https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108009
Bug ID: 108009
Summary: GCC does not produce Pack Halfword instructions
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: chris.sidebottom at arm dot com
Target Milestone: ---
I've been trying to remove a dependency on CMSIS intrinsics
(https://github.com/ARM-software/CMSIS_5/blob/develop/CMSIS/Core/Include/cmsis_gcc.h),
following https://arm-software.github.io/acle/main/acle.html, I should be able
to generate a halfword packing instructions
(https://developer.arm.com/documentation/dui0489/h/arm-and-thumb-instructions/pkhbt-and-pkhtb)
using C, such as:
int pack(int x, int y) {
return ((x & 0xFFFFu) << 16) | (y & 0xffffu);
}
However, `gcc -mcpu=cortex-m4 -O3` results in two instructions rather than the
single halfword packing instruction.
