* [Bug optimization/9812] [3.3/3.4 regression] [m68k] ICE in extract_insn, at recog.c:2148
[not found] <20030223071600.9812.177840@bugs.debian.org>
2003-06-08 18:55 ` [Bug optimization/9812] [3.3/3.4 regression] [m68k] ICE in extract_insn, at recog.c:2148 pinskia@physics.uc.edu
2003-06-27 7:07 ` wilson at gcc dot gnu dot org
@ 2003-06-30 6:30 ` wilson at tuliptree dot org
2003-07-04 20:30 ` doko at cs dot tu-berlin dot de
` (4 subsequent siblings)
7 siblings, 0 replies; 8+ messages in thread
From: wilson at tuliptree dot org @ 2003-06-30 6:30 UTC (permalink / raw)
To: gcc-bugs
PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=9812
------- Additional Comments From wilson at tuliptree dot org 2003-06-30 06:30 -------
Subject: Re: [3.3/3.4 regression] [m68k] ICE in
extract_insn, at recog.c:2148
I googled the original testcase from 1995.
http://groups.google.com/groups?q=Andreas+Schwab+group:gnu.gcc.bug+group:gnu.gcc.bug+group:gnu.gcc.bug+group:gnu.gcc.bug+group:gnu.gcc.bug+group:gnu.gcc.bug+group:gnu.gcc.bug+group:gnu.gcc.bug&start=70&hl=en&lr=&ie=UTF-8&group=gnu.gcc.bug&selm=9511241005.AA04838%40lamothe.informatik.uni-dortmund.de&rnum=79
I don't know what I was thinking when I wrote that patch in 1995.
There is an obvious problem with the XFmode pattern here. It calls
force_const_mem during reload which is not safe. We either need to
reload the address ourselves, or not call it during reload. Fixing the
address outselves would require secondary reloads, so that seems
infeasible. So the obvious solution here is to guard the call against
reload_in_progress.
Fixing that makes the original LEGITIMATE_PIC_OPERAND_P patch
unnecessary. So we can remove the CONST_DOUBLE handling from that
macro. While doing that, I noticed there were about 6 duplicates of
that macro in various m68k files, so I deleted all but one. They used
to be different long ago, but those differences have all since
disappeared. Since m68k was the only place where mem_for_const_double
was used, we can now get rid of that function.
While looking at this, I noticed that there is a lot of confusion in the
XFmode patterns regarding constant support. Most of them disallow
constants in predicates and constraints, but have output templates that
handle emitting code for constants. This looks like it has been broken
since the beginning. I suspect that constant support was partially
disabled because of a bug, and then it was accidentally left in this
state forever. Or maybe someone copied the DFmode patterns and did a
poor job of editing them. I documented this in a comment.
With those changes, we now get unrecognized insns because reload thinks
that XFmode constants are OK, but we have no patterns at all that accept
XFmode constants. We fix that by rejecting them in LEGITIMATE_CONSTANT_P.
The resulting patch works for this testcase. I suspect we will get
better PIC FP code also, since we aren't needlessly forcing non-XFmode
constants into memory. This gives a medium size patch that will need a
lot of testing, and may not be appropriate for the gcc-3.3.1 release.
I can't really test this with m68k crosses, and I don't have access to
native m68k hardware.
Jim
2003-06-27 James E Wilson <wilson@tuliptree.org>
* rtl.h (mem_for_const_double): Delete prototype.
* varasm.c (mem_for_const_double): Delete function.
* config/m68k/hp320.h, config/m68k/linux.h, config/m68k/m68kelf.h,
config/m68k/m68kv4.h, config/m68k/netbsd-elf.h
(LEGITIMATE_PIC_OPERAND_P): Delete duplicate definitions.
* config/m68k/m68k.h (LEGITIMATE_CONSTANT_P): Disallow XFmode.
(LEGITIMATE_PIC_OPERAND_P): Delete CONST_DOUBLE tests.
* config/m68k/m68k.md (movxf): Add reload_in_progress guard. Add
comment about confused support for XFmode constants.
