https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106592
Bug ID: 106592
Summary: s390: Inefficient branchless conditionals for long
long
Product: gcc
Version: 11.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: jens.seifert at de dot ibm.com
Target Milestone: ---
Created attachment 53443
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53443&action=edit
source code
long long gtRef(long long a, long long b)
{
return a > b;
}
Generates:
cgr %r2,%r3
lghi %r1,0
lghi %r2,1
locgrnh %r2,%r1
Better sequence:
cgr %r2,%r3
lghi %r2,0
alcgr %r2,%r2
long long leMaskRef(long long a, long long b)
{
return -(a <= b);
}
Generates:
cgr %r2,%r3
lhi %r1,0
lhi %r2,1
locrnle %r2,%r1
sllg %r2,%r2,63
srag %r2,%r2,63
Better sequence:
cgr %r2,%r3
slbgr %r2,%r2
long long gtMaskRef(long long a, long long b)
{
return -(a > b);
}
Generates:
cgr %r2,%r3
lhi %r1,0
lhi %r2,1
locrnh %r2,%r1
sllg %r2,%r2,63
srag %r2,%r2,63
Better sequence:
cgr %r2,%r3
lghi %r2,0
alcgr %r2,%r2
lcgr %r2,%r2
