Hi,
this patch adds more tunes for zen4:
- new tunes for avx512 scater instructions.
In micro benchmarks these seems consistent loss compared to open-coded coe
- disable use of gather for zen4
While these are win for a micro benchmarks (based on TSVC), enabling gather
is a loss for parest. So for now it seems safe to keep it off.
- disable pass to avoid FMA chains for znver4 since fmadd was optimized and
does not seem
to cause regressions.
Bootstrapped/regtested x86_64.
Honza
* i386.cc (ix86_vectorize_builtin_scatter): Guard scatter by
TARGET_USE_SCATTER.
* i386.h (TARGET_USE_SCATTER_2PARTS, TARGET_USE_SCATTER_4PARTS,
TARGET_USE_SCATTER): New macros.
* x86-tune.def (TARGET_USE_SCATTER_2PARTS, TARGET_USE_SCATTER_4PARTS,
TARGET_USE_SCATTER): New tunes.
(X86_TUNE_AVOID_256FMA_CHAINS, X86_TUNE_AVOID_512FMA_CHAINS): Disable
for znver4.
(X86_TUNE_USE_GATHER): Disable for zen4.
diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
index de978d19063..9fb69f6c174 100644
--- a/gcc/config/i386/i386.cc
+++ b/gcc/config/i386/i386.cc
@@ -19051,6 +19051,13 @@ ix86_vectorize_builtin_scatter (const_tree vectype,
if (!TARGET_AVX512F)
return NULL_TREE;
+ if (known_eq (TYPE_VECTOR_SUBPARTS (vectype), 2u)
+ ? !TARGET_USE_SCATTER_2PARTS
+ : (known_eq (TYPE_VECTOR_SUBPARTS (vectype), 4u)
+ ? !TARGET_USE_SCATTER_4PARTS
+ : !TARGET_USE_SCATTER))
+ return NULL_TREE;
+
if ((TREE_CODE (index_type) != INTEGER_TYPE
&& !POINTER_TYPE_P (index_type))
|| (TYPE_MODE (index_type) != SImode
diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h
index e6a603ed31a..cd7ed19e29c 100644
--- a/gcc/config/i386/i386.h
+++ b/gcc/config/i386/i386.h
@@ -397,10 +397,16 @@ extern unsigned char ix86_tune_features[X86_TUNE_LAST];
ix86_tune_features[X86_TUNE_AVOID_4BYTE_PREFIXES]
#define TARGET_USE_GATHER_2PARTS \
ix86_tune_features[X86_TUNE_USE_GATHER_2PARTS]
+#define TARGET_USE_SCATTER_2PARTS \
+ ix86_tune_features[X86_TUNE_USE_SCATTER_2PARTS]
#define TARGET_USE_GATHER_4PARTS \
ix86_tune_features[X86_TUNE_USE_GATHER_4PARTS]
+#define TARGET_USE_SCATTER_4PARTS \
+ ix86_tune_features[X86_TUNE_USE_SCATTER_4PARTS]
#define TARGET_USE_GATHER \
ix86_tune_features[X86_TUNE_USE_GATHER]
+#define TARGET_USE_SCATTER \
+ ix86_tune_features[X86_TUNE_USE_SCATTER]
#define TARGET_FUSE_CMP_AND_BRANCH_32 \
ix86_tune_features[X86_TUNE_FUSE_CMP_AND_BRANCH_32]
#define TARGET_FUSE_CMP_AND_BRANCH_64 \
diff --git a/gcc/config/i386/x86-tune.def b/gcc/config/i386/x86-tune.def
index fae3b650434..7e9c7244fc0 100644
--- a/gcc/config/i386/x86-tune.def
+++ b/gcc/config/i386/x86-tune.def
@@ -483,28 +483,43 @@ DEF_TUNE (X86_TUNE_AVOID_4BYTE_PREFIXES,
"avoid_4byte_prefixes",
DEF_TUNE (X86_TUNE_USE_GATHER_2PARTS, "use_gather_2parts",
~(m_ZNVER1 | m_ZNVER2 | m_ZNVER3 | m_ZNVER4 | m_ALDERLAKE |
m_CORE_ATOM | m_GENERIC))
+/* X86_TUNE_USE_SCATTER_2PARTS: Use scater instructions for vectors with 2
+ elements. */
+DEF_TUNE (X86_TUNE_USE_SCATTER_2PARTS, "use_scatter_2parts",
+ ~(m_ZNVER4 | m_GENERIC))
+
/* X86_TUNE_USE_GATHER_4PARTS: Use gather instructions for vectors with 4
elements. */
DEF_TUNE (X86_TUNE_USE_GATHER_4PARTS, "use_gather_4parts",
~(m_ZNVER1 | m_ZNVER2 | m_ZNVER3 | m_ZNVER4 | m_ALDERLAKE |
m_CORE_ATOM | m_GENERIC))
+/* X86_TUNE_USE_SCATTER_4PARTS: Use scater instructions for vectors with 4
+ elements. */
+DEF_TUNE (X86_TUNE_USE_SCATTER_4PARTS, "use_scatter_4parts",
+ ~(m_ZNVER4 | m_GENERIC))
+
/* X86_TUNE_USE_GATHER: Use gather instructions for vectors with 8 or more
elements. */
DEF_TUNE (X86_TUNE_USE_GATHER, "use_gather",
- ~(m_ZNVER1 | m_ZNVER2 | m_ALDERLAKE | m_CORE_ATOM | m_GENERIC))
+ ~(m_ZNVER1 | m_ZNVER2 | m_ZNVER4 | m_ALDERLAKE | m_CORE_ATOM |
m_GENERIC))
+
+/* X86_TUNE_USE_SCATTER: Use scater instructions for vectors with 8 or more
+ elements. */
+DEF_TUNE (X86_TUNE_USE_SCATTER, "use_scatter",
+ ~(m_ZNVER4 | m_GENERIC))
/* X86_TUNE_AVOID_128FMA_CHAINS: Avoid creating loops with tight 128bit or
smaller FMA chain. */
-DEF_TUNE (X86_TUNE_AVOID_128FMA_CHAINS, "avoid_fma_chains", m_ZNVER)
+DEF_TUNE (X86_TUNE_AVOID_128FMA_CHAINS, "avoid_fma_chains", m_ZNVER1 |
m_ZNVER2 | m_ZNVER3)
/* X86_TUNE_AVOID_256FMA_CHAINS: Avoid creating loops with tight 256bit or
smaller FMA chain. */
-DEF_TUNE (X86_TUNE_AVOID_256FMA_CHAINS, "avoid_fma256_chains", m_ZNVER2 |
m_ZNVER3 | m_ZNVER4
+DEF_TUNE (X86_TUNE_AVOID_256FMA_CHAINS, "avoid_fma256_chains", m_ZNVER2 |
m_ZNVER3
| m_ALDERLAKE | m_SAPPHIRERAPIDS | m_CORE_ATOM)
/* X86_TUNE_AVOID_512FMA_CHAINS: Avoid creating loops with tight 512bit or
smaller FMA chain. */
-DEF_TUNE (X86_TUNE_AVOID_512FMA_CHAINS, "avoid_fma512_chains", m_ZNVER4)
+DEF_TUNE (X86_TUNE_AVOID_512FMA_CHAINS, "avoid_fma512_chains", m_NONE)
/* X86_TUNE_V2DF_REDUCTION_PREFER_PHADDPD: Prefer haddpd
for v2df vector reduction. */
