From ab63daac0e0ed8749514e38d714cfcd4562f4326 Mon Sep 17 00:00:00 2001
From: Krzysztof Gogolewski <krzysztof.gogolewski@tweag.io>
Date: Fri, 21 Apr 2023 11:37:42 +0200
Subject: [PATCH] Allow Core optimizations when interpreting bytecode
Tracking ticket: #23056
MR: !10399
This adds the flag `-funoptimized-core-for-interpreter`, permitting use
of the `-O` flag to enable optimizations when compiling with the
interpreter backend, like in ghci.
---
compiler/GHC/Driver/Flags.hs | 1 +
compiler/GHC/Driver/Session.hs | 5 +++-
docs/users_guide/debugging.rst | 14 +++++++++++
testsuite/driver/testlib.py | 2 +-
.../tests/simplCore/should_compile/T23267.hs | 25 +++++++++++++++++++
.../simplCore/should_compile/T23267.script | 1 +
.../tests/simplCore/should_compile/all.T | 1 +
.../tests/simplCore/should_run/T23056.hs | 10 ++++++++
.../tests/simplCore/should_run/T23056.script | 2 ++
.../tests/simplCore/should_run/T23056.stdout | 1 +
testsuite/tests/simplCore/should_run/all.T | 1 +
11 files changed, 61 insertions(+), 2 deletions(-)
create mode 100644 testsuite/tests/simplCore/should_compile/T23267.hs
create mode 100644 testsuite/tests/simplCore/should_compile/T23267.script
create mode 100644 testsuite/tests/simplCore/should_run/T23056.hs
create mode 100644 testsuite/tests/simplCore/should_run/T23056.script
create mode 100644 testsuite/tests/simplCore/should_run/T23056.stdout
diff --git a/compiler/GHC/Driver/Flags.hs b/compiler/GHC/Driver/Flags.hs
index 3496b2af5aaa..2099d7c10037 100644
--- a/compiler/GHC/Driver/Flags.hs
+++ b/compiler/GHC/Driver/Flags.hs
@@ -387,6 +387,7 @@ data GeneralFlag
| Opt_KeepGoing
| Opt_ByteCode
| Opt_ByteCodeAndObjectCode
+ | Opt_UnoptimizedCoreForInterpreter
| Opt_LinkRts
-- output style opts
diff --git a/compiler/GHC/Driver/Session.hs b/compiler/GHC/Driver/Session.hs
index 52361abb09bd..84962f786879 100644
--- a/compiler/GHC/Driver/Session.hs
+++ b/compiler/GHC/Driver/Session.hs
@@ -3573,6 +3573,7 @@ fFlagsDeps = [
flagSpec "write-ide-info" Opt_WriteHie,
flagSpec "unbox-small-strict-fields" Opt_UnboxSmallStrictFields,
flagSpec "unbox-strict-fields" Opt_UnboxStrictFields,
+ flagSpec "unoptimized-core-for-interpreter" Opt_UnoptimizedCoreForInterpreter,
flagSpec "version-macros" Opt_VersionMacros,
flagSpec "worker-wrapper" Opt_WorkerWrapper,
flagSpec "worker-wrapper-cbv" Opt_WorkerWrapperUnlift, -- See Note [Worker/wrapper for strict arguments]
@@ -3896,7 +3897,8 @@ defaultFlags settings
Opt_DumpWithWays,
Opt_CompactUnwind,
Opt_ShowErrorContext,
- Opt_SuppressStgReps
+ Opt_SuppressStgReps,
+ Opt_UnoptimizedCoreForInterpreter
]
++ [f | (ns,f) <- optLevelFlags, 0 `elem` ns]
@@ -4976,6 +4978,7 @@ makeDynFlagsConsistent dflags
"Enabling -fPIC as it is always on for this platform"
| backendForcesOptimization0 (backend dflags)
+ , gopt Opt_UnoptimizedCoreForInterpreter dflags
, let (dflags', changed) = updOptLevelChanged 0 dflags
, changed
= loop dflags' ("Optimization flags are incompatible with the " ++
diff --git a/docs/users_guide/debugging.rst b/docs/users_guide/debugging.rst
index e2acac340f23..04bb5ca97a18 100644
--- a/docs/users_guide/debugging.rst
+++ b/docs/users_guide/debugging.rst
@@ -1146,3 +1146,17 @@ Other
be terminated. This helps narrowing down if an issue is due to tag inference
if things go wrong. Which would otherwise be quite difficult.
+.. ghc-flag:: -funoptimized-core-for-interpreter
+ :shortdesc: Disable optimizations with the interpreter
+ :reverse: -fno-unoptimized-core-for-interpreter
+ :type: dynamic
+
+ :since: 9.8.1
+
+ default: enabled
+
+ At the moment, ghci disables optimizations, because not all passes
+ are compatible with the interpreter.
+ This option can be used to override this check, e.g.
+ ``ghci -O2 -fno-unoptimized-core-for-interpreter``.
