Opened 4 years ago

Last modified 4 months ago

#8657 new bug

-fregs-graph still has a limit on spill slots

Reported by: simonmar Owned by: archblob
Priority: normal Milestone:
Component: Compiler (NCG) Version: 7.7
Keywords: Cc: simonmar, tjakway
Operating System: Unknown/Multiple Architecture: Unknown/Multiple
Type of failure: Compile-time crash Test Case:
Blocked By: Blocking:
Related Tickets: #7679 Differential Rev(s):
Wiki Page:

Description

The limit on spill slots was removed for the linear register allocator in 7.8, but not for -fregs-graph.

SHA-1 fails to compile with -fregs-graph in 7.8.

Related: #7679 (-fregs-graph generates poor code with the new codegen).

Change History (15)

comment:1 Changed 4 years ago by simonmar

comment:2 Changed 4 years ago by simonmar

comment:3 Changed 4 years ago by simonmar

Priority: normalhighest

For 7.8.1 we should probably disable -fregs-graph

comment:4 Changed 4 years ago by schyler

Could it be ninja-fixed before 7.8.1? :/

comment:5 Changed 4 years ago by Simon Marlow <marlowsd@…>

In f0a7261a39bd1a8c5217fecba56c593c353f198c/ghc:

Disable -fregs-graph (#7679, #8657)

comment:6 Changed 4 years ago by simonmar

Milestone: 7.8.17.10.1
Priority: highestnormal

comment:7 Changed 3 years ago by archblob

Owner: set to archblob

I'll be working on this, should be easy once I understand the code.

comment:8 Changed 3 years ago by thoughtpolice

Milestone: 7.10.17.12.1

Moving to 7.12.1 milestone; if you feel this is an error and should be addressed sooner, please move it back to the 7.10.1 milestone.

comment:9 Changed 2 years ago by thoughtpolice

Milestone: 7.12.18.0.1

Milestone renamed

comment:10 Changed 20 months ago by thomie

Milestone: 8.0.1

comment:11 Changed 15 months ago by bgamari

For the record, I believe the spill slot limit was fixed in the linear allocator in 0b0a41f96cbdaf52aac171c9c58459e3187b0f46.

comment:12 Changed 15 months ago by Ben Gamari <ben@…>

In 6a5d13c4/ghc:

nativeGen: Allow -fregs-graph to be used

Previously the flag was silently ignored due the #7679 and #8657. This,
however, seems unnecessarily brutal and makes experimentation unduly
difficult for users.

Test Plan: Validate

Reviewers: austin, simonmar

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2335

GHC Trac Issues: #7679, #8657

comment:13 Changed 8 months ago by tjakway

Cc: tjakway added

comment:14 Changed 4 months ago by dfeuer

bgamari, can we close this ticket? The performance issue remains open as #7679.

comment:15 Changed 4 months ago by bgamari

I don't believe so, the limit is still present in the graph coloring allocator.

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