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On 15/01/16 10:07, Richard Biener wrote:
On Fri, Jan 15, 2016 at 10:47 AM, Alan Lawrence <alan.lawrence@arm.com> wrote:On Thu, Jan 14, 2016 at 12:30 PM, Richard Biener <richard.guenther@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
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