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| author | Simon Marlow <marlowsd@gmail.com> | 2012-10-25 16:18:36 +0100 |
|---|---|---|
| committer | Simon Marlow <marlowsd@gmail.com> | 2012-10-25 16:19:18 +0100 |
| commit | c588395719241c4b5756bd8d60dbf822915dfc5b (patch) | |
| tree | 3741970d0280507a4934d3090ba601cb231ca822 /compiler/cmm | |
| parent | 467e1a623d405440021e92572638be22f0cf5dda (diff) | |
| download | haskell-c588395719241c4b5756bd8d60dbf822915dfc5b.tar.gz | |
Fix a bug in CmmSink exposed by a recent optimisation (#7366)
Diffstat (limited to 'compiler/cmm')
| -rw-r--r-- | compiler/cmm/CmmSink.hs | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/compiler/cmm/CmmSink.hs b/compiler/cmm/CmmSink.hs index 9565fec748..7553e37325 100644 --- a/compiler/cmm/CmmSink.hs +++ b/compiler/cmm/CmmSink.hs @@ -384,6 +384,7 @@ tryToInline dflags live node assigs = go usages node [] assigs -- usages of the regs on the RHS to 2. cannot_inline = skipped `regsUsedIn` rhs -- Note [dependent assignments] + || l `elem` skipped || not (okToInline dflags rhs node) occurs_once = not (l `elemRegSet` live) @@ -415,6 +416,15 @@ tryToInline dflags live node assigs = go usages node [] assigs -- -- For now we do nothing, because this would require putting -- everything inside UniqSM. +-- +-- One more variant of this (#7366): +-- +-- [ y = e, y = z ] +-- +-- If we don't want to inline y = e, because y is used many times, we +-- might still be tempted to inline y = z (because we always inline +-- trivial rhs's). But of course we can't, because y is equal to e, +-- not z. addUsage :: UniqFM Int -> LocalReg -> UniqFM Int addUsage m r = addToUFM_C (+) m r 1 |