Index: rtl.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/rtl.h,v
retrieving revision 1.419
diff -p -r1.419 rtl.h
*** rtl.h 25 Jun 2003 03:45:13 -0000 1.419
--- rtl.h 27 Jun 2003 09:19:15 -0000
*************** extern void end_full_sequence PARAMS ((
*** 1494,1500 ****
/* In varasm.c */
extern rtx immed_double_const PARAMS ((HOST_WIDE_INT, HOST_WIDE_INT, enum machine_mode));
- extern rtx mem_for_const_double PARAMS ((rtx));
extern rtx force_const_mem PARAMS ((enum machine_mode, rtx));
/* In varasm.c */
--- 1494,1499 ----
Index: varasm.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/varasm.c,v
retrieving revision 1.368
diff -p -r1.368 varasm.c
*** varasm.c 25 Jun 2003 22:14:26 -0000 1.368
--- varasm.c 27 Jun 2003 09:19:18 -0000
*************** record_constant_rtx (mode, x)
*** 3033,3056 ****
return ptr;
}
\f
- /* Given a constant rtx X, return a MEM for the location in memory at which
- this constant has been placed. Return 0 if it not has been placed yet. */
-
- rtx
- mem_for_const_double (x)
- rtx x;
- {
- enum machine_mode mode = GET_MODE (x);
- struct constant_descriptor_rtx *desc;
-
- for (desc = const_rtx_hash_table[const_hash_rtx (mode, x)]; desc;
- desc = desc->next)
- if (compare_constant_rtx (mode, x, desc))
- return desc->rtl;
-
- return 0;
- }
-
/* Given a constant rtx X, make (or find) a memory constant for its value
and return a MEM rtx to refer to it in memory. */
--- 3033,3038 ----
Index: config/m68k/hp320.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/m68k/hp320.h,v
retrieving revision 1.26
diff -p -r1.26 hp320.h
*** config/m68k/hp320.h 19 Jun 2003 21:47:15 -0000 1.26
--- config/m68k/hp320.h 27 Jun 2003 09:19:20 -0000
*************** do { size_t i, limit = (SIZE); \
*** 555,572 ****
#endif /* not HPUX_ASM */
- /* In m68k svr4, a symbol_ref rtx can be a valid PIC operand if it is an
- operand of a function call. */
- #undef LEGITIMATE_PIC_OPERAND_P
- #define LEGITIMATE_PIC_OPERAND_P(X) \
- ((! symbolic_operand (X, VOIDmode) \
- && ! (GET_CODE (X) == CONST_DOUBLE && mem_for_const_double (X) != 0 \
- && GET_CODE (mem_for_const_double (X)) == MEM \
- && symbolic_operand (XEXP (mem_for_const_double (X), 0), \
- VOIDmode))) \
- || (GET_CODE (X) == SYMBOL_REF && SYMBOL_REF_FLAG (X)) \
- || PCREL_GENERAL_OPERAND_OK)
-
/* hpux8 and later have C++ compatible include files, so do not
pretend they are `extern "C"'. */
#define NO_IMPLICIT_EXTERN_C
--- 555,560 ----
Index: config/m68k/linux.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/m68k/linux.h,v
retrieving revision 1.33
diff -p -r1.33 linux.h
*** config/m68k/linux.h 7 Jun 2003 17:11:46 -0000 1.33
--- config/m68k/linux.h 27 Jun 2003 09:19:20 -0000
*************** do { \
*** 283,300 ****
? gen_rtx_REG ((MODE), 16) \
: gen_rtx_REG ((MODE), 0))
- /* In m68k svr4, a symbol_ref rtx can be a valid PIC operand if it is
- an operand of a function call. */
- #undef LEGITIMATE_PIC_OPERAND_P
- #define LEGITIMATE_PIC_OPERAND_P(X) \
- ((! symbolic_operand (X, VOIDmode) \
- && ! (GET_CODE (X) == CONST_DOUBLE && mem_for_const_double (X) != 0 \
- && GET_CODE (mem_for_const_double (X)) == MEM \
- && symbolic_operand (XEXP (mem_for_const_double (X), 0), \
- VOIDmode))) \
- || (GET_CODE (X) == SYMBOL_REF && SYMBOL_REF_FLAG (X)) \
- || PCREL_GENERAL_OPERAND_OK)
-
/* For m68k SVR4, structures are returned using the reentrant
technique. */
#undef PCC_STATIC_STRUCT_RETURN
--- 283,288 ----
Index: config/m68k/m68k.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/m68k/m68k.h,v
retrieving revision 1.90
diff -p -r1.90 m68k.h
*** config/m68k/m68k.h 19 Jun 2003 21:47:15 -0000 1.90
--- config/m68k/m68k.h 27 Jun 2003 09:19:22 -0000
*************** __transfer_from_trampoline () \
*** 997,1003 ****
/* Nonzero if the constant value X is a legitimate general operand.
