Re: optimization/7124: -O2 -march=athlon produces ICE

[Reichelt <reichelt@igpm.rwth-aachen.de>]

The following reply was made to PR optimization/7124; it has been noted by GNATS.

From: Reichelt <reichelt@igpm.rwth-aachen.de>
To: gcc-gnats@gcc.gnu.org, perrin@MSLI.com, gcc-bugs@gcc.gnu.org,
        nobody@gcc.gnu.org
Cc:  
Subject: Re: optimization/7124: -O2 -march=athlon produces ICE
Date: Wed, 26 Jun 2002 17:46:42 +0200

 Hi,
 
 the test example can be reduced a little, so that it still crashes
 the compiler:
 
 -------------------------snip here-------------------------------
 void foo ()
 {
     struct { float x, y; } c, *cp;
     static float           z;
 
     while (1)
     {
         c.y = cp->y + cp->y;
         z   = c.y + 1.0;
     }
 }
 -------------------------snip here-------------------------------
 
 Just compile this with "gcc -O -march=athlon -c" on a i686-pc-linux-gnu
 box. With gcc 3.1 one gets:
 
 clacrt.c: In function `foo':
 clacrt.c:11: Internal compiler error in ix86_secondary_memory_needed, at config/i386/i386.c:12251
 Please submit a full bug report, [etc.]
 
 With the main trunk one gets:
 
 clacrt.c: In function `foo':
 clacrt.c:11: error: insn does not satisfy its constraints:
 (insn 58 23 57 1 (nil) (set (reg:SF 30 emm1)
         (reg:SF 8 st(0))) 90 {*movsf_1} (nil)
     (nil))
 clacrt.c:11: internal compiler error: Internal compiler error in reload_cse_simplify_operands, at reload1.c:8311
 Please submit a full bug report, [etc.]
 
 However, if one changes the position of x and y in the struct one gets:
 
 clacrt.c: In function `foo':
 clacrt.c:11: error: unable to find a register to spill in class `FLOAT_REGS'
 clacrt.c:11: error: this is the insn:
 (insn 23 22 25 1 0x4018cfc0 (set (subreg:SF (reg/v:DI 29 rmm0 [58]) 0)
         (plus:SF (reg:SF 8 st(0) [61])
             (mem/s/j:SF (reg/v/f:SI 0 eax [59]) [0 <variable>.y+0 S4 A32]))) 546 {*fop_sf_comm_nosse} (insn_list 21 (nil))
     (expr_list:REG_DEAD (reg:SF 8 st(0) [61])
         (nil)))
 clacrt.c:11: internal compiler error: Internal compiler error in spill_failure, at reload1.c:1908
 Please submit a full bug report, [etc.]
 
 The bug is a regression from gcc 3.0.x.
 
 Greetings,
 Volker Reichelt
 
 http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=7124