[Bug rtl-optimization/78735] New: profiledbootstrap with --enable-checking=yes,rtl fails on trunk due to -Werror=strict-overflow

["sirl at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78735

            Bug ID: 78735
           Summary: profiledbootstrap with --enable-checking=yes,rtl fails
                    on trunk due to -Werror=strict-overflow
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: sirl at gcc dot gnu.org
  Target Milestone: ---

Hi,

current trunk (tried r243299 and r243376) on x86_64 fails a profiledbootstrap
with --enable-checking=yes,rtl like that:

/home/fsirl/rpmbuild/BUILD/gcc-7.0.0-r243376/obj-x86_64-suse-linux/./prev-gcc/xg++
-B/home/fsirl/rpmbuild/BUILD/gcc-7.0.0-r243376/obj-x86_64-suse-linux/./prev-gcc/
-B/usr/x86_64-suse-linux/bin/ -nostdinc++
-B/home/fsirl/rpmbuild/BUILD/gcc-7.0.0-r243376/obj-x86_64-suse-linux/prev-x86_64-suse-linux/libstdc++-v3/src/.libs
-B/home/fsirl/rpmbuild/BUILD/gcc-7.0.0-r243376/obj-x86_64-suse-linux/prev-x86_64-suse-linux/libstdc++-v3/libsupc++/.libs

-I/home/fsirl/rpmbuild/BUILD/gcc-7.0.0-r243376/obj-x86_64-suse-linux/prev-x86_64-suse-linux/libstdc++-v3/include/x86_64-suse-linux

-I/home/fsirl/rpmbuild/BUILD/gcc-7.0.0-r243376/obj-x86_64-suse-linux/prev-x86_64-suse-linux/libstdc++-v3/include
 -I/home/fsirl/rpmbuild/BUILD/gcc-7.0.0-r243376/libstdc++-v3/libsupc++
-L/home/fsirl/rpmbuild/BUILD/gcc-7.0.0-r243376/obj-x86_64-suse-linux/prev-x86_64-suse-linux/libstdc++-v3/src/.libs
-L/home/fsirl/rpmbuild/BUILD/gcc-7.0.0-r243376/obj-x86_64-suse-linux/prev-x86_64-suse-linux/libstdc++-v3/libsupc++/.libs
-fno-PIE -c   -O2 -g -fmessage-length=0 -D_FORTIFY_SOURCE=2 -funwind-tables
-fasynchronous-unwind-tables -U_FORTIFY_SOURCE -fprofile-use -DIN_GCC    
-fno-exceptions -fno-rtti -fasynchronous-unwind-tables -W -Wall -Wno-narrowing
-Wwrite-strings -Wcast-qual -Wmissing-format-attribute -Woverloaded-virtual
-pedantic -Wno-long-long -Wno-variadic-macros -Wno-overlength-strings -Werror
-fno-common  -DHAVE_CONFIG_H -I. -I. -I../../gcc -I../../gcc/.
-I../../gcc/../include -I../../gcc/../libcpp/include 
-I../../gcc/../libdecnumber -I../../gcc/../libdecnumber/bid -I../libdecnumber
-I../../gcc/../libbacktrace   -o combine.o -MT combine.o -MMD -MP -MF
./.deps/combine.TPo ../../gcc/combine.c
In file included from ../../gcc/combine.c:83:0:
../../gcc/combine.c: In function 'int recog_for_combine(rtx_def**, rtx_insn*,
rtx_def**)':
../../gcc/rtl.h:1076:17: error: assuming signed overflow does not occur when
assuming that (X - c) > X is always false [-Werror=strict-overflow]
      if (_i < 0 || _i >= GET_NUM_ELEM (_rtvec))    \
                 ^
../../gcc/rtl.h:702:45: note: in definition of macro 'GET_CODE'
 #define GET_CODE(RTX)     ((enum rtx_code) (RTX)->code)
                                             ^~~
../../gcc/rtl.h:1298:28: note: in expansion of macro 'RTVEC_ELT'
 #define XVECEXP(RTX, N, M) RTVEC_ELT (XVEC (RTX, N), M)
                            ^~~~~~~~~
../../gcc/combine.c:11088:21: note: in expansion of macro 'XVECEXP'
       if (GET_CODE (XVECEXP (pat, 0, i)) == CLOBBER
                     ^~~~~~~
../../gcc/rtl.h:1076:17: error: assuming signed overflow does not occur when
assuming that (X - c) > X is always false [-Werror=strict-overflow]
      if (_i < 0 || _i >= GET_NUM_ELEM (_rtvec))    \
                 ^
../../gcc/rtl.h:702:45: note: in definition of macro 'GET_CODE'
 #define GET_CODE(RTX)     ((enum rtx_code) (RTX)->code)
                                             ^~~
../../gcc/rtl.h:1298:28: note: in expansion of macro 'RTVEC_ELT'
 #define XVECEXP(RTX, N, M) RTVEC_ELT (XVEC (RTX, N), M)
                            ^~~~~~~~~
../../gcc/combine.c:11088:21: note: in expansion of macro 'XVECEXP'
       if (GET_CODE (XVECEXP (pat, 0, i)) == CLOBBER
                     ^~~~~~~
../../gcc/rtl.h:1076:17: error: assuming signed overflow does not occur when
assuming that (X - c) > X is always false [-Werror=strict-overflow]
      if (_i < 0 || _i >= GET_NUM_ELEM (_rtvec))    \
                 ^
../../gcc/rtl.h:702:45: note: in definition of macro 'GET_CODE'
 #define GET_CODE(RTX)     ((enum rtx_code) (RTX)->code)
                                             ^~~
../../gcc/rtl.h:1298:28: note: in expansion of macro 'RTVEC_ELT'
 #define XVECEXP(RTX, N, M) RTVEC_ELT (XVEC (RTX, N), M)
                            ^~~~~~~~~
../../gcc/combine.c:11088:21: note: in expansion of macro 'XVECEXP'
       if (GET_CODE (XVECEXP (pat, 0, i)) == CLOBBER
                     ^~~~~~~
More of the same errors follow. A simple "make bootstrap" works fine.

