Re: ada/4848: Internal compiler error in instantiate_virtual_regs_1, at function.c:3904

["Unruh, Erwin" <Erwin dot Unruh at fujitsu-siemens dot com>]

Hello,

I have found a similar problem a few days ago. I got an abort at exactly the
same place, but in a different, yet unpublished port.

My reasoning was:

I found an inconsistency between recog.c and genrecog.c. It is related to the
handling of ADDRESSOF.

In recog.c:register_operand a rtx with code ADDRESSOF is allowed. In the
variable genrecog.c:preds however there is no mentioning of this code.

But instruction recognizing is used when such codes are still alive. One such
point is instantiate_virtual_regs.

I am working on a new port and got hit by

(insn 12 7 13 (set (reg:CC 100 %icc)
        (compare:CC (addressof:SI (reg/v:SI 108) 107 374bc8)
            (reg/f:SI 102 virtual-stack-vars))) -1 (nil)
    (nil))

when compiling a small program with optimization:

        void f() { long a, b[6]; a = ( &a < b ); }

When replacing the virtual-stack-vars register the recognition of the
instruction failed because the compare required two registers. The stack grows
upward so a local variable could be at offset 0 from that register. 

I made some corrections in genrecog.c and realized that the definition of
PREDICATE_CODES has to be checked in all ports.

        Erwin

Index: genrecog.c
===================================================================
RCS file: /usr/local/cvscpp/archive/gcc/gcc/genrecog.c,v
retrieving revision 1.1.1.1
diff -u -c -3 -p -r1.1.1.1 genrecog.c
*** genrecog.c  2001/03/28 08:57:09     1.1.1.1
--- genrecog.c  2001/11/07 13:46:16
*************** static struct pred_table
*** 186,205 ****
    RTX_CODE codes[NUM_RTX_CODE];
  } preds[] = {
    {"general_operand", {CONST_INT, CONST_DOUBLE, CONST, SYMBOL_REF,
!                      LABEL_REF, SUBREG, REG, MEM}},
  #ifdef PREDICATE_CODES
    PREDICATE_CODES
  #endif
    {"address_operand", {CONST_INT, CONST_DOUBLE, CONST, SYMBOL_REF,
!                      LABEL_REF, SUBREG, REG, MEM, PLUS, MINUS, MULT}},
!   {"register_operand", {SUBREG, REG}},
!   {"pmode_register_operand", {SUBREG, REG}},
    {"scratch_operand", {SCRATCH, REG}},
    {"immediate_operand", {CONST_INT, CONST_DOUBLE, CONST, SYMBOL_REF,
                         LABEL_REF}},
    {"const_int_operand", {CONST_INT}},
    {"const_double_operand", {CONST_INT, CONST_DOUBLE}},
!   {"nonimmediate_operand", {SUBREG, REG, MEM}},
    {"nonmemory_operand", {CONST_INT, CONST_DOUBLE, CONST, SYMBOL_REF,
                         LABEL_REF, SUBREG, REG}},
    {"push_operand", {MEM}},
--- 186,205 ----
    RTX_CODE codes[NUM_RTX_CODE];
  } preds[] = {
    {"general_operand", {CONST_INT, CONST_DOUBLE, CONST, SYMBOL_REF,
!                      LABEL_REF, SUBREG, REG, MEM, ADDRESSOF}},
  #ifdef PREDICATE_CODES
    PREDICATE_CODES
  #endif
    {"address_operand", {CONST_INT, CONST_DOUBLE, CONST, SYMBOL_REF,
!                      LABEL_REF, SUBREG, REG, MEM, PLUS, MINUS, MULT, ADDRESSO>F}},
!   {"register_operand", {SUBREG, REG, ADDRESSOF}},
!   {"pmode_register_operand", {SUBREG, REG, ADDRESSOF}},
    {"scratch_operand", {SCRATCH, REG}},
    {"immediate_operand", {CONST_INT, CONST_DOUBLE, CONST, SYMBOL_REF,
                         LABEL_REF}},
    {"const_int_operand", {CONST_INT}},
    {"const_double_operand", {CONST_INT, CONST_DOUBLE}},
!   {"nonimmediate_operand", {SUBREG, REG, MEM, ADDRESSOF}},
    {"nonmemory_operand", {CONST_INT, CONST_DOUBLE, CONST, SYMBOL_REF,
                         LABEL_REF, SUBREG, REG}},
    {"push_operand", {MEM}},
*************** static struct pred_table
*** 210,216 ****
                           UNORDERED, ORDERED, UNEQ, UNGE, UNGT, UNLE,
                           UNLT, LTGT}},
    {"mode_independent_operand", {CONST_INT, CONST_DOUBLE, CONST, SYMBOL_REF,
!                               LABEL_REF, SUBREG, REG, MEM}}
  };

  #define NUM_KNOWN_PREDS ARRAY_SIZE (preds)
--- 210,216 ----
                           UNORDERED, ORDERED, UNEQ, UNGE, UNGT, UNLE,
                           UNLT, LTGT}},
    {"mode_independent_operand", {CONST_INT, CONST_DOUBLE, CONST, SYMBOL_REF,
!                               LABEL_REF, SUBREG, REG, MEM, ADDRESSOF}}
  };

  #define NUM_KNOWN_PREDS ARRAY_SIZE (preds)

Erwin Unruh, Fujitsu Siemens Computers, C/C++ compiler group