Re: [rs6000 PATCH] Improve constant integer multiply using rldimi.

2022-06-27 Thread Segher Boessenkool
Hi! [Something is wrong with your mail program. It puts white lines everywhere, and prefixes a space to the existing white lines.] On Sun, Jun 26, 2022 at 09:56:07PM +0100, Roger Sayle wrote: > It turns out this optimization already exists in the form of a combine > splitter in rs6000.md, but th

Re: [rs6000 PATCH] Improve constant integer multiply using rldimi.

2022-06-27 Thread Kewen.Lin via Gcc-patches
Hi Roger, on 2022/6/27 04:56, Roger Sayle wrote: > > > This patch tweaks the code generated on POWER for integer multiplications > > by a constant, by making use of rldimi instructions. Much like x86's > > lea instruction, rldimi can be used to implement a shift and add pair > > in some cir

[rs6000 PATCH] Improve constant integer multiply using rldimi.

2022-06-26 Thread Roger Sayle
This patch tweaks the code generated on POWER for integer multiplications by a constant, by making use of rldimi instructions. Much like x86's lea instruction, rldimi can be used to implement a shift and add pair in some circumstances. For rldimi this is when the shifted operand is known t