[UpdateLLCTestChecks] Pick the correct output block when generating isel debug output checks in update_llc_test_checks.py

[ningxinr]

Summary

This change is a follow-up change of D119368. This change picks up the right block
from the generated isel debug output, and make the generated tests runnable.

With this change, the checks generated will pass. A lit tests of Lanai is added to
demonstrate what a passing test would look like.

This patch concludes the support of instruction selection debug output check generation.

[Flakebi]

Just to check that I understand this correctly.
Is the intention behind the function prefix to make it configurable in the end, so that one can also check for Legalized selection DAG and others?

Or is it only to pick the right block, without making it configurable?
Then I think it would be easier to use check_label_format = '{} %s-LABEL: Selected selection DAG:{{.*}}%s%s:', which does not need any changes in common.py

llvm/utils/UpdateTestChecks/common.py

844–846 ↗

(On Diff #419441)

This might be easier to read?

func_prefix = func_dict[checkprefix][func_name].func_prefix
if func_prefix:
  output_lines.append(check_label_format % (checkprefix, func_prefix + '{{.*}}', func_name, args_and_sig))

[ningxinr]

In D122824#3421553, @Flakebi wrote:

Just to check that I understand this correctly.
Is the intention behind the function prefix to make it configurable in the end, so that one can also check for Legalized selection DAG and others?

Or is it only to pick the right block, without making it configurable?
Then I think it would be easier to use check_label_format = '{} %s-LABEL: Selected selection DAG:{{.*}}%s%s:', which does not need any changes in common.py

You were right, this is much easier for my purpose. For this use case the function prefix is an invariant of function name and FileCheck prefixes, so we can just add it to the check_label_format. I suppose we could always change this later when the need of making it configurable rises.

Thank you, Sebastian! :)

[ningxinr]

Update commit message to reflect the feedback

[Flakebi]

llvm/utils/UpdateTestChecks/isel.py

16

I guess this TODO is fixed with this patch?

18

For consistency with the checked string below, maybe use spaces here for Selected selection DAG: %bb.0?

[lebedev.ri]

This review may be stuck/dead, consider abandoning if no longer relevant.
Removing myself as reviewer in attempt to clean dashboard.