cmd/compile: irgen uses wrong dict param to generate code for getting dict type

[mdempsky]

Since submitting https://go-review.googlesource.com/c/go/+/388534, the linux-amd64-noopt builder is failing in test/typeparam/mdempsky/13.go:

https://build.golang.org/log/e4383af359722053b9d212fc3c8c69351e0ffbd1

##### ../test
# go run run.go typeparam/mdempsky/13.go
exit status 2
# command-line-arguments
typeparam/mdempsky/13.go:38:3: internal compiler error: 'G[go.shape.interface { Abs() "".MyInt }_0,go.shape.int_1].func1': addr of undeclared ONAME .dict. declared: map[a0:v5 r0:v6 .dict:v4]

I'm not immediately able to reproduce this failure locally.

/cc @danscales @randall77

[mdempsky]

Oh, I forgot the noopt builder uses -N -l, not just -N.

This is repro'able with go run -gcflags="-N -l" test/typeparam/mdempsky/13.go.

A slightly different failure message occurs with -gcflags=-l instead:

# command-line-arguments
./13.go:38:3: internal compiler error: 'G[go.shape.interface { Abs() "".MyInt }_0,go.shape.int_1].func1': Value live at entry. It shouldn't be. func G[go.shape.interface { Abs() "".MyInt }_0,go.shape.int_1].func1, node .dict, value nil

[gopherbot]

Change https://go.dev/cl/388894 mentions this issue: test: workaround codegen bug in typeparam/mdempsky/13.go

[gopherbot]

Change https://go.dev/cl/391994 mentions this issue: cmd/compile: fix wrong dict param when getting dict type

[cuonglm]

It seems to me this issue should be cherry pick to 1.18 branch

cc @randall77 @danscales @mdempsky

[mdempsky]

I think so too. Otherwise delve will have issues debugging generic code, right?

[cuonglm]

I think so too. Otherwise delve will have issues debugging generic code, right?

Yeah, indeed. delve is the biggest user of -gcflags="-N -l"

[cuonglm]

Reopening for backport to 1.18 release branch.