Re: [PATCH] Improve handling of unknown sign bit in CCP.

2021-08-09 Thread Richard Biener via Gcc-patches
On Sun, Aug 8, 2021 at 12:43 PM Roger Sayle wrote: > > > This middle-end patch implements several related improvements to > tree-ssa's conditional (bit) constant propagation pass. The current > code handling ordered comparisons contains the comment "If the > most significant bits are not known we

[PATCH] Improve handling of unknown sign bit in CCP.

2021-08-08 Thread Roger Sayle
This middle-end patch implements several related improvements to tree-ssa's conditional (bit) constant propagation pass. The current code handling ordered comparisons contains the comment "If the most significant bits are not known we know nothing" which is not entirely true [this test even preve