Hi Jakub,
On 10/08/16 07:46, Jakub Jelinek wrote:
On Wed, Aug 10, 2016 at 07:42:25AM +1000, kugan wrote:
There was no new regression while testing. I also moved the testcase from
gcc.dg/torture/pr72835.c to gcc.dg/tree-ssa/pr72835.c. Is this OK for trunk?
This looks strange. The tree-ssa-reassoc.c code has been trying to never
reuse SSA_NAMEs if they would hold a different value.
So there should be no resetting of flow sensitive info needed.
We are not reusing but, if you see the example change in reassoc:
- _5 = -_4;
- _6 = _2 * _5;
+ _5 = _4;
+ _6 = _5 * _2;
_5 and _6 will now have different value ranges because they compute
different values. Therefore I think we should reset (?).
Thanks,
Kugan
gcc/testsuite/ChangeLog:
2016-08-10 Kugan Vivekanandarajah <kug...@linaro.org>
PR tree-optimization/72835
* gcc.dg/tree-ssa/pr72835.c: New test.
gcc/ChangeLog:
2016-08-10 Kugan Vivekanandarajah <kug...@linaro.org>
PR tree-optimization/72835
* tree-ssa-reassoc.c (rewrite_expr_tree): Reset value_range of LHS when
operands are changed.
(rewrite_expr_tree_parallel): Likewise.
Jakub
