PATCH - Fix an ICE compiling for ppc64

[Fariborz Jahanian <fjahanian at apple dot com>]

Attached patch fixes an ICE compiling the test case with: -m64 -O1 
-static. -m64 is Apple's ppc64 ABI option. Problem arises after 
'combine' phase combines a series of true-dependent rtl insns into a 
single compare insn involving an integer constant. However, constant in 
this pattern does not meet the constraint laid down in rs6000.md 
pattern for integer constants. Reload then attempts to move this 
constant into a register via memory. Generated pattern to do the 'move' 
causes an invalid insn. Patch fixes this problem by introducing a new 
'predicate' which enforces what the constraints enforce. This prevents 
'combine' to combine into a pattern which is unsuitable and requires a 
memory load in 'reload'. Patch has been tested with Dejagnu test suite 
and -m64.

OK for mainline?

- fariborz

1) Pattern that 'combine' puts out:

(insn 41 40 42 1 (parallel [
            (set (reg:CC 68 cr0 [141])
                (compare:CC (eq:DI (reg:DI 0 r0 [133])
                        (const_int 549755813921 [0x8000000021]))
                    (const_int 0 [0x0])))
            (set (reg/v:DI 10 r10 [orig:120 negate_range ] [120])
                (eq:DI (reg:DI 0 r0 [133])
                    (const_int 549755813921 [0x8000000021])))
            (clobber (scratch:DI))
        ]) 396 {*rs6000.md:11887} (insn_list:REG_DEP_TRUE 32 (nil))
    (expr_list:REG_UNUSED (scratch:DI)
        (expr_list:REG_UNUSED (scratch:DI)
            (expr_list:REG_DEAD (reg:DI 0 r0 [133])
                (nil)))))

2) Behavior without this patch:

% gcc -c -m64 -O1 -static bad.c
bad.c: In function 'match':
bad.c:28: error: unrecognizable insn:
(insn 136 135 41 1 (set (reg:DI 2 r2)
        (mem/u/i:DI (symbol_ref/u:DI ("*LC1") [flags 0x2]) [0 S8 A64])) 
-1 (nil)
    (nil))
bad.c:28: internal compiler error: in extract_insn, at recog.c:2033
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://developer.apple.com/bugreporter> for instructions.

ChangeLog:

2005-06-03  Fariborz Jahanian <fjahanian@apple.com>
        * rs6000/predicates.md (reg_or_cshort_operand): New.
        * rs6000/rs6000.md : Use reg_or_cshort_operand for ppc64 
compares.

Attachment: fsf-patch-3869444.txt
Description: Text document