Revision 161654 compiles the attached test-case correctly at -O2.
Revision 161655 does not (except at -O0).
I guess the bug is apparent for other targets too, but I haven't checked.
Note for cris-elf this bb, correctly compiled (path for *s = '0' to sf return):
.L7:
move.b 48,$r13
move.b $r13,[$r11]
addq 1,$r13
ret
move.b $r13,[$r9]
and incorrectly:
.L7:
move.b 48,$r9
move.b $r9,[$r10-1]
addq 10,$r9
move.b $r9,[$r10-1]
ret
nop
(storing '0' and then adding 10 to it, making ':')
The test-case is distilled from newlib/libc/stdlib/dtoa.c, where the bug causes
a store of ':' directly, without bothering to first store '0' :) but apparently
the same bug.
The miscompilation is exposed as regressions in three fortran test-cases from
r161655 and on, up to and including at least r161893:
Running /tmp/regress-0630-55/gcc/gcc/testsuite/gfortran.dg/dg.exp ...
... (non-regressions elided)
FAIL: gfortran.dg/edit_real_1.f90 -O0 execution test
FAIL: gfortran.dg/edit_real_1.f90 -O1 execution test
FAIL: gfortran.dg/edit_real_1.f90 -O2 execution test
FAIL: gfortran.dg/edit_real_1.f90 -O3 -fomit-frame-pointer execution test
FAIL: gfortran.dg/edit_real_1.f90 -O3 -fomit-frame-pointer -funroll-loops
execution test
FAIL: gfortran.dg/edit_real_1.f90 -O3 -fomit-frame-pointer -funroll-all-loops
-finline-functions execution test
FAIL: gfortran.dg/edit_real_1.f90 -O3 -g execution test
FAIL: gfortran.dg/edit_real_1.f90 -Os execution test
FAIL: gfortran.dg/fmt_float.f90 -O0 output pattern test, is
0.10E+01 0.10E+00 0.:0E\
(...verbosity elided but note the ":"; there's a "1" expected there)
FAIL: gfortran.dg/fmt_float.f90 -O1 output pattern test, is
0.10E+01 0.10E+00 0.:0E\
(...further similar fmt_float results elided)
FAIL: gfortran.dg/fmt_zero_precision.f90 -O0 output pattern test, is 1.<
(...verbosity elided)
FAIL: gfortran.dg/fmt_zero_precision.f90 -O1 output pattern test, is 1.<
(...further similar fmt_zero_precision results elided)
--
Summary: [4.6 Regression]: miscompilation of newlib dtoa.c after
mem-ref2 merge
Product: gcc
Version: 4.6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: hp at gcc dot gnu dot org
GCC host triplet: x86_64-linux
GCC target triplet: cris-elf
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44852