+ It is not recommended for normal use and can cause a compiler panic.
diff --git a/testsuite/driver/testlib.py b/testsuite/driver/testlib.py
index 09ab06d469cf..b2353531c249 100644
--- a/testsuite/driver/testlib.py
+++ b/testsuite/driver/testlib.py
@@ -387,7 +387,7 @@ def expect_fail_for( ways: List[WayName] ):
def expect_broken( bug: IssueNumber ):
"""
- This test is a expected not to work due to the indicated issue number.
+ This test is expected not to work due to the indicated issue number.
"""
def helper( name: TestName, opts ):
record_broken(name, opts, bug)
diff --git a/testsuite/tests/simplCore/should_compile/T23267.hs b/testsuite/tests/simplCore/should_compile/T23267.hs
new file mode 100644
index 000000000000..02307cea5da4
--- /dev/null
+++ b/testsuite/tests/simplCore/should_compile/T23267.hs
@@ -0,0 +1,25 @@
+module T23267 where
+
+data N = Z | S N
+
+union :: N -> ()
+union Z = ()
+union t = splitS t
+
+splitS :: N -> ()
+splitS Z = ()
+splitS (S l) = splitS l
+
+{- Results in this error:
+
+*** Core Lint errors : in result of SpecConstr ***
+T23267.hs:10:1: warning:
+ Out of scope: l_aBE :: N
+ [LclId]
+ In the RHS of $ssplitS_sJx :: N -> ()
+ In the body of lambda with binder sc_sJw :: N
+ Substitution: <InScope = {}
+ IdSubst = []
+ TvSubst = []
+ CvSubst = []>
+-}
diff --git a/testsuite/tests/simplCore/should_compile/T23267.script b/testsuite/tests/simplCore/should_compile/T23267.script
new file mode 100644
index 000000000000..75e8cf5aaf49
--- /dev/null
+++ b/testsuite/tests/simplCore/should_compile/T23267.script
@@ -0,0 +1 @@
+:load T23267
diff --git a/testsuite/tests/simplCore/should_compile/all.T b/testsuite/tests/simplCore/should_compile/all.T
index 90e67d81fe35..ae48423fa06d 100644
--- a/testsuite/tests/simplCore/should_compile/all.T
+++ b/testsuite/tests/simplCore/should_compile/all.T
@@ -477,3 +477,4 @@ test('T23012', normal, compile, ['-O'])
test('RewriteHigherOrderPatterns', normal, compile, ['-O -ddump-rule-rewrites -dsuppress-all -dsuppress-uniques'])
test('T23024', normal, multimod_compile, ['T23024', '-O -v0'])
test('T23026', normal, compile, ['-O'])
+test('T23267', [expect_broken(23267), only_ways(['ghci']), extra_hc_opts('-fno-unoptimized-core-for-interpreter -fspec-constr')], ghci_script, ['T23267.script'])
diff --git a/testsuite/tests/simplCore/should_run/T23056.hs b/testsuite/tests/simplCore/should_run/T23056.hs
new file mode 100644
index 000000000000..abf3d7a7be9c
--- /dev/null
+++ b/testsuite/tests/simplCore/should_run/T23056.hs
@@ -0,0 +1,10 @@
+module Main where
+
+fun :: IO ()
+fun = pure ()
+{-# noinline fun #-}
+
+{-# rules "fun" fun = putStrLn "fun" #-}
+
+main :: IO ()
+main = fun
diff --git a/testsuite/tests/simplCore/should_run/T23056.script b/testsuite/tests/simplCore/should_run/T23056.script
new file mode 100644
index 000000000000..fdf0d3b7220f
--- /dev/null
+++ b/testsuite/tests/simplCore/should_run/T23056.script
@@ -0,0 +1,2 @@
+:load T23056
+main
diff --git a/testsuite/tests/simplCore/should_run/T23056.stdout b/testsuite/tests/simplCore/should_run/T23056.stdout
new file mode 100644
index 000000000000..3df46ad19028
--- /dev/null
+++ b/testsuite/tests/simplCore/should_run/T23056.stdout
@@ -0,0 +1 @@
+fun
diff --git a/testsuite/tests/simplCore/should_run/all.T b/testsuite/tests/simplCore/should_run/all.T
index 7348e1015a53..bfd5fa62610d 100644
--- a/testsuite/tests/simplCore/should_run/all.T
+++ b/testsuite/tests/simplCore/should_run/all.T
@@ -112,3 +112,4 @@ test('T22998', normal, compile_and_run, ['-O0 -fspecialise -dcore-lint'])
test('T23184', normal, compile_and_run, ['-O'])
test('T23134', normal, compile_and_run, ['-O0 -fcatch-nonexhaustive-cases'])
test('T23289', normal, compile_and_run, [''])
+test('T23056', [only_ways(['ghci']), extra_hc_opts('-fno-unoptimized-core-for-interpreter -O')], ghci_script, ['T23056.script'])
--
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