[PATCH v3 2/9] Introduce rtx_alloca, alloca_raw_REG and alloca_rtx_fmt_*

[Ilya Leoshkevich <iii@linux.ibm.com>]

One of the next patches in series needs to frequently pass short-lived
fake rtxes to the back-end in order to test its capabilities.  In order
to reduce the load on GC, it is beneficial to allocate these rtxes on
stack.

Provide the macro counterparts of gen_* functions required by the next
patch in series.

gcc/ChangeLog:

2019-08-27  Ilya Leoshkevich  <iii@linux.ibm.com>

	PR target/77918
	* emit-rtl.c (gen_raw_REG): Use init_raw_REG.
	(init_raw_REG): New function.
	* gengenrtl.c (gendef): Emit init_* functions and alloca_*
	macros.
	* rtl.c (rtx_alloc_stat_v): Use rtx_init.
	* rtl.h (rtx_init): New function.
	(rtx_alloca): New function.
	(init_raw_REG): New function.
	(alloca_raw_REG): New macro.
---
 gcc/emit-rtl.c  | 15 +++++++++---
 gcc/gengenrtl.c | 64 +++++++++++++++++++++++++++++++++++++------------
 gcc/rtl.c       |  7 +-----
 gcc/rtl.h       | 12 ++++++++++
 4 files changed, 74 insertions(+), 24 deletions(-)

diff --git a/gcc/emit-rtl.c b/gcc/emit-rtl.c
index a667cdab94e..ecfa3735bba 100644
--- a/gcc/emit-rtl.c
+++ b/gcc/emit-rtl.c
@@ -466,20 +466,29 @@ set_mode_and_regno (rtx x, machine_mode mode, unsigned int regno)
   set_regno_raw (x, regno, nregs);
 }
 
-/* Generate a new REG rtx.  Make sure ORIGINAL_REGNO is set properly, and
+/* Initialize a REG rtx.  Make sure ORIGINAL_REGNO is set properly, and
    don't attempt to share with the various global pieces of rtl (such as
    frame_pointer_rtx).  */
 
 rtx
-gen_raw_REG (machine_mode mode, unsigned int regno)
+init_raw_REG (rtx x, machine_mode mode, unsigned int regno)
 {
-  rtx x = rtx_alloc (REG MEM_STAT_INFO);
   set_mode_and_regno (x, mode, regno);
   REG_ATTRS (x) = NULL;
   ORIGINAL_REGNO (x) = regno;
   return x;
 }
 
+/* Generate a new REG rtx.  */
+
+rtx
+gen_raw_REG (machine_mode mode, unsigned int regno)
+{
+  rtx x = rtx_alloc (REG MEM_STAT_INFO);
+  init_raw_REG (x, mode, regno);
+  return x;
+}
+
 /* There are some RTL codes that require special attention; the generation
    functions do the raw handling.  If you add to this list, modify
    special_rtx in gengenrtl.c as well.  */
diff --git a/gcc/gengenrtl.c b/gcc/gengenrtl.c
index 5c78fabfb50..cd314a68a83 100644
--- a/gcc/gengenrtl.c
+++ b/gcc/gengenrtl.c
@@ -231,8 +231,7 @@ genmacro (int idx)
   puts (")");
 }
 
-/* Generate the code for the function to generate RTL whose
-   format is FORMAT.  */
+/* Generate the code for functions to generate RTL whose format is FORMAT.  */
 
 static void
 gendef (const char *format)
@@ -240,22 +239,18 @@ gendef (const char *format)
   const char *p;
   int i, j;
 
-  /* Start by writing the definition of the function name and the types
+  /* Write the definition of the init function name and the types
      of the arguments.  */
 
-  printf ("static inline rtx\ngen_rtx_fmt_%s_stat (RTX_CODE code, machine_mode mode", format);
+  puts ("static inline rtx");
+  printf ("init_rtx_fmt_%s (rtx rt, machine_mode mode", format);
   for (p = format, i = 0; *p != 0; p++)
     if (*p != '0')
       printf (",\n\t%sarg%d", type_from_format (*p), i++);
+  puts (")");
 
-  puts (" MEM_STAT_DECL)");
-
-  /* Now write out the body of the function itself, which allocates
-     the memory and initializes it.  */
+  /* Now write out the body of the init function itself.  */
   puts ("{");
-  puts ("  rtx rt;");
-  puts ("  rt = rtx_alloc (code PASS_MEM_STAT);\n");
-
   puts ("  PUT_MODE_RAW (rt, mode);");
 
   for (p = format, i = j = 0; *p ; ++p, ++i)
@@ -266,16 +261,55 @@ gendef (const char *format)
     else
       printf ("  %s (rt, %d) = arg%d;\n", accessor_from_format (*p), i, j++);
 
