Commit Graph

7 Commits

Author SHA1 Message Date
Quentin Colombet 9a8efc08d3 [ShrinkWrapping] Teach shrink-wrapping how to analyze RegMask.
Previously we were conservatively assuming that RegMask operands clobber
callee saved registers.

llvm-svn: 252341
2015-11-06 21:00:13 +00:00
Quentin Colombet b4c6886215 [ShrinkWrap] Refactor the handling of infinite loop in the analysis.
- Strenghten the logic to be sure we hoist the restore point out of the current
  loop. (The fixes a bug with infinite loop, added as part of the patch.)
- Walk over the exit blocks of the current loop to conver to the desired restore
  point in one iteration of the update loop.

llvm-svn: 247958
2015-09-17 23:21:34 +00:00
Quentin Colombet 7b13976254 [ShrinkWrapping] Add a test case for r247710.
llvm-svn: 247713
2015-09-15 18:51:43 +00:00
Cong Hou 03127700d5 Assign weights to edges to jump table / bit test header when lowering switch statement.
Currently, when lowering switch statement and a new basic block is built for jump table / bit test header, the edge to this new block is not assigned with a correct weight. This patch collects the edge weight from all its successors and assign this sum of weights to the edge (and also the other fall-through edge). Test cases are adjusted accordingly.

Differential Revision: http://reviews.llvm.org/D12166#fae6eca7

llvm-svn: 246104
2015-08-26 23:15:32 +00:00
Kit Barton a7bf96ab5c Fix possible infinite loop in shrink wrapping when searching for save/restore
points.

There is an infinite loop that can occur in Shrink Wrapping while searching 
for the Save/Restore points. 

Part of this search checks whether the save/restore points are located in
different loop nests and if so, uses the (post) dominator trees to find the
immediate (post) dominator blocks. However, if the current block does not have
any immediate (post) dominators then this search will result in an infinite
loop. This can occur in code containing an infinite loop.

The modification checks whether the immediate (post) dominator is different from
the current save/restore block. If it is not, then the search terminates and the
current location is not considered as a valid save/restore point for shrink wrapping.

Phabricator: http://reviews.llvm.org/D11607
llvm-svn: 244247
2015-08-06 19:01:57 +00:00
Quentin Colombet 8b984d19f2 [ShrinkWrap][PEI] Do not insert epilogue for unreachable blocks.
Although this is not incorrect to insert such code, it is useless
and it hurts the binary size.

llvm-svn: 241946
2015-07-10 22:09:55 +00:00
Quentin Colombet aa8020752e [X86] Implement the support for shrink-wrapping.
With this patch the x86 backend is now shrink-wrapping capable
and this functionality can be tested by using the
-enable-shrink-wrap switch.

The next step is to make more test and enable shrink-wrapping by
default for x86.

Related to <rdar://problem/20821487>

llvm-svn: 238293
2015-05-27 06:28:41 +00:00