cmd/compile: "in prove, detect loops with negative increments" breaks blackfriday tests #26116
Description
CL 104041 (commit 6d379ad) breaks a test in blackfriday:
go test -v github.com/russross/blackfriday/ -run TestReference
=== RUN TestReferenceOverride
--- PASS: TestReferenceOverride (0.02s)
=== RUN TestReferenceLink
--- PASS: TestReferenceLink (0.04s)
=== RUN TestReference
--- FAIL: TestReference (4.82s)
ref_test.go:32:
panic while processing ["## Unordered\n\nAsterisks tight:\n\n*\tasterisk 1\n*\tasterisk 2\n*\tasterisk 3\n\n\nAsterisks loose:\n\n*\tasterisk 1\n\n*\tasterisk 2\n\n*\tasterisk 3\n\n* * "]: block input is missing terminating newline
=== RUN TestReference_EXTENSION_NO_EMPTY_LINE_BEFORE_BLOCK
--- FAIL: TestReference_EXTENSION_NO_EMPTY_LINE_BEFORE_BLOCK (4.80s)
ref_test.go:32:
panic while processing ["## Unordered\n\nAsterisks tight:\n\n*\tasterisk 1\n*\tasterisk 2\n*\tasterisk 3\n\n\nAsterisks loose:\n\n*\tasterisk 1\n\n*\tasterisk 2\n\n*\tasterisk 3\n\n* * "]: block input is missing terminating newline
FAIL
FAIL github.com/russross/blackfriday 9.694s
I haven't looked at all at what exactly is happening, sorry.