The build (actually the SRCRPM from OBS with updated sources) was configured
like that:

CFLAGS='-O2 -g -fmessage-length=0 -D_FORTIFY_SOURCE=2 -funwind-tables
-fasynchronous-unwind-tables -U_FORTIFY_SOURCE'
CXXFLAGS='-O2 -g -fmessage-length=0 -D_FORTIFY_SOURCE=2 -funwind-tables
-fasynchronous-unwind-tables -U_FORTIFY_SOURCE'
XCFLAGS='-O2 -g -fmessage-length=0 -D_FORTIFY_SOURCE=2 -funwind-tables
-fasynchronous-unwind-tables -U_FORTIFY_SOURCE'
TCFLAGS='-O2 -g -fmessage-length=0 -D_FORTIFY_SOURCE=2 -funwind-tables
-fasynchronous-unwind-tables -U_FORTIFY_SOURCE'
../configure CC=gcc-6 CXX=g++-6 --prefix=/usr --infodir=/usr/share/info
--mandir=/usr/share/man --libdir=/usr/lib64 --libexecdir=/usr/lib64
--enable-languages=c,c++,objc,fortran,obj-c++,go --enable-checking=yes,rtl
--with-gxx-include-dir=/usr/include/c++/7 --enable-ssp --disable-libssp
--disable-libvtv --disable-libcc1 --disable-plugin
--with-bugurl=http://bugs.opensuse.org/ '--with-pkgversion=SUSE Linux'
--with-slibdir=/lib64 --with-system-zlib --enable-__cxa_atexit
--enable-libstdcxx-allocator=new --disable-libstdcxx-pch
--with-default-libstdcxx-abi=gcc4-compatible
--enable-version-specific-runtime-libs --enable-linker-build-id
--enable-linux-futex --enable-gnu-indirect-function --program-suffix=-7
--without-system-libunwind --enable-multilib --with-arch-32=x86-64
--with-tune=generic --build=x86_64-suse-linux --host=x86_64-suse-linux

make profiledbootstrap STAGE1_CFLAGS=-g 'BOOT_CFLAGS=-O2 -g -fmessage-length=0
-D_FORTIFY_SOURCE=2 -funwind-tables -fasynchronous-unwind-tables
-U_FORTIFY_SOURCE'