On 10/14/21 7:42 PM, H.J. Lu wrote:
On Thu, Oct 14, 2021 at 11:06 AM Andrew MacLeod via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
As the PR observes, if the first operand of a right shift is 0 or -1,
operand 2 doesn't matter and the result will be the same as op1, so it
can be turned into a copy.
This patch checks for that condition and performs the operation in EVRP.
Bootstrapped on x86_64-pc-linux-gnu with no regressions. Pushed.
Andrew
/* PR tree-optimization/102738 */
+/* { dg-options "-O2 -fdump-tree-evrp" } */
+
+/* Remove arithmetic shift right when the LHS is known to be 0 or -1. */
+
+int a1(__int128 f, int g)
Missing
/* { dg-do compile { target int128 } } */
Thanks.. Done. Feel free to bypass me :-)
Andrew
