[Bug middle-end/32686] New: Code to convert double to _Complex double for arguments passing is not good (extra load)

[Bug middle-end/32686] New: Code to convert double to _Complex double for arguments passing is not good (extra load)

[pinskia at gcc dot gnu dot org]

Testcase:
_Complex double f(_Complex double);
_Complex double g(double a)
{
  return f(a);
}

----- Cut ----
We currently get:
        mflr r0
        bcl 20,31,"L00000000001$pb"
"L00000000001$pb":
        stw r31,-4(r1)
        mflr r31
        stfd f1,-24(r1)
        mtlr r0
        lwz r3,-24(r1)
        lwz r4,-20(r1)
        addis r2,r31,ha16(LC0-"L00000000001$pb")
        lwz r31,-4(r1)
        la r5,lo16(LC0-"L00000000001$pb")(r2)
        lwz r6,4(r5)
        lwz r5,0(r5)
        b L_f$stub

We should be able to get:
        stfd f1,-8(r1)
        li r6,0
        li r5,0
        lwz r3,-8(r1)
        lwz r4,-4(r1)
        b L_f$stub

Without the need for the PIC register.


-- 
           Summary: Code to convert double to _Complex double for arguments
                    passing is not good (extra load)
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org
GCC target triplet: powerpc-darwin


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32686

[Bug middle-end/32686] Code to convert double to _Complex double for arguments passing is not good (extra load)

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2007-07-09 03:33 -------
powerpc64-darwin is just as bad, we get:
        mflr r0
        std r31,-8(r1)
        stfd f1,-32(r1)
        bcl 20,31,"L00000000001$pb"
"L00000000001$pb":
        mflr r31
        addis r2,r31,ha16(LC0-"L00000000001$pb")
        mtlr r0
        ld r4,lo16(LC0-"L00000000001$pb")(r2)
        ld r3,-32(r1)
        ld r31,-8(r1)
        b L_f$stub

When we should get:

        stfd f1,-8(r1)
        li r4,0
        ld r3,-8(r1)
        b L_f$stub

With a few nops through in there so we don't reject the distpatch group.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32686