Re: [PATCH] PR rtl-optimization/46235: Improved use of bt for bit tests on x86_64.

2021-06-15 Thread Uros Bizjak via Gcc-patches
On Tue, Jun 15, 2021 at 5:17 PM Roger Sayle wrote: > > > This patch tackles PR46235 to improve the code generated for bit tests > on x86_64 by making more use of the bt instruction. Currently, GCC emits > bt instructions when followed by condition jumps (thanks to Uros' > splitters). > This patch

[PATCH] PR rtl-optimization/46235: Improved use of bt for bit tests on x86_64.

2021-06-15 Thread Roger Sayle
This patch tackles PR46235 to improve the code generated for bit tests on x86_64 by making more use of the bt instruction. Currently, GCC emits bt instructions when followed by condition jumps (thanks to Uros' splitters). This patch adds splitters in i386.md, to catch the cases where bt is follow