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Re: [PATCH i386] Introduce __readeflags () and __writeeflags () intrinsics.
- From: Kirill Yukhin <kirill dot yukhin at gmail dot com>
- To: Uros Bizjak <ubizjak at gmail dot com>
- Cc: Jakub Jelinek <jakub at redhat dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 5 Dec 2013 13:20:06 +0300
- Subject: Re: [PATCH i386] Introduce __readeflags () and __writeeflags () intrinsics.
- Authentication-results: sourceware.org; auth=none
- References: <20131204165948 dot GA21551 at msticlxl57 dot ims dot intel dot com> <CAFULd4aP7v=DvAaE8dmeZ5dTeZbZiW0Bf2P+XqfuAKo=+q9bnw at mail dot gmail dot com> <20131205074620 dot GA10863 at msticlxl57 dot ims dot intel dot com> <CAFULd4b+ovopW+nfQcJhV32o78kjoLYyyymyT_stZWsOc+Y_qg at mail dot gmail dot com>
On 05 Dec 09:01, Uros Bizjak wrote:
> On Thu, Dec 5, 2013 at 8:46 AM, Kirill Yukhin <kirill.yukhin@gmail.com> wrote:
> > + emit_insn (gen_push (gen_rtx_REG (CCmode, FLAGS_REG)));
>
> The FLAGS_REG shuold be generated in an integer mode, appropriate for the push!
I suppose, `word_mode' is correct mode throughout these built-ins expanding.
> > + emit_insn (gen_pop (target));
> > + return target;
>
> Please note that "target" can be null, so you need to generate a
> register and move insn in this case. Please see many examples in
> i386.c expander code.
Fixed.
> > + case IX86_BUILTIN_WRITE_FLAGS:
> > + arg0 = CALL_EXPR_ARG (exp, 0);
> > + emit_insn (gen_push (expand_normal (arg0)));
>
> This expand normal is too simple, you need to check predicate and move
> argument to a mode register. Also, there are many examples througout
> i386.c expanders.
Fixed using `push_operand' predicate.
> > + emit_insn (gen_pop (gen_rtx_REG (CCmode, FLAGS_REG)));
>
> Again, FLAGS_REG should be generated in a correct mode. I wonder if
> "flags_reg_operand" correctly checks operand mode ...
Fixed.
> > +(define_insn "*popfl<mode>1"
>
> You can remove trailing 1 here ...
Fixed.
Bootstrapped. Tests still pass.
Changelogs untouched.
Is it ok?
--
Thanks, K
gcc/config/i386/i386.c | 37 +++++++++++++++++++++++++
gcc/config/i386/i386.md | 17 ++++++++++++
gcc/config/i386/ia32intrin.h | 33 ++++++++++++++++++++++
gcc/testsuite/gcc.target/i386/readeflags-1.c | 40 +++++++++++++++++++++++++++
gcc/testsuite/gcc.target/i386/writeeflags-1.c | 30 ++++++++++++++++++++
5 files changed, 157 insertions(+)
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 21963bb..5bf358e 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -27909,6 +27909,10 @@ enum ix86_builtins
IX86_BUILTIN_CPU_IS,
IX86_BUILTIN_CPU_SUPPORTS,
+ /* Read/write FLAGS register built-ins. */
+ IX86_BUILTIN_READ_FLAGS,
+ IX86_BUILTIN_WRITE_FLAGS,
+
IX86_BUILTIN_MAX
};
@@ -29750,6 +29754,17 @@ ix86_init_mmx_sse_builtins (void)
UCHAR_FTYPE_UCHAR_ULONGLONG_ULONGLONG_PULONGLONG,
IX86_BUILTIN_ADDCARRYX64);
+ /* Read/write FLAGS. */
+ def_builtin (~OPTION_MASK_ISA_64BIT, "__builtin_ia32_readeflags_u32",
+ UNSIGNED_FTYPE_VOID, IX86_BUILTIN_READ_FLAGS);
+ def_builtin (OPTION_MASK_ISA_64BIT, "__builtin_ia32_readeflags_u64",
+ UINT64_FTYPE_VOID, IX86_BUILTIN_READ_FLAGS);
+ def_builtin (~OPTION_MASK_ISA_64BIT, "__builtin_ia32_writeeflags_u32",
+ VOID_FTYPE_UNSIGNED, IX86_BUILTIN_WRITE_FLAGS);
+ def_builtin (OPTION_MASK_ISA_64BIT, "__builtin_ia32_writeeflags_u64",
+ VOID_FTYPE_UINT64, IX86_BUILTIN_WRITE_FLAGS);
+
+
/* Add FMA4 multi-arg argument instructions */
for (i = 0, d = bdesc_multi_arg; i < ARRAY_SIZE (bdesc_multi_arg); i++, d++)
{
@@ -33378,6 +33393,28 @@ addcarryx:
emit_insn (gen_rtx_SET (VOIDmode, target, pat));
return target;
+ case IX86_BUILTIN_READ_FLAGS:
+ emit_insn (gen_push (gen_rtx_REG (word_mode, FLAGS_REG)));
+
+ if (target == NULL_RTX
+ || !register_operand (target, word_mode)
+ || GET_MODE (target) != word_mode)
+ target = gen_reg_rtx (word_mode);
+
+ emit_insn (gen_pop (target));
+ return target;
+
+ case IX86_BUILTIN_WRITE_FLAGS:
+
+ arg0 = CALL_EXPR_ARG (exp, 0);
+ op0 = expand_normal (arg0);
+ if (!push_operand (op0, word_mode))
+ op0 = copy_to_mode_reg (word_mode, op0);
+
+ emit_insn (gen_push (op0));
+ emit_insn (gen_pop (gen_rtx_REG (word_mode, FLAGS_REG)));
+ return 0;
+
case IX86_BUILTIN_GATHERSIV2DF:
icode = CODE_FOR_avx2_gathersiv2df;
goto gather_gen;
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 6976124..272fbdf 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -1714,6 +1714,23 @@
"pop{<imodesuffix>}\t%0"
[(set_attr "type" "pop")
(set_attr "mode" "<MODE>")])
+
+(define_insn "*pushfl<mode>"
+ [(set (match_operand:DWIH 0 "push_operand" "=<")
+ (match_operand:DWIH 1 "flags_reg_operand"))]
+ ""
+ "pushf{<imodesuffix>}"
+ [(set_attr "type" "push")
+ (set_attr "mode" "<MODE>")])
+
+(define_insn "*popfl<mode>"
+ [(set (match_operand:DWIH 0 "flags_reg_operand")
+ (match_operand:DWIH 1 "pop_operand" ">"))]
+ ""
+ "popf{<imodesuffix>}"
+ [(set_attr "type" "pop")
+ (set_attr "mode" "<MODE>")])
+
;; Move instructions.
