r254152 disabled partial_reg_dependency and movx for Haswell and newer
Intel processors. r258972 restored them for skylake-avx512. For Haswell,
movx improves performance. But partial_reg_stall may be better than
partial_reg_dependency in theory. We will investigate performance impact
of partial_reg_stall vs partial_reg_dependency on Haswell for GCC 9. In
the meantime, this patch restores both partial_reg_dependency and mox for
Haswell in GCC 8.
OK for GCC 8?
H.J.
---
PR target/85829
* config/i386/x86-tune.def: Re-enable partial_reg_dependency
and movx for Haswell.
---
gcc/config/i386/x86-tune.def | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/gcc/config/i386/x86-tune.def b/gcc/config/i386/x86-tune.def
index 5649fdcf416..60625668236 100644
--- a/gcc/config/i386/x86-tune.def
+++ b/gcc/config/i386/x86-tune.def
@@ -48,7 +48,7 @@ DEF_TUNE (X86_TUNE_SCHEDULE, "schedule",
over partial stores. For example preffer MOVZBL or MOVQ to load 8bit
value over movb. */
DEF_TUNE (X86_TUNE_PARTIAL_REG_DEPENDENCY, "partial_reg_dependency",
- m_P4_NOCONA | m_CORE2 | m_NEHALEM | m_SANDYBRIDGE
+ m_P4_NOCONA | m_CORE2 | m_NEHALEM | m_SANDYBRIDGE | m_HASWELL
| m_BONNELL | m_SILVERMONT | m_INTEL
| m_KNL | m_KNM | m_AMD_MULTIPLE | m_SKYLAKE_AVX512 | m_GENERIC)
@@ -84,7 +84,7 @@ DEF_TUNE (X86_TUNE_PARTIAL_FLAG_REG_STALL,
"partial_flag_reg_stall",
partial dependencies. */
DEF_TUNE (X86_TUNE_MOVX, "movx",
m_PPRO | m_P4_NOCONA | m_CORE2 | m_NEHALEM | m_SANDYBRIDGE
- | m_BONNELL | m_SILVERMONT | m_KNL | m_KNM | m_INTEL
+ | m_BONNELL | m_SILVERMONT | m_KNL | m_KNM | m_INTEL | m_HASWELL
| m_GEODE | m_AMD_MULTIPLE | m_SKYLAKE_AVX512 | m_GENERIC)
/* X86_TUNE_MEMORY_MISMATCH_STALL: Avoid partial stores that are followed by
--
2.17.0
