https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103797
Bug ID: 103797
Summary: Clang vectorized LightPixel while GCC does not
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: hubicka at gcc dot gnu.org
Target Milestone: ---
Clang vectorises divss in LightPixel while GCC does not (at -O3). This seems
to account for 17% difference in resteflood_svg benchmark of Firefox.
│ 0000000001864660 <mozilla::gfx::(anonymous
namespace)::SpecularLightingSoftware::LightPixel(mozilla::gfx::Point3DTyped<mozilla::gfx::UnknownUnits,
float> const&, mozilla::gfx::Point3DTyped<mozilla::gfx::UnknownUnits, float>
const&, unsigned int)>:
│ mozilla::gfx::(anonymous
namespace)::SpecularLightingSoftware::LightPixel(mozilla::gfx::Point3DTyped<mozilla::gfx::UnknownUnits,
float> const&, mozilla::gfx::Point3DTyped<mozilla::gfx::UnknownUnits, float>
const&, unsigned int):
0.05 │ push %rbp
0.07 │ mov %rsp,%rbp
0.71 │ xorps %xmm6,%xmm6
0.32 │ addss %xmm6,%xmm4
│ unpcklps %xmm3,%xmm5
0.78 │ movss
anon.5bcbce9b5eeaaf1a18a99b9a5b62e1ce.3.llvm.5306652999446557335+0x6d8,%xmm8
0.01 │ addps %xmm8,%xmm5
1.47 │ movaps %xmm4,%xmm9
│ mulss %xmm4,%xmm9
│ movaps %xmm5,%xmm7
0.01 │ mulps %xmm5,%xmm7
3.35 │ movaps %xmm7,%xmm3
│ shufps $0x55,%xmm7,%xmm3
0.99 │ addss %xmm9,%xmm3
1.59 │ addss %xmm7,%xmm3
2.01 │ sqrtss %xmm3,%xmm3
11.43 │ divss %xmm3,%xmm4
6.76 │ shufps $0x0,%xmm3,%xmm3
0.01 │ divps %xmm3,%xmm5
2.58 │ mulss %xmm1,%xmm4
0.04 │ unpcklps %xmm0,%xmm2
│ mulps %xmm5,%xmm2
2.67 │ movaps %xmm2,%xmm0
0.04 │ shufps $0x55,%xmm2,%xmm0
2.11 │ addss %xmm4,%xmm0
1.87 │ addss %xmm2,%xmm0
2.82 │ cmpless %xmm0,%xmm6
2.20 │ andps %xmm8,%xmm6
1.05 │ mulss %xmm0,%xmm6
4.04 │ mulss .str.6.llvm.231702015065810902+0x77,%xmm6
3.14 │ cvttss2si %xmm6,%eax
4.45 │ mov 0x8(%rdi),%ecx
0.00 │ mov 0xc(%rdi),%edx
│ movzwl %ax,%eax
1.10 │ test %edx,%edx
│ ↓ jle 92
│88: imul %eax,%eax
9.06 │ shr $0xf,%eax
3.12 │ dec %edx
│ ↑ jne 88
│92: shr $0x8,%eax
1.95 │ movzwl 0x10(%rdi,%rax,2),%eax
6.48 │ imul %eax,%ecx
0.99 │ shr $0x8,%ecx
1.06 │ mov %esi,%eax
0.01 │ shr $0x8,%eax
│ mov %esi,%edx
│ shr $0x10,%edx
0.01 │ mov $0xff,%edi
│ and %edi,%esi
0.01 │ imul %ecx,%esi
3.32 │ shr $0xf,%esi
1.81 │ cmp %edi,%esi ▒
0.04 │ cmovae %edi,%esi ▒
1.99 │ and %edi,%eax ▒
0.01 │ imul %ecx,%eax ▒
│ shr $0xf,%eax ▒
0.01 │ cmp %edi,%eax ▒
0.28 │ cmovae %edi,%eax ▒
0.96 │ and %edi,%edx ▒
│ imul %ecx,%edx ▒
│ shr $0xf,%edx ▒
0.92 │ cmp %edi,%edx ▒
0.85 │ cmovae %edi,%edx ▒
1.00 │ cmp %eax,%edx ▒
1.20 │ mov %eax,%ecx ▒
│ cmova %edx,%ecx ▒
2.17 │ cmp %esi,%ecx ▒
1.15 │ cmovbe %esi,%ecx ▒
1.79 │ shl $0x18,%ecx▒
1.17 │ shl $0x10,%edx▒
│ shl $0x8,%eax ▒
0.03 │ or %edx,%eax ▒
0.01 │ or %esi,%eax ▒
0.14 │ or %ecx,%eax ▒
0.72 │ pop %rbp ▒
0.04 │ ← ret
▒
