https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110434
Bug ID: 110434
Summary: tree-nrv introduces incorrect CLOBBER(eol)
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: kristerw at gcc dot gnu.org
Target Milestone: ---
The tree-nrv pass may introduce incorrect CLOBBER(eol) of the form
<retval> ={v} {CLOBBER(eol)};
return <retval>;
One example of this can be seen by compiling gcc.c-torture/execute/921204-1.c
for x86 using the flags "-O -m32", where it changes the IR
union bu o;
...
o = i;
MEM[(union *)&o].b18 = _11;
MEM[(union *)&o].b20 = _11;
<retval> = o;
o ={v} {CLOBBER(eol)};
return <retval>;
to just use <retval> instead of o
union bu o [value-expr: <retval>];
...
<retval> = i;
MEM[(union *)&<retval>].b18 = _11;
MEM[(union *)&<retval>].b20 = _11;
<retval> ={v} {CLOBBER(eol)};
return <retval>;
so the CLOBBER(eol) now refers to <retval>.