It is given that X satisfies CONSTANT_P or is a CONST_DOUBLE. */
! #define LEGITIMATE_CONSTANT_P(X) 1
/* Nonzero if the constant value X is a legitimate general operand
when generating PIC code. It is given that flag_pic is on and
--- 997,1003 ----
/* Nonzero if the constant value X is a legitimate general operand.
It is given that X satisfies CONSTANT_P or is a CONST_DOUBLE. */
! #define LEGITIMATE_CONSTANT_P(X) (GET_MODE (X) != XFmode)
/* Nonzero if the constant value X is a legitimate general operand
when generating PIC code. It is given that flag_pic is on and
*************** __transfer_from_trampoline () \
*** 1014,1025 ****
#endif
#define LEGITIMATE_PIC_OPERAND_P(X) \
! ((! symbolic_operand (X, VOIDmode) \
! && ! (GET_CODE (X) == CONST_DOUBLE && mem_for_const_double (X) != 0 \
! && GET_CODE (mem_for_const_double (X)) == MEM \
! && symbolic_operand (XEXP (mem_for_const_double (X), 0), \
! VOIDmode))) \
! || (GET_CODE (X) == SYMBOL_REF && SYMBOL_REF_FLAG (X)) \
|| PCREL_GENERAL_OPERAND_OK)
/* The macros REG_OK_FOR..._P assume that the arg is a REG rtx
--- 1014,1021 ----
#endif
#define LEGITIMATE_PIC_OPERAND_P(X) \
! (! symbolic_operand (X, VOIDmode) \
! || (GET_CODE (X) == SYMBOL_REF && SYMBOL_REF_FLAG (X)) \
|| PCREL_GENERAL_OPERAND_OK)
/* The macros REG_OK_FOR..._P assume that the arg is a REG rtx
Index: config/m68k/m68k.md
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/m68k/m68k.md,v
retrieving revision 1.59
diff -p -r1.59 m68k.md
*** config/m68k/m68k.md 12 Jun 2003 21:57:31 -0000 1.59
--- config/m68k/m68k.md 27 Jun 2003 09:40:12 -0000
***************
*** 999,1025 ****
"TARGET_5200"
"* return output_move_double (operands);")
(define_expand "movxf"
[(set (match_operand:XF 0 "nonimmediate_operand" "")
(match_operand:XF 1 "general_operand" ""))]
""
"
{
! if (CONSTANT_P (operands[1]))
{
! operands[1] = force_const_mem (XFmode, operands[1]);
! if (! memory_address_p (XFmode, XEXP (operands[1], 0))
! && ! reload_in_progress)
! operands[1] = adjust_address (operands[1], XFmode, 0);
! }
! if (flag_pic && TARGET_PCREL && ! reload_in_progress)
! {
! /* Don't allow writes to memory except via a register;
! the m68k doesn't consider PC-relative addresses to be writable. */
! if (GET_CODE (operands[0]) == MEM
! && symbolic_operand (XEXP (operands[0], 0), SImode))
! operands[0] = gen_rtx (MEM, XFmode,
! force_reg (SImode, XEXP (operands[0], 0)));
}
}")
--- 999,1033 ----
"TARGET_5200"
"* return output_move_double (operands);")
+ ;; ??? The XFmode patterns are schizophrenic about whether constants are
+ ;; allowed. Most but not all have predicates and constraint that disallow
+ ;; constants. Most but not all have output templates that handle constants.
+ ;; See also LEGITIMATE_CONSTANT_P.
