i386: Rename TARGET_USE_XCHG_FOR_ATOMIC_STORE to TARGET_AVOID_MFENCE.

2020-07-21  Uroš Bizjak  <ubizjak@gmail.com>

gcc/ChangeLog:

	* config/i386/i386.h (TARGET_AVOID_MFENCE):
	Rename from TARGET_USE_XCHG_FOR_ATOMIC_STORE.
	* config/i386/sync.md (atomic_store<mode>): Update for rename.
	* config/i386/x86-tune.def (X86_TUNE_AVOID_MFENCE):
	Rename from X86_TUNE_USE_XCHG_FOR_ATOMIC_STORE.

diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h
index 23a513d8ffd51094e6b9c2cb0beed3f8d60b7481..4ff8b5e6562c3000a2221900cd7f3473a9ac31f2 100644 (file)
--- a/gcc/config/i386/i386.h
+++ b/gcc/config/i386/i386.h
@@ -592,8 +592,7 @@ extern unsigned char ix86_tune_features[X86_TUNE_LAST];
        ix86_tune_features[X86_TUNE_AVOID_FALSE_DEP_FOR_BMI]
 #define TARGET_ONE_IF_CONV_INSN \
        ix86_tune_features[X86_TUNE_ONE_IF_CONV_INSN]
-#define TARGET_USE_XCHG_FOR_ATOMIC_STORE \
-       ix86_tune_features[X86_TUNE_USE_XCHG_FOR_ATOMIC_STORE]
+#define TARGET_AVOID_MFENCE ix86_tune_features[X86_TUNE_AVOID_MFENCE]
 #define TARGET_EMIT_VZEROUPPER \
        ix86_tune_features[X86_TUNE_EMIT_VZEROUPPER]
 #define TARGET_EXPAND_ABS \

diff --git a/gcc/config/i386/sync.md b/gcc/config/i386/sync.md
index 9ab5456b2274ca540e135ff67f570aa4f1cce39e..502d56737897bb44cfd0bca249ae3f4fcfd3cb0f 100644 (file)
--- a/gcc/config/i386/sync.md
+++ b/gcc/config/i386/sync.md
@@ -306,11 +306,10 @@
     {
       operands[1] = force_reg (<MODE>mode, operands[1]);
 
-      /* For seq-cst stores, use XCHG when we lack MFENCE
-        or when target prefers XCHG.  */
+      /* For seq-cst stores, use XCHG when we lack MFENCE.  */
       if (is_mm_seq_cst (model)
          && (!(TARGET_64BIT || TARGET_SSE2)
-             || TARGET_USE_XCHG_FOR_ATOMIC_STORE))
+             || TARGET_AVOID_MFENCE))
        {
          emit_insn (gen_atomic_exchange<mode> (gen_reg_rtx (<MODE>mode),
                                                operands[0], operands[1],

diff --git a/gcc/config/i386/x86-tune.def b/gcc/config/i386/x86-tune.def
index 1776aba2d1715dc119c2f2c035baf22ef77ebfaa..6eff825689704cb2120d5b5ab320a118012d6096 100644 (file)
--- a/gcc/config/i386/x86-tune.def
+++ b/gcc/config/i386/x86-tune.def
@@ -313,8 +313,8 @@ DEF_TUNE (X86_TUNE_ONE_IF_CONV_INSN, "one_if_conv_insn",
          m_SILVERMONT | m_KNL | m_KNM | m_INTEL | m_CORE_ALL | m_GOLDMONT
          | m_GOLDMONT_PLUS | m_TREMONT | m_GENERIC)
 
-/* X86_TUNE_USE_XCHG_FOR_ATOMIC_STORE: Use xchg instead of mov+mfence.  */
-DEF_TUNE (X86_TUNE_USE_XCHG_FOR_ATOMIC_STORE, "use_xchg_for_atomic_store",
+/* X86_TUNE_AVOID_MFENCE: Use lock prefixed instructions instead of mfence.  */
+DEF_TUNE (X86_TUNE_AVOID_MFENCE, "avoid_mfence",
         m_CORE_ALL | m_BDVER | m_ZNVER | m_GENERIC)
 
 /* X86_TUNE_EXPAND_ABS: This enables a new abs pattern by