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From: "pc at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug target/103605] New: [PowerPC] fmin/fmax should be inlined
 always with xsmindp/xsmaxdp
Date: Tue, 07 Dec 2021 16:21:05 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D103605

            Bug ID: 103605
           Summary: [PowerPC] fmin/fmax should be inlined always with
                    xsmindp/xsmaxdp
           Product: gcc
           Version: 11.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pc at gcc dot gnu.org
  Target Milestone: ---

--
$ gcc --version
gcc (GCC) 11.2.1 20210728 (Red Hat 11.2.1-2)
[...]
$ gcc -c -O2 fmin.c && objdump -dr fmin.o
   0:   00 00 4c 3c     addis   r2,r12,0
                        0: R_PPC64_REL16_HA     .TOC.
   4:   00 00 42 38     addi    r2,r2,0
                        4: R_PPC64_REL16_LO     .TOC.+0x4
   8:   a6 02 08 7c     mflr    r0
   c:   10 00 01 f8     std     r0,16(r1)
  10:   e1 ff 21 f8     stdu    r1,-32(r1)
  14:   01 00 00 48     bl      14 <fm+0x14>
                        14: R_PPC64_REL24       fmin
  18:   00 00 00 60     nop
  1c:   20 00 21 38     addi    r1,r1,32
  20:   10 00 01 e8     ld      r0,16(r1)
  24:   a6 03 08 7c     mtlr    r0
  28:   20 00 80 4e     blr
$ gcc -c -O2 fmin.c -ffast-math && objdump -dr fmin.o
   0:   40 14 21 f0     xsmincdp vs1,vs1,vs2
   4:   20 00 80 4e     blr
--

And it appears that a better instruction choice in the above case is xsmind=
p,
and it can be used with and without "-ffast-math", as it matches the semant=
ics
required of fmin.  Similarly, xsmaxdp with fmax.=