On 15/01/16 10:07, Richard Biener wrote:
On Fri, Jan 15, 2016 at 10:47 AM, Alan Lawrence <alan.lawre...@arm.com> wrote:
On Thu, Jan 14, 2016 at 12:30 PM, Richard Biener <richard.guent...@gmail.com>
wrote:
The vuse test is not necessary
+ && (gimple_assign_rhs_code (def) == SSA_NAME
+ || is_gimple_min_invariant (gimple_assign_rhs1 (def))))
and the is_gimple_min_invariant (rhs1) test is not sufficient if you
consider - (-INT_MIN) with -ftrapv for example.
Thanks, I didn't realize gimple_min_invariant would allow such cases.
Well, the invariant would be -INT_MIN but gimple_assign_rhs_code (def) would
be NEGATE_EXPR. Basically you forgot about unary operators.
Hmm, shouldn't those have get_gimple_rhs_class(gimple_assign_rhs_code(stmt)) ==
GIMPLE_UNARY_RHS, rather than GIMPLE_SINGLE_RHS as checked for by
gimple_assign_single_p?
If SINGLE_RHS includes unary operators, the new version of the patch is as
flawed as the previous, in that it drops the unary operator altogether.
--Alan
