http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57032
--- Comment #1 from Uros Bizjak <ubizjak at gmail dot com> 2013-04-22 15:20:38
UTC ---
For some reason, LRA does not fix-up (insn 12):
(insn 12 11 13 2 (set (reg/v:DI 72 [ hi ])
(unsigned_fix:DI (reg:DF 83 [ D.5360 ])))
../../../gcc-svn/trunk/libgcc/libgcc2.c:1334 138 {*fix_truncdfdi2}
(expr_list:REG_DEAD (reg:DF 83 [ D.5360 ])
(nil)))
with a spill to memory via *movdi combo (as is the case with reload):
cvttq/c $f10,$f10 # 12 *fix_truncdfdi2 [length = 4]
stt $f10,0($30) # 60 *movdi/12 [length = 4]
ldq $1,0($30) # 61 *movdi/8 [length = 4]
But ignores the above alternative and goes with:
12: r108:DI=uns_fix(r83:DF)
REG_DEAD r83:DF
Inserting insn reload after:
58: r72:DI=r108:DI
Creating newreg=109, assigning class NO_REGS to secondary r109
58: r109:DI=r108:DI
Inserting the sec. move after:
59: r72:DI=r109:DI
Choosing alt 7 in insn 59: (0) r (1) m
Choosing alt 0 in insn 13: (2) rJ
Choosing alt 0 in insn 14: (0) =f (1) f
Creating newreg=110 from oldreg=72, assigning class FLOAT_REGS to r110
14: r87:DF=float(r110:DI)
Inserting insn reload before:
60: r110:DI=r72:DI
Creating newreg=111, assigning class NO_REGS to secondary r111
60: r111:DI=r72:DI
Inserting the sec. move after:
61: r110:DI=r111:DI
Choosing alt 9 in insn 61: (0) *f (1) *fJ
Creating newreg=112 from oldreg=111, assigning class FLOAT_REGS to r112
61: r110:DI=r112:DI
Inserting insn reload before:
62: r112:DI=r111:DI
Choosing alt 9 in insn 62: (0) *f (1) *fJ
Creating newreg=113 from oldreg=111, assigning class FLOAT_REGS to r113
62: r112:DI=r113:DI
Inserting insn reload before:
63: r113:DI=r111:DI
...
This creates a reload loop.
