Reapply "Remove configure checks for supported instruction sets"

I reverted this previously for 7.4 because of bug #78769. Relanding
it now for master, because I still believe that this change is
right, and if it causes complications, those indicate a bug elsewhere.

---

These were checking whether the instruction set is supported by
the host CPU, however they were only used to condition on whether
this instruction set is targeted at all. It would still use dynamic
dispatch (e.g. based on ifunc resolvers) to select the actual
implementation. Whether the target is guaranteed to support the
instruction set without dispatch is determined based on pre-defined
macros like __SSE2__.

This removes the configure-time builtin cpu checks to remove
confusion. Additionally this allows targeting an architecture that
is newer than the host architecture.

diff --git a/Zend/zend_portability.h b/Zend/zend_portability.h
index c561e0fdf2db0c806ed4f27746f4e0eb28a1f3aa..e1370eecf88f2aec0f8a5e9297144c946c2ddafe 100644 (file)
--- a/Zend/zend_portability.h
+++ b/Zend/zend_portability.h
@@ -494,21 +494,21 @@ extern "C++" {
 #endif
 
 #if (defined(__i386__) || defined(__x86_64__))
-# if PHP_HAVE_SSSE3_INSTRUCTIONS && defined(HAVE_TMMINTRIN_H)
-# define PHP_HAVE_SSSE3
+# if defined(HAVE_TMMINTRIN_H)
+#  define PHP_HAVE_SSSE3
 # endif
 
-# if PHP_HAVE_SSE4_2_INSTRUCTIONS && defined(HAVE_NMMINTRIN_H)
-# define PHP_HAVE_SSE4_2
+# if defined(HAVE_NMMINTRIN_H)
+#  define PHP_HAVE_SSE4_2
 # endif
 
 /*
  * AVX2 support was added in gcc 4.7, but AVX2 intrinsics don't work in
  * __attribute__((target("avx2"))) functions until gcc 4.9.
  */
-# if PHP_HAVE_AVX2_INSTRUCTIONS && defined(HAVE_IMMINTRIN_H) && \
+# if defined(HAVE_IMMINTRIN_H) && \
   (defined(__llvm__) || defined(__clang__) || (defined(__GNUC__) && ZEND_GCC_VERSION >= 4009))
-# define PHP_HAVE_AVX2
+#  define PHP_HAVE_AVX2
 # endif
 #endif
 

diff --git a/build/php.m4 b/build/php.m4
index 0ccd919344b164941a9d3b57f064cb26f85b8754..e3548e7cfa238a7c3dc19ac31263a40d9dabf3a8 100644 (file)
--- a/build/php.m4
+++ b/build/php.m4
@@ -2669,30 +2669,6 @@ AC_DEFUN([PHP_CHECK_BUILTIN_CPU_SUPPORTS], [
    [$have_builtin_cpu_supports], [Whether the compiler supports __builtin_cpu_supports])
 ])
 
-dnl
-dnl PHP_CHECK_CPU_SUPPORTS
-dnl
-AC_DEFUN([PHP_CHECK_CPU_SUPPORTS], [
-  AC_REQUIRE([PHP_CHECK_BUILTIN_CPU_INIT])
-  AC_REQUIRE([PHP_CHECK_BUILTIN_CPU_SUPPORTS])
-  have_ext_instructions=0
-  if test $have_builtin_cpu_supports = 1; then
-    AC_MSG_CHECKING([for $1 instructions supports])
-    AC_RUN_IFELSE([AC_LANG_SOURCE([[
-int main() {
-       return __builtin_cpu_supports("$1")? 0 : 1;
-}
-    ]])], [
-      have_ext_instructions=1
-      AC_MSG_RESULT([yes])
-    ], [
-      AC_MSG_RESULT([no])
-    ], [AC_MSG_RESULT([no])])
-  fi
-  AC_DEFINE_UNQUOTED(AS_TR_CPP([PHP_HAVE_$1_INSTRUCTIONS]),
-   [$have_ext_instructions], [Whether the compiler supports $1 instructions])
-])
-
 dnl
 dnl PHP_PATCH_CONFIG_HEADERS([FILE])
 dnl

diff --git a/configure.ac b/configure.ac
index 50cfd0d4190f74e4d19a7269f3f1634a25e64f7c..1a17aa904da4da979c1c3aaebaab48fb944fca22 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -499,12 +499,6 @@ PHP_CHECK_BUILTIN_CPU_INIT
 dnl Check __builtin_cpu_supports
 PHP_CHECK_BUILTIN_CPU_SUPPORTS
 
-dnl Check instructions.
-PHP_CHECK_CPU_SUPPORTS([ssse3])
-PHP_CHECK_CPU_SUPPORTS([sse4.2])
-PHP_CHECK_CPU_SUPPORTS([avx])
-PHP_CHECK_CPU_SUPPORTS([avx2])
-
 dnl Check for structure members.
 AC_CHECK_MEMBERS([struct tm.tm_gmtoff],,,[#include <time.h>])
 AC_CHECK_MEMBERS([struct stat.st_blksize, struct stat.st_rdev])