https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123148
Bug ID: 123148
Summary: Would be nice to output non-zero bits to debug dump
during combine
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Keywords: internal-improvement
Severity: enhancement
Priority: P3
Component: rtl-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Target Milestone: ---
With the testcase for PR 123133 (on aarch64).
The dump shows:
```
Trying 11 -> 13:
11: r111:SI=r112:SI-r107:SI
REG_DEAD r112:SI
REG_DEAD r107:SI
REG_EQUAL 0x7-r107:SI
13: r105:DI=sign_extend(r111:SI)
REG_DEAD r111:SI
Failed to match this instruction:
(set (reg:DI 105 [ _4 ])
(sign_extend:DI (minus:SI (reg:SI 112)
(reg:SI 107 [ _1 ]))))
```
It would be nice to output the known non-zero bits of r112 and r107 (and r111).
so it might be easy to see could be changed to a zero_extend or we are missing
some tracking somewhere.
