[0/8] cfg: early CFG simplification

Message

Luc Van Oostenryck Nov. 16, 2020, 10:29 p.m. UTC

This series is a preparatory step for some other optimzations
but is quite valuable in itself. It adds a new phase of CFG
CFG simplification before any other simplifications. To be
effective this pahse needs some other changes:
* phi-sources & phi-nodes must be handled specifically
  whne merinf BBs.
* some missing REPEAT_CFG_CLEANUP must be added
* simplify_memops() must be called unconditionally

These changes slightly decrease the number of 'context imbalance'
warnings (32 less on a total of 995 warnings) and have otherwise a
significant effect on the size of the generated IR (~0.4%).

Luc Van Oostenryck (8):
  testcase: avoid UNDEF
  cfg: add testcase for phi-adjusting during BB merge
  cfg: extract merge_bb() from pack_basic_blocks()
  cfg: adjust phi-sources when merging BBs
  cfg: adjust phi-nodes when merging BBs
  cfg: add missing REPEAT_CFG_CLEANUP
  cfg: call simplify_memops() unconditionally.
  cfg: early CFG simplification

 flow.c                                       | 201 ++++++++++++++++---
 flow.h                                       |   1 +
 linearize.c                                  |   1 +
 memops.c                                     |   2 +
 optimize.c                                   |   9 +-
 simplify.c                                   |   2 +-
 validation/call-inlined.c                    |   4 +
 validation/expand/builtin_constant_inline0.c |   1 +
 validation/inline_base0.c                    |   3 +
 validation/linear/builtin_unreachable0.c     |   4 +-
 validation/linear/builtin_unreachable1.c     |   4 +-
 validation/linear/call-inline.c              |   2 +-
 validation/mem2reg/cond-expr.c               |   4 +-
 validation/mem2reg/cond-expr5.c              |   5 +-
 validation/optim/cse-size.c                  |   5 +-
 validation/optim/memops-missed01.c           |  23 +++
 validation/optim/memops-missed02.c           |  14 ++
 validation/optim/merge_bbe-adjust_phi.c      |  23 +++
 18 files changed, 269 insertions(+), 39 deletions(-)
 create mode 100644 validation/optim/memops-missed01.c
 create mode 100644 validation/optim/memops-missed02.c
 create mode 100644 validation/optim/merge_bbe-adjust_phi.c