diff --git a/gcc/config/i386/ia32intrin.h b/gcc/config/i386/ia32intrin.h
index b26dc46..65642e4 100644
--- a/gcc/config/i386/ia32intrin.h
+++ b/gcc/config/i386/ia32intrin.h
@@ -238,6 +238,22 @@ __rorq (unsigned long long __X, int __C)
return (__X >> __C) | (__X << (64 - __C));
}
+/* Read flags register */
+extern __inline unsigned long long
+__attribute__((__gnu_inline__, __always_inline__, __artificial__))
+__readeflags (void)
+{
+ return __builtin_ia32_readeflags_u64 ();
+}
+
+/* Write flags register */
+extern __inline void
+__attribute__((__gnu_inline__, __always_inline__, __artificial__))
+__writeeflags (unsigned long long X)
+{
+ __builtin_ia32_writeeflags_u64 (X);
+}
+
#define _bswap64(a) __bswapq(a)
#define _popcnt64(a) __popcntq(a)
#define _lrotl(a,b) __rolq((a), (b))
@@ -245,6 +261,23 @@ __rorq (unsigned long long __X, int __C)
#else
#define _lrotl(a,b) __rold((a), (b))
#define _lrotr(a,b) __rord((a), (b))
+
+/* Read flags register */
+extern __inline unsigned int
+__attribute__((__gnu_inline__, __always_inline__, __artificial__))
+__readeflags (void)
+{
+ return __builtin_ia32_readeflags_u32 ();
+}
+
+/* Write flags register */
+extern __inline void
+__attribute__((__gnu_inline__, __always_inline__, __artificial__))
+__writeeflags (unsigned int X)
+{
+ __builtin_ia32_writeeflags_u32 (X);
+}
+
#endif
#define _bit_scan_forward(a) __bsfd(a)
diff --git a/gcc/testsuite/gcc.target/i386/readeflags-1.c b/gcc/testsuite/gcc.target/i386/readeflags-1.c
new file mode 100644
index 0000000..6b2fa7e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/readeflags-1.c
@@ -0,0 +1,40 @@
+/* { dg-do run } */
+/* { dg-options "-O0" } */
+
+#include <x86intrin.h>
+
+#ifdef __x86_64__
+#define EFLAGS_TYPE unsigned long long int
+#else
+#define EFLAGS_TYPE unsigned int
+#endif
+
+static EFLAGS_TYPE
+readeflags_test (unsigned int a, unsigned int b)
+{
+ unsigned x = (a == b);
+ return __readeflags ();
+}
+
+int
+main ()
+{
+ EFLAGS_TYPE flags;
+
+ flags = readeflags_test (100, 100);
+
+ if ((flags & 1) != 0) /* Read CF */
+ abort ();
+
+ flags = readeflags_test (100, 101);
+
+ if ((flags & 1) == 0) /* Read CF */
+ abort ();
+
+#ifdef DEBUG
+ printf ("PASSED\n");
+#endif
+
+ return 0;
+}
+
diff --git a/gcc/testsuite/gcc.target/i386/writeeflags-1.c b/gcc/testsuite/gcc.target/i386/writeeflags-1.c
new file mode 100644
index 0000000..446840c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/writeeflags-1.c
@@ -0,0 +1,30 @@
+/* { dg-do run } */
+/* { dg-options "-O0" } */
+
+#include <x86intrin.h>
+
+#ifdef __x86_64__
+#define EFLAGS_TYPE unsigned long long int
+#else
+#define EFLAGS_TYPE unsigned int
+#endif
+
+int
+main ()
+{
+ EFLAGS_TYPE flags = 0xD7; /* 111010111b */
+
+ __writeeflags (flags);
+
+ flags = __readeflags ();
+
+ if ((flags & 0xFF) != 0xD7)
+ abort ();
+
+#ifdef DEBUG
+ printf ("PASSED\n");
+#endif
+
+ return 0;
+}
+