+
(define_expand "movxf"
[(set (match_operand:XF 0 "nonimmediate_operand" "")
(match_operand:XF 1 "general_operand" ""))]
""
"
{
! /* We can't rewrite operands during reload. */
! if (! reload_in_progress)
{
! if (CONSTANT_P (operands[1]))
! {
! operands[1] = force_const_mem (XFmode, operands[1]);
! if (! memory_address_p (XFmode, XEXP (operands[1], 0)))
! operands[1] = adjust_address (operands[1], XFmode, 0);
! }
! if (flag_pic && TARGET_PCREL)
! {
! /* Don't allow writes to memory except via a register; the
! m68k doesn't consider PC-relative addresses to be writable. */
! if (GET_CODE (operands[0]) == MEM
! && symbolic_operand (XEXP (operands[0], 0), SImode))
! operands[0] = gen_rtx (MEM, XFmode,
! force_reg (SImode, XEXP (operands[0], 0)));
! }
}
}")
Index: config/m68k/m68kelf.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/m68k/m68kelf.h,v
retrieving revision 1.18
diff -p -r1.18 m68kelf.h
*** config/m68k/m68kelf.h 12 May 2003 09:51:29 -0000 1.18
--- config/m68k/m68kelf.h 27 Jun 2003 09:19:30 -0000
*************** extern int switch_table_difference_label
*** 246,261 ****
#undef ASM_OUTPUT_BEFORE_CASE_LABEL
#define ASM_OUTPUT_BEFORE_CASE_LABEL(FILE,PREFIX,NUM,TABLE) \
fprintf ((FILE), "%s&%d\n", SWBEG_ASM_OP, XVECLEN (PATTERN (TABLE), 1));
-
- /* In m68k svr4, a symbol_ref rtx can be a valid PIC operand if it is an
- operand of a function call. */
- #undef LEGITIMATE_PIC_OPERAND_P
-
- #define LEGITIMATE_PIC_OPERAND_P(X) \
- (! symbolic_operand (X, VOIDmode) \
- || (GET_CODE (X) == SYMBOL_REF && SYMBOL_REF_FLAG (X)) \
- || PCREL_GENERAL_OPERAND_OK)
-
/* end of stuff from m68kv4.h */
#undef SGS_CMP_ORDER
--- 246,251 ----
Index: config/m68k/m68kv4.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/m68k/m68kv4.h,v
retrieving revision 1.22
diff -p -r1.22 m68kv4.h
*** config/m68k/m68kv4.h 17 May 2003 21:57:38 -0000 1.22
--- config/m68k/m68kv4.h 27 Jun 2003 09:19:30 -0000
*************** int switch_table_difference_label_flag;
*** 277,294 ****
#define ASM_OUTPUT_BEFORE_CASE_LABEL(FILE,PREFIX,NUM,TABLE) \
fprintf ((FILE), "%s&%d\n", SWBEG_ASM_OP, XVECLEN (PATTERN (TABLE), 1));
- /* In m68k svr4, a symbol_ref rtx can be a valid PIC operand if it is an
- operand of a function call. */
- #undef LEGITIMATE_PIC_OPERAND_P
- #define LEGITIMATE_PIC_OPERAND_P(X) \
- ((! symbolic_operand (X, VOIDmode) \
- && ! (GET_CODE (X) == CONST_DOUBLE && mem_for_const_double (X) != 0 \
- && GET_CODE (mem_for_const_double (X)) == MEM \
- && symbolic_operand (XEXP (mem_for_const_double (X), 0), \
- VOIDmode))) \
- || (GET_CODE (X) == SYMBOL_REF && SYMBOL_REF_FLAG (X)) \
- || PCREL_GENERAL_OPERAND_OK)
-
/* Output assembler code for a block containing the constant parts
of a trampoline, leaving space for the variable parts. */
--- 277,282 ----
Index: config/m68k/netbsd-elf.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/m68k/netbsd-elf.h,v
retrieving revision 1.14
diff -p -r1.14 netbsd-elf.h
*** config/m68k/netbsd-elf.h 3 Jun 2003 09:06:54 -0000 1.14
--- config/m68k/netbsd-elf.h 27 Jun 2003 09:19:30 -0000
*************** while (0)
*** 385,404 ****
#define BIGGEST_ALIGNMENT 64
- /* In m68k svr4, a symbol_ref rtx can be a valid PIC operand if it is
- an operand of a function call. */
-
- #undef LEGITIMATE_PIC_OPERAND_P
- #define LEGITIMATE_PIC_OPERAND_P(X) \
- ((! symbolic_operand (X, VOIDmode) \
- && ! (GET_CODE (X) == CONST_DOUBLE && mem_for_const_double (X) \
- && GET_CODE (mem_for_const_double (X)) == MEM \
- && symbolic_operand (XEXP (mem_for_const_double (X), 0), \
- VOIDmode))) \
- || (GET_CODE (X) == SYMBOL_REF && SYMBOL_REF_FLAG (X)) \
- || PCREL_GENERAL_OPERAND_OK)
-
-
/* For m68k SVR4, structures are returned using the reentrant
technique. */
--- 385,390 ----
^ permalink raw reply [flat|nested] 8+ messages in thread