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[Bug target/35135] unable to find a register to spill in class ‘GENERAL_REGS’ with global registers


------- Comment #8 from rob1weld at aol dot com  2009-01-31 21:01 -------
Sometimes you can skirt around the "GENERAL_REGS" error with other options.

When I use "-O0", "-O1", "-O2", "-O3", "-Os" I get different results.

Using "-O0" produces no screen output _or_ compiled file (thus it 'looks'
as though it compiled OK).


# gcc -ffloat-store -msse3 -mssse3 -m3dnow -msse4.1 -mfpmath=sse,387 
-I./../arch/386 -I. -Wall -O0 -fomit-frame-pointer -fforce-addr -DHAVE_CONFIG_H
-DFORCE_LL -DFORCE_REG
-DDEFAULTPATH='".:/usr/local/lib/gforth/site-forth:/usr/local/share/gforth/site-forth:/usr/local/lib/gforth/0.7.0:/usr/local/share/gforth/0.7.0"'
 -fexceptions -fno-gcse -fno-strict-aliasing -fno-crossjumping
-fno-reorder-blocks -falign-labels=1 -falign-loops=1 -falign-jumps=1
-fno-defer-pop -fcaller-saves -fno-inline -o engine-fast-ll-reg.o -c ./engine.c
#

# ls -lrtA | tail -1
-rwxr-xr-x 1 root  root  126938 Jan 31 12:20 gforth-fast-ll
#
See that "-O0" gives no screen output and no compiled file output.


# gcc -ffloat-store -msse3 -mssse3 -m3dnow -msse4.1 -mfpmath=sse,387 
-I./../arch/386 -I. -Wall -O1 -fomit-frame-pointer -fforce-addr -DHAVE_CONFIG_H
-DFORCE_LL -DFORCE_REG
-DDEFAULTPATH='".:/usr/local/lib/gforth/site-forth:/usr/local/share/gforth/site-forth:/usr/local/lib/gforth/0.7.0:/usr/local/share/gforth/0.7.0"'
 -fexceptions -fno-gcse -fno-strict-aliasing -fno-crossjumping
-fno-reorder-blocks -falign-labels=1 -falign-loops=1 -falign-jumps=1
-fno-defer-pop -fcaller-saves -fno-inline -o engine-fast-ll-reg.o -c ./engine.c
./engine.c: In function 'gforth_engine':
./engine.c:460: error: unable to find a register to spill in class 'DIREG'
./engine.c:460: error: this is the insn:
(insn 5800 13080 5801 850 prim:1699 (parallel [
            (set (reg:SI 2 cx [2364])
                (unspec:SI [
                        (mem:BLK (reg/f:SI 1 dx [orig:2366 D.8048 ] [2366]) [0
A8])
                        (reg:QI 0 ax [2368])
                        (const_int 1 [0x1])
                        (reg:SI 2 cx [2367])
                    ] 30))
            (clobber (reg/f:SI 1 dx [orig:2366 D.8048 ] [2366]))
            (clobber (reg:CC 17 flags))
        ]) 864 {*strlenqi_1} (expr_list:REG_DEAD (reg:QI 0 ax [2368])
        (expr_list:REG_DEAD (reg:SI 2 cx [2367])
            (expr_list:REG_DEAD (reg/f:SI 1 dx [orig:2366 D.8048 ] [2366])
                (expr_list:REG_UNUSED (reg/f:SI 1 dx [orig:2366 D.8048 ]
[2366])
                    (expr_list:REG_UNUSED (reg:CC 17 flags)
                        (nil)))))))
./engine.c:460: confused by earlier errors, bailing out
#

# gcc -ffloat-store -msse3 -mssse3 -m3dnow -msse4.1 -mfpmath=sse,387 
-I./../arch/386 -I. -Wall -O3 -fomit-frame-pointer -fforce-addr -DHAVE_CONFIG_H
-DFORCE_LL -DFORCE_REG
-DDEFAULTPATH='".:/usr/local/lib/gforth/site-forth:/usr/local/share/gforth/site-forth:/usr/local/lib/gforth/0.7.0:/usr/local/share/gforth/0.7.0"'
 -fexceptions -fno-gcse -fno-strict-aliasing -fno-crossjumping
-fno-reorder-blocks -falign-labels=1 -falign-loops=1 -falign-jumps=1
-fno-defer-pop -fcaller-saves -fno-inline -o engine-fast-ll-reg.o -c ./engine.c
./engine.c: In function 'gforth_engine':
./engine.c:460: error: unable to find a register to spill in class
'GENERAL_REGS'
./engine.c:460: error: this is the insn:
(insn:HI 2564 2563 2565 367 prim-fast.i:4090 (set (reg:DI 2196)
        (mem/s/j/c:DI (plus:SI (reg/f:SI 20 frame)
                (const_int -180 [0xffffffffffffff4c])) [0 _d.d+0 S8 A32])) 88
{*movdi_2} (nil))
./engine.c:460: confused by earlier errors, bailing out
#

