Remove Intel compiler support

include/linux/compiler-intel.h had no update in the past 3 years.

We often forget about the third C compiler to build the kernel.

For example, commit a0a12c3 ("asm goto: eradicate CC_HAS_ASM_GOTO")
only mentioned GCC and Clang.

init/Kconfig defines CC_IS_GCC and CC_IS_CLANG but not CC_IS_ICC,
and nobody has reported any issue.

I guess the Intel Compiler support is broken, and nobody is caring
about it.

Harald Arnesen pointed out ICC (classic Intel C/C++ compiler) is
deprecated:

    $ icc -v
    icc: remark #10441: The Intel(R) C++ Compiler Classic (ICC) is
    deprecated and will be removed from product release in the second half
    of 2023. The Intel(R) oneAPI DPC++/C++ Compiler (ICX) is the recommended
    compiler moving forward. Please transition to use this compiler. Use
    '-diag-disable=10441' to disable this message.
    icc version 2021.7.0 (gcc version 12.1.0 compatibility)

Arnd Bergmann provided a link to the article, "Intel C/C++ compilers
complete adoption of LLVM".

lib/zstd/common/compiler.h and lib/zstd/compress/zstd_fast.c were kept
untouched for better sync with https://github.com/facebook/zstd

Link: https://www.intel.com/content/www/us/en/developer/articles/technical/adoption-of-llvm-complete-icx.html
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/ia64/include/uapi/asm/cmpxchg.h

@@ -15,11 +15,7 @@
 #include <linux/types.h>
 /* include compiler specific intrinsics */
 #include <asm/ia64regs.h>
-#ifdef __INTEL_COMPILER
-# include <asm/intel_intrin.h>
-#else
-# include <asm/gcc_intrin.h>
-#endif
+#include <asm/gcc_intrin.h>
 
 /*
  * This function doesn't exist, so you'll get a linker error if

arch/ia64/include/uapi/asm/intrinsics.h

@@ -14,11 +14,7 @@
 #include <linux/types.h>
 /* include compiler specific intrinsics */
 #include <asm/ia64regs.h>
-#ifdef __INTEL_COMPILER
-# include <asm/intel_intrin.h>
-#else
-# include <asm/gcc_intrin.h>
-#endif
+#include <asm/gcc_intrin.h>
 #include <asm/cmpxchg.h>
 
 #define ia64_set_rr0_to_rr4(val0, val1, val2, val3, val4)		\

include/acpi/platform/acenv.h

@@ -148,15 +148,12 @@
  *
  *****************************************************************************/
 
-#if defined(__GNUC__) && !defined(__INTEL_COMPILER)
+#if defined(__GNUC__)
 #include <acpi/platform/acgcc.h>
 
 #elif defined(_MSC_VER)
 #include "acmsvc.h"
 
-#elif defined(__INTEL_COMPILER)
-#include <acpi/platform/acintel.h>
-
 #endif
 
 #if defined(_LINUX) || defined(__linux__)

include/acpi/platform/acenvex.h

@@ -35,7 +35,7 @@
 
 #endif
 
-#if defined(__GNUC__) && !defined(__INTEL_COMPILER)
+#if defined(__GNUC__)
 #include "acgccex.h"
 
 #elif defined(_MSC_VER)

include/linux/compiler_attributes.h

@@ -64,16 +64,10 @@
  * compiler should see some alignment anyway, when the return value is
  * massaged by 'flags = ptr & 3; ptr &= ~3;').
  *
- * Optional: not supported by icc
- *
  *   gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-assume_005faligned-function-attribute
  * clang: https://clang.llvm.org/docs/AttributeReference.html#assume-aligned
  */
-#if __has_attribute(__assume_aligned__)
-# define __assume_aligned(a, ...)       __attribute__((__assume_aligned__(a, ## __VA_ARGS__)))
-#else
-# define __assume_aligned(a, ...)
-#endif
+#define __assume_aligned(a, ...)        __attribute__((__assume_aligned__(a, ## __VA_ARGS__)))
 
 /*
  * Note the long name.
@@ -85,7 +79,6 @@
 /*
  * Optional: only supported since gcc >= 9
  * Optional: not supported by clang
- * Optional: not supported by icc
  *
  *   gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-copy-function-attribute
  */
@@ -98,7 +91,6 @@
 /*
  * Optional: not supported by gcc
  * Optional: only supported since clang >= 14.0
- * Optional: not supported by icc
  *
  * clang: https://clang.llvm.org/docs/AttributeReference.html#diagnose_as_builtin
  */
@@ -122,7 +114,6 @@
 
 /*
  * Optional: not supported by clang
- * Optional: not supported by icc
  *
  *   gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-designated_005finit-type-attribute
  */
@@ -236,7 +227,6 @@
 /*
  * Optional: only supported since gcc >= 8
  * Optional: not supported by clang
- * Optional: not supported by icc
  *
  *   gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-nonstring-variable-attribute
  */
@@ -267,7 +257,6 @@
 
 /*
  * Optional: not supported by gcc.
- * Optional: not supported by icc.
  *
  * clang: https://clang.llvm.org/docs/AttributeReference.html#overloadable
  */
@@ -287,7 +276,6 @@
  * Note: the "type" argument should match any __builtin_object_size(p, type) usage.
  *
  * Optional: not supported by gcc.
- * Optional: not supported by icc.
  *
  * clang: https://clang.llvm.org/docs/AttributeReference.html#pass-object-size-pass-dynamic-object-size
  */

include/linux/compiler_types.h

@@ -120,8 +120,6 @@ static inline void __chk_io_ptr(const volatile void __iomem *ptr) { }
 /* Compiler specific macros. */
 #ifdef __clang__
 #include <linux/compiler-clang.h>
-#elif defined(__INTEL_COMPILER)
-#include <linux/compiler-intel.h>
 #elif defined(__GNUC__)
 /* The above compilers also define __GNUC__, so order is important here. */
 #include <linux/compiler-gcc.h>

scripts/cc-version.sh

@@ -12,8 +12,6 @@ get_c_compiler_info()
 	cat <<- EOF | "$@" -E -P -x c - 2>/dev/null
 	#if defined(__clang__)
 	Clang	__clang_major__  __clang_minor__  __clang_patchlevel__
-	#elif defined(__INTEL_COMPILER)
-	ICC	__INTEL_COMPILER  __INTEL_COMPILER_UPDATE
 	#elif defined(__GNUC__)
 	GCC	__GNUC__  __GNUC_MINOR__  __GNUC_PATCHLEVEL__
 	#else