cmd/compile: infinite loop in the inliner

[randall77]

git clone https://gitlab.com/cznic/libsamplerate
cd libsamplerate
GOARCH=amd64 ~/go1.24.2/bin/go build

A sample of the infinite loop it appears to be in:

  * frame #0: 0x00000001006e7a34 compile`cmd/compile/internal/ir.(*CallExpr).doChildren + 52
    frame #1: 0x0000000100703d78 compile`cmd/compile/internal/ir.Any.func1 + 104
    frame #2: 0x00000001006f6934 compile`cmd/compile/internal/ir.(*ParenExpr).doChildren + 180
    frame #3: 0x0000000100703d78 compile`cmd/compile/internal/ir.Any.func1 + 104
    frame #4: 0x00000001007005b4 compile`cmd/compile/internal/ir.(*UnaryExpr).doChildren + 180
    frame #5: 0x0000000100703d78 compile`cmd/compile/internal/ir.Any.func1 + 104
    frame #6: 0x00000001006eb8e4 compile`cmd/compile/internal/ir.(*ConvExpr).doChildren + 180
    frame #7: 0x0000000100703d78 compile`cmd/compile/internal/ir.Any.func1 + 104
    frame #8: 0x00000001006f3b10 compile`cmd/compile/internal/ir.(*KeyExpr).doChildren + 224
    frame #9: 0x0000000100703d78 compile`cmd/compile/internal/ir.Any.func1 + 104
    frame #10: 0x00000001006eae10 compile`cmd/compile/internal/ir.(*CompLitExpr).doChildren + 224
    frame #11: 0x0000000100703d78 compile`cmd/compile/internal/ir.Any.func1 + 104
    frame #12: 0x00000001006fdb94 compile`cmd/compile/internal/ir.(*StructKeyExpr).doChildren + 180
    frame #13: 0x0000000100703d78 compile`cmd/compile/internal/ir.Any.func1 + 104
    frame #14: 0x00000001006eae10 compile`cmd/compile/internal/ir.(*CompLitExpr).doChildren + 224
    frame #15: 0x0000000100703d78 compile`cmd/compile/internal/ir.Any.func1 + 104
    frame #16: 0x00000001006e5270 compile`cmd/compile/internal/ir.(*AssignStmt).doChildren + 224
    frame #17: 0x0000000100703d78 compile`cmd/compile/internal/ir.Any.func1 + 104
    frame #18: 0x00000001006dd834 compile`cmd/compile/internal/ir.(*Func).doChildren + 100
    frame #19: 0x0000000100703d78 compile`cmd/compile/internal/ir.Any.func1 + 104
    frame #20: 0x0000000100703cd0 compile`cmd/compile/internal/ir.Any + 176
    frame #21: 0x0000000100b83348 compile`cmd/compile/internal/inline.canInlineCallExpr + 2648
    frame #22: 0x0000000100b83ea4 compile`cmd/compile/internal/inline.mkinlcall + 52
    frame #23: 0x0000000100b81e98 compile`cmd/compile/internal/inline.TryInlineCall + 296
    frame #24: 0x0000000100c6acf0 compile`cmd/compile/internal/inline/interleaved.(*inlClosureState).edit + 144
    frame #25: 0x0000000100d72b58 compile`cmd/compile/internal/gc.Main.DevirtualizeAndInlinePackage.func2.1 + 152
    frame #26: 0x00000001006de3a4 compile`cmd/compile/internal/ir.WithFunc + 148
    frame #27: 0x0000000100d72a58 compile`cmd/compile/internal/gc.Main.DevirtualizeAndInlinePackage.func2 + 392
    frame #28: 0x0000000100701e80 compile`cmd/compile/internal/ir.(*bottomUpVisitor).visit + 880
    frame #29: 0x0000000100701ad4 compile`cmd/compile/internal/ir.VisitFuncsBottomUp + 196
    frame #30: 0x0000000100d711c4 compile`cmd/compile/internal/gc.Main + 4484
    frame #31: 0x0000000100d98650 compile`main.main + 272
    frame #32: 0x0000000100533844 compile`runtime.main + 644

[randall77]

@golang/compiler
@dr2chase Want to take a look?

[dmitshur]

We'll need to create a backport candidate issue for the Go1.24.3 milestone; moving this to Go1.25.

[gabyhelp]

Related Issues

• cmd/compile: infinite loop in types2 #48136 (closed)
• cmd/compile crash with -l=4 #44430 (closed)
• cmd/compile: infinite loop #48135 (closed)
• cmd/compile: infinite loop in -G=3 type instantiation #48030 (closed)
• cmd/compile: internal compiler error: cannot inline function containing closure #19705 (closed)
• cmd/compile: compiler crash on valid code #11040 (closed)
• cmd/compile: bug in cmd/compile/internal/inline/interleaved.fixpoint.func2 #71002
• cmd/compile: internal compiler error: missing import reader for sync.(*RWMutex).RLock #48454 (closed)
• cmd/compile: panic while compiling empty package in a loop #16726 (closed)
• cmd/compile: compiler crashes with a 10MB error message when building tiny program on -c=4 #20162 (closed)

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[dr2chase]

Tip looked fine (this was GOARCH=amd64 on Darwin).

But I checked it at the current tip of go1.24 (which is a hair past 1.24.2) and am currently 5 cpu minutes in on one compile in the build but at a stable 540MB of memory consumption. Dumping stacks from with the Apple profiler indeed suggests something in the inliner.

So perhaps we fixed it, but where/how?

[dr2chase]

Well that was obvious (in highsight) cmd/compile: remove no-longer-necessary recursive inlining checks. The plan was to split the change into two parts so as to make it easier to backport. Mice, men, etc, oops.

[gopherbot]

Change https://go.dev/cl/666555 mentions this issue: [release-branch.go1.24] cmd/compile: remove no-longer-necessary recursive inlining checks

[prattmic]

Just to clarify, are you saying this was a regression in https://go.dev/cl/655155 (also backported in https://go.dev/cl/657075) which is fixed in https://go.dev/cl/655157?

[dr2chase]

I didn't test it before https://go.dev/cl/655155 so I'm not sure it is a regression in that CL. It is a regression in one of the 1.24 inliner CLs, for sure.

[dr2chase]

@gopherbot, please open a backport issue for 1.24. This is a serious compiler bug and a regression in 1.24.