# gcc -ffloat-store -msse3 -mssse3 -m3dnow -msse4.1 -mfpmath=sse,387 
-I./../arch/386 -I. -Wall -Os -fomit-frame-pointer -fforce-addr -DHAVE_CONFIG_H
-DFORCE_LL -DFORCE_REG
-DDEFAULTPATH='".:/usr/local/lib/gforth/site-forth:/usr/local/share/gforth/site-forth:/usr/local/lib/gforth/0.7.0:/usr/local/share/gforth/0.7.0"'
 -fexceptions -fno-gcse -fno-strict-aliasing -fno-crossjumping
-fno-reorder-blocks -falign-labels=1 -falign-loops=1 -falign-jumps=1
-fno-defer-pop -fcaller-saves -fno-inline -o engine-fast-ll-reg.o -c ./engine.c
./engine.c: In function 'gforth_engine':
./engine.c:460: error: unable to find a register to spill in class 'DIREG'
./engine.c:460: error: this is the insn:
(insn:HI 1623 1621 1624 230 prim:662 (parallel [
            (set (reg:SI 2 cx [orig:2148 u ] [2148])
                (const_int 0 [0x0]))
            (set (reg/f:SI 0 ax [orig:2146 c_addr ] [2146])
                (plus:SI (reg/v/f:SI 1943 [ c_addr ])
                    (reg/v:SI 2 cx [orig:1942 u ] [1942])))
            (set (mem:BLK (reg/v/f:SI 1943 [ c_addr ]) [0 A8])
                (const_int 0 [0x0]))
            (use (subreg:QI (reg:SI 1 dx [orig:1278 spTOS.757 ] [1278]) 0))
            (use (reg/v:SI 2 cx [orig:1942 u ] [1942]))
        ]) 858 {*rep_stosqi} (expr_list:REG_DEAD (reg/v/f:SI 1943 [ c_addr ])
        (expr_list:REG_DEAD (reg/v:SI 2 cx [orig:1942 u ] [1942])
            (expr_list:REG_DEAD (reg:SI 1 dx [orig:1278 spTOS.757 ] [1278])
                (expr_list:REG_UNUSED (reg:SI 2 cx [orig:2148 u ] [2148])
                    (expr_list:REG_UNUSED (reg/f:SI 0 ax [orig:2146 c_addr ]
[2146])
                        (nil)))))))
./engine.c:460: confused by earlier errors, bailing out
# 


If I compile "-O1" and remove the "-fomit-frame-pointer" option then the
output (error message) is the same as: "-O1 -fomit-frame-pointer".

If I compile "-Os" and remove the "-fomit-frame-pointer" option then the
output (error message) is the same as: "-Os -fomit-frame-pointer".

If I compile "-O0", "-O2" or "-O3" and remove the "-fomit-frame-pointer" 
option then the output (error message) is the same as if I had used:
"-O2 -fomit-frame-pointer".

Even stripping the gcc command to the bare minimum can not skirt
the lack of enough registers to compile this code:

# gcc -I./../arch/386 -I. -Wall  -DHAVE_CONFIG_H -DFORCE_LL -DFORCE_REG
-DDEFAULTPATH='".:/usr/local/lib/gforth/site-forth:/usr/local/share/gforth/site-forth:/usr/local/lib/gforth/0.7.0:/usr/local/share/gforth/0.7.0"'
 -o engine-fast-ll-reg.o -c ./engine.c
./engine.c: In function 'gforth_engine':
./engine.c:460: error: unable to find a register to spill in class
'GENERAL_REGS'
./engine.c:460: error: this is the insn:
(insn 3333 3332 3334 360 prim-fast.i:3818 (set (reg:DI 4692)
        (mem/s/j/c:DI (plus:SI (reg/f:SI 20 frame)
                (const_int -4844 [0xffffffffffffed14])) [0 _d.d+0 S8 A32])) 88
{*movdi_2} (nil))
./engine.c:460: confused by earlier errors, bailing out

Thanks,
Rob


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35135
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