-  puts ("\n  return rt;\n}\n");
+  puts ("  return rt;\n}\n");
+
+  /* Write the definition of the gen function name and the types
+     of the arguments.  */
+
+  puts ("static inline rtx");
+  printf ("gen_rtx_fmt_%s_stat (RTX_CODE code, machine_mode mode", format);
+  for (p = format, i = 0; *p != 0; p++)
+    if (*p != '0')
+      printf (",\n\t%sarg%d", type_from_format (*p), i++);
+  puts (" MEM_STAT_DECL)");
+
+  /* Now write out the body of the function itself, which allocates
+     the memory and initializes it.  */
+  puts ("{");
+  puts ("  rtx rt;\n");
+
+  puts ("  rt = rtx_alloc (code PASS_MEM_STAT);");
+  printf ("  init_rtx_fmt_%s (rt, mode", format);
+  for (p = format, i = 0; *p != 0; p++)
+    if (*p != '0')
+      printf (", arg%d", i++);
+  puts (");\n");
+
+  puts ("  return rt;\n}\n");
+
+  /* Write the definition of gen macro.  */
+
   printf ("#define gen_rtx_fmt_%s(c, m", format);
   for (p = format, i = 0; *p != 0; p++)
     if (*p != '0')
-      printf (", p%i",i++);
-  printf (")\\\n        gen_rtx_fmt_%s_stat (c, m", format);
+      printf (", arg%d", i++);
+  printf (") \\\n  gen_rtx_fmt_%s_stat ((c), (m)", format);
   for (p = format, i = 0; *p != 0; p++)
     if (*p != '0')
-      printf (", p%i",i++);
+      printf (", (arg%d)", i++);
   printf (" MEM_STAT_INFO)\n\n");
+
+  /* Write the definition of alloca macro.  */
+
+  printf ("#define alloca_rtx_fmt_%s(c, m", format);
+  for (p = format, i = 0; *p != 0; p++)
+    if (*p != '0')
+      printf (", arg%d", i++);
+  printf (") \\\n  init_rtx_fmt_%s (rtx_alloca ((c)), (m)", format);
+  for (p = format, i = 0; *p != 0; p++)
+    if (*p != '0')
+      printf (", (arg%d)", i++);
+  printf (")\n\n");
 }
 
 /* Generate the documentation header for files we write.  */
diff --git a/gcc/rtl.c b/gcc/rtl.c
index d7b8e9877c3..0be52d38d93 100644
--- a/gcc/rtl.c
+++ b/gcc/rtl.c
@@ -219,12 +219,7 @@ rtx_alloc_stat_v (RTX_CODE code MEM_STAT_DECL, int extra)
   rtx rt = ggc_alloc_rtx_def_stat (RTX_CODE_SIZE (code) + extra
 				   PASS_MEM_STAT);
 
-  /* We want to clear everything up to the FLD array.  Normally, this
-     is one int, but we don't want to assume that and it isn't very
-     portable anyway; this is.  */
-
-  memset (rt, 0, RTX_HDR_SIZE);
-  PUT_CODE (rt, code);
+  rtx_init (rt, code);
 
   if (GATHER_STATISTICS)
     {
diff --git a/gcc/rtl.h b/gcc/rtl.h
index efb9b3ce40d..cf1547196f2 100644
--- a/gcc/rtl.h
+++ b/gcc/rtl.h
@@ -2933,6 +2933,15 @@ extern HOST_WIDE_INT get_stack_check_protect (void);
 
 /* In rtl.c */
 extern rtx rtx_alloc (RTX_CODE CXX_MEM_STAT_INFO);
+inline rtx
+rtx_init (rtx rt, RTX_CODE code)
+{
+  memset (rt, 0, RTX_HDR_SIZE);
+  PUT_CODE (rt, code);
+  return rt;
+}
+#define rtx_alloca(code) \
+  rtx_init ((rtx) alloca (RTX_CODE_SIZE ((code))), (code))
 extern rtx rtx_alloc_stat_v (RTX_CODE MEM_STAT_DECL, int);
 #define rtx_alloc_v(c, SZ) rtx_alloc_stat_v (c MEM_STAT_INFO, SZ)
 #define const_wide_int_alloc(NWORDS)				\
@@ -3797,7 +3806,10 @@ gen_rtx_INSN (machine_mode mode, rtx_insn *prev_insn, rtx_insn *next_insn,
 extern rtx gen_rtx_CONST_INT (machine_mode, HOST_WIDE_INT);
 extern rtx gen_rtx_CONST_VECTOR (machine_mode, rtvec);
 extern void set_mode_and_regno (rtx, machine_mode, unsigned int);
+extern rtx init_raw_REG (rtx, machine_mode, unsigned int);
 extern rtx gen_raw_REG (machine_mode, unsigned int);
+#define alloca_raw_REG(mode, regno) \
+  init_raw_REG (rtx_alloca (REG), (mode), (regno))
 extern rtx gen_rtx_REG (machine_mode, unsigned int);
 extern rtx gen_rtx_SUBREG (machine_mode, rtx, poly_uint64);
 extern rtx gen_rtx_MEM (machine_mode, rtx);
-- 
2.21.0