Append target/optimize attr to the current cmdline.

gcc/c-family/ChangeLog:

	* c-common.c (parse_optimize_options): Combine optimize
	options with what was provided on the command line.

gcc/ChangeLog:

	* toplev.c (toplev::main): Save decoded optimization options.
	* toplev.h (save_opt_decoded_options): New.
	* doc/extend.texi: Be more clear about optimize and target
	attributes.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/avx512er-vrsqrt28ps-3.c: Disable fast math.
	* gcc.target/i386/avx512er-vrsqrt28ps-5.c: Likewise.
	* gcc.target/i386/attr-optimize.c: New test.

gcc/c-family/c-common.c

@@ -5904,9 +5904,22 @@ parse_optimize_options (tree args, bool attr_p)
       j++;
     }
   decoded_options_count = j;
-  /* And apply them.  */
+
+  /* Merge the decoded options with save_decoded_options.  */
+  unsigned save_opt_count = save_opt_decoded_options.length ();
+  unsigned merged_decoded_options_count
+    = save_opt_count + decoded_options_count;
+  cl_decoded_option *merged_decoded_options
+    = XNEWVEC (cl_decoded_option, merged_decoded_options_count);
+
+  for (unsigned i = 0; i < save_opt_count; ++i)
+    merged_decoded_options[i] = save_opt_decoded_options[i];
+  for (unsigned i = 0; i < decoded_options_count; ++i)
+    merged_decoded_options[save_opt_count + i] = decoded_options[i];
+
+   /* And apply them.  */
   decode_options (&global_options, &global_options_set,
-		  decoded_options, decoded_options_count,
+		  merged_decoded_options, merged_decoded_options_count,
 		  input_location, global_dc, NULL);
   free (decoded_options);
 

gcc/doc/extend.texi

@@ -3663,7 +3663,10 @@ take function pointer arguments.
 @cindex @code{optimize} function attribute
 The @code{optimize} attribute is used to specify that a function is to
 be compiled with different optimization options than specified on the
-command line.  Valid arguments are constant non-negative integers and
+command line.  The optimize attribute arguments of a function behave
+behave as if appended to the command-line.
+
+Valid arguments are constant non-negative integers and
 strings.  Each numeric argument specifies an optimization @var{level}.
 Each @var{string} argument consists of one or more comma-separated
 substrings.  Each substring that begins with the letter @code{O} refers
@@ -3867,7 +3870,8 @@ This attribute prevents stack protection code for the function.
 Multiple target back ends implement the @code{target} attribute
 to specify that a function is to
 be compiled with different target options than specified on the
-command line.  One or more strings can be provided as arguments.
+command line.  The original target command-line options are ignored.
+One or more strings can be provided as arguments.
 Each string consists of one or more comma-separated suffixes to
 the @code{-m} prefix jointly forming the name of a machine-dependent
 option.  @xref{Submodel Options,,Machine-Dependent Options}.

gcc/testsuite/gcc.target/i386/attr-optimize.c

@@ -0,0 +1,24 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-O1 -ftree-slp-vectorize -march=znver1 -fdump-tree-optimized" } */
+
+/* Use -O2, but -ftree-slp-vectorize option should be preserved and used.  */
+#pragma GCC optimize "-O2"
+
+typedef struct {
+  long n[4];
+} secp256k1_fe;
+
+void *a;
+int c;
+static void
+fn1(secp256k1_fe *p1, int p2)
+{
+  p1->n[0] = p1->n[1] = p2;
+}
+void
+fn2()
+{
+  fn1(a, !c);
+}
+
+/* { dg-final { scan-tree-dump { MEM <vector\(2\) long int> \[[^]]*\] = } "optimized" } } */

gcc/testsuite/gcc.target/i386/avx512er-vrsqrt28ps-3.c

@@ -8,7 +8,7 @@
 #define MAX 1000
 #define EPS 0.00001
 
-__attribute__ ((noinline, optimize (1)))
+__attribute__ ((noinline, optimize (1, "-fno-fast-math")))
 void static
 compute_rsqrt_ref (float *a, float *r)
 {

gcc/testsuite/gcc.target/i386/avx512er-vrsqrt28ps-5.c

@@ -8,7 +8,7 @@
 #define MAX 1000
 #define EPS 0.00001
 
-__attribute__ ((noinline, optimize (1)))
+__attribute__ ((noinline, optimize (1, "-fno-fast-math")))
 void static
 compute_sqrt_ref (float *a, float *r)
 {

gcc/toplev.c

@@ -121,6 +121,9 @@ static bool no_backend;
 struct cl_decoded_option *save_decoded_options;
 unsigned int save_decoded_options_count;
 
+/* Vector of saved Optimization decoded command line options.  */
+auto_vec<cl_decoded_option> save_opt_decoded_options;
+
 /* Used to enable -fvar-tracking, -fweb and -frename-registers according
    to optimize in process_options ().  */
 #define AUTODETECT_VALUE 2
@@ -2334,6 +2337,11 @@ toplev::main (int argc, char **argv)
 						&save_decoded_options,
 						&save_decoded_options_count);
 
+  /* Save Optimization decoded options.  */
+  for (unsigned i = 0; i < save_decoded_options_count; ++i)
+    if (cl_options[save_decoded_options[i].opt_index].flags & CL_OPTIMIZATION)
+      save_opt_decoded_options.safe_push (save_decoded_options[i]);
+
   /* Perform language-specific options initialization.  */
   lang_hooks.init_options (save_decoded_options_count, save_decoded_options);
 

gcc/toplev.h

@@ -23,6 +23,7 @@ along with GCC; see the file COPYING3.  If not see
 /* Decoded options, and number of such options.  */
 extern struct cl_decoded_option *save_decoded_options;
 extern unsigned int save_decoded_options_count;
+extern auto_vec<cl_decoded_option> save_opt_decoded_options;
 
 class timer;