsFix The path to resolution is known, but the work has not been done. and removed NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one. labels Sep 30, 2020

gopherbot mentioned this issue Sep 30, 2020

cmd/compile: invalid instruction: MOVL $11553462026240, AX [1.15 backport] #41720

Closed

randall77 closed this as completed Oct 15, 2020

randall77 mentioned this issue Nov 20, 2020

cmd/compile: ICE due to bad ORL constant [1.15] #42753

Closed

golang locked and limited conversation to collaborators Oct 15, 2021

gopherbot added the FrozenDueToAge label Oct 15, 2021

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cmd/compile: invalid instruction: MOVL $11553462026240, AX #41711

cmd/compile: invalid instruction: MOVL $11553462026240, AX #41711

ALTree commented Sep 30, 2020 •

edited

ALTree commented Sep 30, 2020

dr2chase commented Sep 30, 2020 •

edited

dr2chase commented Sep 30, 2020 •

edited

sam3000 commented Sep 30, 2020

mundaym commented Sep 30, 2020 •

edited

randall77 commented Sep 30, 2020

mundaym commented Sep 30, 2020

randall77 commented Sep 30, 2020

randall77 commented Sep 30, 2020

gopherbot commented Sep 30, 2020

randall77 commented Sep 30, 2020

gopherbot commented Oct 1, 2020

aclements commented Oct 15, 2020

randall77 commented Oct 15, 2020

cmd/compile: invalid instruction: MOVL $11553462026240, AX #41711

cmd/compile: invalid instruction: MOVL $11553462026240, AX #41711

Comments

ALTree commented Sep 30, 2020 • edited

What version of Go are you using (go version)?

Does this issue reproduce with the latest release?

What operating system and processor architecture are you using (go env)?

What did you do?

What did you expect to see?

What did you see instead?

ALTree commented Sep 30, 2020

dr2chase commented Sep 30, 2020 • edited

dr2chase commented Sep 30, 2020 • edited

sam3000 commented Sep 30, 2020

mundaym commented Sep 30, 2020 • edited

randall77 commented Sep 30, 2020

mundaym commented Sep 30, 2020

randall77 commented Sep 30, 2020

randall77 commented Sep 30, 2020

gopherbot commented Sep 30, 2020

randall77 commented Sep 30, 2020

gopherbot commented Oct 1, 2020

aclements commented Oct 15, 2020

randall77 commented Oct 15, 2020

ALTree commented Sep 30, 2020 •

edited

What version of Go are you using (`go version`)?

What operating system and processor architecture are you using (`go env`)?

dr2chase commented Sep 30, 2020 •

edited

dr2chase commented Sep 30, 2020 •

edited

mundaym commented Sep 30, 2020 •

edited