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| author | David Terei <davidterei@gmail.com> | 2012-01-12 15:43:12 -0800 |
|---|---|---|
| committer | David Terei <davidterei@gmail.com> | 2012-01-12 16:42:07 -0800 |
| commit | 4ef5ce6f463ae1ffc6afc1f50a99ecf226bcbf1b (patch) | |
| tree | c7396dd00c768ada5dbe14beaca3a4786ce0453d /docs | |
| parent | 167d2d42f02e4e2a7bbbe02f584b289d6a39ee37 (diff) | |
| download | haskell-4ef5ce6f463ae1ffc6afc1f50a99ecf226bcbf1b.tar.gz | |
Add '-freg-liveness' flag to control if STG liveness information
is used for optimisation. (enabled by default)
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/users_guide/flags.xml | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/docs/users_guide/flags.xml b/docs/users_guide/flags.xml index 10679576ef..8e599c26ae 100644 --- a/docs/users_guide/flags.xml +++ b/docs/users_guide/flags.xml @@ -1608,6 +1608,23 @@ </row> <row> + <entry><option>-freg-liveness</option></entry> + <entry>Track STG register liveness to avoid saving and restoring + dead registers, as well as freeing the dead ones for use in + intermediate code. (LLVM backend only). + + Traditionally GHC has reserved a set of machine registers for the + exclusive use of storing a stack pointer, heap pointer and + general purpose function argument registers (these are the so + called STG registers). This optimisation tracks the liveness of + the machine registers the STG registers are mapped to so that the + machine register can be used for other purposes when the STG + register are dead.</entry> + <entry>dynamic</entry> + <entry><option>-fno-reg-liveness</option></entry> + </row> + + <row> <entry><option>-fsimplifier-phases</option></entry> <entry>Set the number of phases for the simplifier (default 2). Ignored with <option>-O0</option>.</entry> |