Re: Silly gcc bugs

["Maciej W. Rozycki" <macro%linux-mips.org@localhost>]

On Mon, 15 Feb 2016, Martin Husemann wrote:

> >  I hope this was the last issue, but please do let me know even if not.
> 
> Unfortunately the new compiler fails at various places like this:
> 
> #   compile  libgmp/hgcd2_jacobi.o
> /usr/tools/bin/vax--netbsdelf-gcc -O2 -pipe   -std=gnu99   -Werror   -g -Wno-stack-protector  --sysroot=/hosts/vax -I. -I/usr/src/external/lgpl3/gmp/lib/libgmp/../../dist -I/usr/src/external/lgpl3/gmp/lib/libgmp/arch/vax  -D__GMP_WITHIN_GMP -DHAVE_CONFIG_H  -c    /usr/src/external/lgpl3/gmp/lib/libgmp/../../dist/mpn/generic/hgcd2_jacobi.c -o hgcd2_jacobi.o
> (symbol_ref:SI ("__gmp_jacobi_table") [flags 0x40] <var_decl 0x7f7ff6c99980 __gmp_jacobi_table>)
> /usr/src/external/lgpl3/gmp/lib/libgmp/../../dist/mpn/generic/hgcd2_jacobi.c: In function '__gmpn_hgcd2_jacobi':
> /usr/src/external/lgpl3/gmp/lib/libgmp/../../dist/mpn/generic/hgcd2_jacobi.c:356:1: internal compiler error: output_operand: symbol used as immediate operand
>  }
>  ^
> 
> Let me know if you need any intermediate files or whatever (this is your patch
> applied to 4.8.5 as in our current tree in the gcc.old directory)

 Right, an immediate can be symbolic and on the VAX target this is a no-no 
when producing PIC code.  Also control shouldn't have fallen through to 
this case.

 Fixed thus and verified with this small test case:

extern char ptr[];

char *add(int x, int y)
{
	asm("" : "+r" (x), "+r" (y));

	return ptr + x + 4 * y;
}

2016-02-15  Maciej W. Rozycki  <macro%linux-mips.org@localhost>

	gcc/
	* config/vax/vax.c (print_operand): Add the `o' operand code.
	* config/vax/predicates.md (nonsymbolic_imm_operand): New 
	predicate.
	(const_248_operand): Likewise.
	* config/vax/vax.md (*addsi3_mova, *addsi4_mova): New insns.

  Maciej

gcc-4.1.2-vax-mova.patch
Index: gcc-4.1.2/gcc/config/vax/predicates.md
===================================================================
--- gcc-4.1.2.orig/gcc/config/vax/predicates.md
+++ gcc-4.1.2/gcc/config/vax/predicates.md
@@ -50,6 +50,11 @@
 	    (not (match_operand 0 "symbolic_operand")))
        (match_operand 0 "general_operand" "")))
 
+(define_predicate "nonsymbolic_imm_operand"
+  (and (ior (match_test "!flag_pic")
+	    (not (match_operand 0 "symbolic_operand")))
+       (match_operand 0 "immediate_operand" "")))
+
 (define_predicate "external_memory_operand"
    (match_code "mem")
 {
@@ -102,3 +107,11 @@
    (and (match_code "const_int,const_double,subreg,reg,mem")
 	(and (match_operand:DI 0 "general_operand" "")
 	     (not (match_operand:DI 0 "illegal_addsub_di_memory_operand")))))
+
+;; Match 2, 4, or 8.  Used for mova multiplicands.
+(define_predicate "const_248_operand"
+   (match_code "const_int")
+{
+  HOST_WIDE_INT i = INTVAL (op);
+  return i == 2 || i == 4 || i == 8;
+})
Index: gcc-4.1.2/gcc/config/vax/vax.c
===================================================================
--- gcc-4.1.2.orig/gcc/config/vax/vax.c
+++ gcc-4.1.2/gcc/config/vax/vax.c
@@ -425,6 +425,8 @@ print_operand (FILE *file, rtx x, int co
     fputs (REGISTER_PREFIX, file);
   else if (code == 'C')
     fputs (rev_cond_name (x), file);
+  else if (code == 'o' && CONSTANT_P (x))
+    output_addr_const (file, x);
   else if (code == 'D' && CONST_INT_P (x) && INTVAL (x) < 0)
     fprintf (file, "$" NEG_HWI_PRINT_HEX16, INTVAL (x));
   else if (code == 'P' && CONST_INT_P (x))
Index: gcc-4.1.2/gcc/config/vax/vax.md
===================================================================
--- gcc-4.1.2.orig/gcc/config/vax/vax.md
+++ gcc-4.1.2/gcc/config/vax/vax.md
@@ -405,6 +405,54 @@
 		 (match_operand:DI 2 "general_operand" "Fsro,Fs")))]
   "!TARGET_QMATH"
   "* return vax_output_int_add (insn, operands, DImode);")
+
+;; Scaled additions using mova, needed for virtual register instantiation.
+(define_insn "*addsi3_mova"
+  [(set (match_operand:SI 0 "nonimmediate_operand" "=g")
+	(plus:SI (mult:SI (match_operand:SI 1 "register_operand" "r")
+			  (match_operand 2 "const_248_operand" "n"))
+		 (match_operand:SI 3 "register_operand" "r")))]
+  ""
+  "*
+{
+  int i = INTVAL (operands[2]);
+
+  switch (i)
+    {
+    case 2:
+      return \"movaw (%3)[%1],%0\";
+    case 4:
+      return \"moval (%3)[%1],%0\";
+    case 8:
+      return \"movaq (%3)[%1],%0\";
+    default:
+      gcc_unreachable ();
+    }
+}")
+
+(define_insn "*addsi4_mova"
+  [(set (match_operand:SI 0 "nonimmediate_operand" "=g")
+	(plus:SI (plus:SI (mult:SI (match_operand:SI 1 "register_operand" "r")
+				   (match_operand 2 "const_248_operand" "n"))
+			  (match_operand:SI 3 "register_operand" "r"))
+		 (match_operand:SI 4 "nonsymbolic_imm_operand" "nT")))]
+  ""
+  "*
+{
+  int i = INTVAL (operands[2]);
+
+  switch (i)
+    {
+    case 2:
+      return \"movaw %o4(%3)[%1],%0\";
+    case 4:
+      return \"moval %o4(%3)[%1],%0\";
+    case 8:
+      return \"movaq %o4(%3)[%1],%0\";
+    default:
+      gcc_unreachable ();
+    }
+}")
 
 ;;- All kinds of subtract instructions.