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| author | Luc Van Oostenryck <luc.vanoostenryck@gmail.com> | 2020-11-12 22:01:10 +0100 |
|---|---|---|
| committer | Luc Van Oostenryck <luc.vanoostenryck@gmail.com> | 2020-11-17 18:03:24 +0100 |
| commit | 28677f8ac6efd939b2bd306a2b1af0f95ef44136 (patch) | |
| tree | dd406eaa21360a4cd21aa206ccf5bb9f6cf3b298 /validation/mem2reg | |
| parent | 6b5e7cf5ac390f12472f914737c8a947eed0afe0 (diff) | |
| download | sparse-dev-28677f8ac6efd939b2bd306a2b1af0f95ef44136.tar.gz | |
cfg: early CFG simplification
The linearization step sometimes creates a lot of intermediate
basic blocks, often containing just a branch. Their presence often
make things more complicated than needed (more work to do in later
phases, visual clutter when inspection the IR 'by hand') and they
can sometimes, indirectly hinder some optimizations.
Happily, most of them can trivially be optimized away.
So, add a CFG simplification phase running very early and doing:
*) jump threading (eliminate jump to jump)
*) merge single-child/sinle-parents basic blocks.
These changes slightly decrease the number of 'context imbalance'
warnings (32 less on a total of 995 warnings) and the size of
the generated IR (only ~0.4% but this is very significant relatively
to most other simplifications).
They also seem to improve the kernel tests' running time:
before after
real 4m19.261s real 4m17.548s
user 72m03.634s user 71m34.642s
sys 29m05.573s sys 29m01.856s
but it's probably just noise.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Diffstat (limited to 'validation/mem2reg')
| -rw-r--r-- | validation/mem2reg/cond-expr.c | 4 | ||||
| -rw-r--r-- | validation/mem2reg/cond-expr5.c | 5 |
2 files changed, 4 insertions, 5 deletions
diff --git a/validation/mem2reg/cond-expr.c b/validation/mem2reg/cond-expr.c index 8acb00ac..2474d65d 100644 --- a/validation/mem2reg/cond-expr.c +++ b/validation/mem2reg/cond-expr.c @@ -9,6 +9,6 @@ int foo(int a, int b, int c) * check-name: cond-expr * check-command: test-linearize -Wno-decl -fdump-ir=mem2reg $file * check-output-ignore - * check-output-pattern(2): phi\\. - * check-output-pattern(3): phisrc\\. + * check-output-pattern(1): phi\\. + * check-output-pattern(2): phisrc\\. */ diff --git a/validation/mem2reg/cond-expr5.c b/validation/mem2reg/cond-expr5.c index a3ce5e3a..beef8f25 100644 --- a/validation/mem2reg/cond-expr5.c +++ b/validation/mem2reg/cond-expr5.c @@ -15,7 +15,6 @@ int foo(int p, int q, int a) * check-output-ignore * check-output-excludes: load\\. * check-output-excludes: store\\. - * check-output-excludes: phi\\..*, .*, .* - * check-output-pattern(3): phi\\. - * check-output-pattern(5): phisrc\\. + * check-output-pattern(2): phi\\. + * check-output-pattern(4): phisrc\\. */ |