Re: [PATCH] PR rtl-optimization/109476: Use ZERO_EXTEND instead of zeroing a SUBREG.

2023-04-28 Thread Richard Biener via Gcc-patches
On Sun, Apr 23, 2023 at 10:14 PM Roger Sayle wrote: > > > This patch fixes PR rtl-optimization/109476, which is a code quality > regression affecting AVR. The cause is that the lower-subreg pass is > sometimes overly aggressive, lowering the LSHIFTRT below: > > (insn 7 4 8 2 (set (reg:HI 51) >

[PATCH] PR rtl-optimization/109476: Use ZERO_EXTEND instead of zeroing a SUBREG.

2023-04-23 Thread Roger Sayle
This patch fixes PR rtl-optimization/109476, which is a code quality regression affecting AVR. The cause is that the lower-subreg pass is sometimes overly aggressive, lowering the LSHIFTRT below: (insn 7 4 8 2 (set (reg:HI 51) (lshiftrt:HI (reg/v:HI 49 [ b ]) (const_int 8 [0x