------- Comment #3 from vmakarov at redhat dot com  2009-03-25 21:05 -------
Thanks for reporting this.

The compiler is broken on gcc_assert in the following code

+                 else if ((code == PRE_INC || code == PRE_DEC
+                           || code == POST_INC || code == POST_DEC))
+                   {
+                     int in_hard_regno;
+                     int in_regno = REGNO (XEXP (in_reg, 0));
+
+                     if (reg_last_reload_reg[in_regno] != NULL_RTX)
+                       {
+                         in_hard_regno = REGNO
(reg_last_reload_reg[in_regno]);
+                         gcc_assert (TEST_HARD_REG_BIT (reg_reloaded_valid,
+                                                        in_hard_regno));
+                         for (x = old_prev ? NEXT_INSN (old_prev) : insn;
+                              x != old_next;
+                              x = NEXT_INSN (x))
+                           if (x == reg_reloaded_insn[in_hard_regno])
+                             break;
+                         /* If for some reasons, we didn't set up
+                            reg_last_reload_reg in this insn,
+                            invalidate inheritance from previous
+                            insns for the incremented/decremented
+                            register.  Such registers will be not in
+                            reg_has_output_reload.  */
+                         if (x == old_next)
+                           forget_old_reloads_1 (XEXP (in_reg, 0),
+                                                 NULL_RTX, NULL);
+                       }
+                   }

Here in_regno is 191 and in_hard_regno is 8.  This code is executed
after emit_insn_reloads which invalidates hard register 8 when
processing reload #5 of the current insn.  I've overlooked this
possibility in my patch for PR37514

http://gcc.gnu.org/ml/gcc-patches/2008-11/msg01424.html

reg_reloaded_valid should be checked for reg_reloaded_insn validity
but not as gcc_assert.  I'll send a new patch solving the problem soon.


(insn 411 1161 1160 17
/tmp/x144980/gcc/gcc/testsuite/gcc.c-torture/execute/stdarg-3.c:144 (set
(mem/s/c:SI (post_inc:SI (reg/f:SI 192)) [10 S4 A8])
        (mem/s/c:SI (post_inc:SI (reg/f:SI 191)) [10 a3+4 S4 A16])) 38
{*movsi_internal} (expr_list:REG_INC (reg/f:SI 191)
        (expr_list:REG_INC (reg/f:SI 192)
            (nil))))

Reloads for insn # 411
Reload 0: reload_in (SI) = (plus:SI (reg/f:SI 14 sp)
                                                    (const_int 104 [0x68]))
        GENERAL_REGS, RELOAD_FOR_OPERAND_ADDRESS (opnum = 0), can't combine
        reload_in_reg: (plus:SI (reg/f:SI 14 sp)
                                                    (const_int 104 [0x68]))
        reload_reg_rtx: (reg:SI 9 r9)
Reload 1: reload_in (SI) = (post_inc:SI (mem/c:SI (plus:SI (reg/f:SI 14 sp)
                                                            (const_int 104
[0x68])) [11 %sfp+-280 S4 A8]))
        reload_out (SI) = (post_inc:SI (mem/c:SI (plus:SI (reg/f:SI 14 sp)
                                                            (const_int 104
[0x68])) [11 %sfp+-280 S4 A8]))
        GENERAL_REGS, RELOAD_FOR_OPERAND_ADDRESS (opnum = 0), inc by 4, can't
combine
        reload_in_reg: (post_inc:SI (reg/f:SI 192))
        reload_reg_rtx: (reg:SI 6 r6)
Reload 2: reload_in (SI) = (plus:SI (reg/f:SI 14 sp)
                                                    (const_int 100 [0x64]))
        GENERAL_REGS, RELOAD_FOR_INPUT_ADDRESS (opnum = 1), can't combine
        reload_in_reg: (plus:SI (reg/f:SI 14 sp)
                                                    (const_int 100 [0x64]))
        reload_reg_rtx: (reg:SI 9 r9)
Reload 3: reload_in (SI) = (post_inc:SI (mem/c:SI (plus:SI (reg/f:SI 14 sp)
                                                            (const_int 100
[0x64])) [11 %sfp+-284 S4 A8]))
        reload_out (SI) = (post_inc:SI (mem/c:SI (plus:SI (reg/f:SI 14 sp)
                                                            (const_int 100
[0x64])) [11 %sfp+-284 S4 A8]))
        GENERAL_REGS, RELOAD_FOR_INPUT_ADDRESS (opnum = 1), inc by 4, can't
combine
        reload_in_reg: (post_inc:SI (reg/f:SI 191))
        reload_reg_rtx: (reg:SI 8 r8)
Reload 4: reload_out (SI) = (mem/s/c:SI (post_inc:SI (reg/f:SI 192)) [10 S4
A8])
        NO_REGS, RELOAD_FOR_OUTPUT (opnum = 0), optional
        reload_out_reg: (mem/s/c:SI (post_inc:SI (reg/f:SI 192)) [10 S4 A8])
Reload 5: reload_in (SI) = (mem/s/c:SI (post_inc:SI (reg/f:SI 191)) [10 a3+4 S4
A16])
        GENERAL_REGS, RELOAD_FOR_INPUT (opnum = 1)
        reload_in_reg: (mem/s/c:SI (post_inc:SI (reg/f:SI 191)) [10 a3+4 S4
A16])
        reload_reg_rtx: (reg:SI 8 r8)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39522

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