[Bug tree-optimization/57147] New: [4.9 Regression]: setjmp call and if body wrongly elided (function runs off early end)

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57147

             Bug #: 57147
           Summary: [4.9 Regression]: setjmp call and if body wrongly
                    elided (function runs off early end)
    Classification: Unclassified
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: roland@gnu.org
            Target: arm-linux-gnueabi


Created attachment 30006
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30006
preprocessed source

This is with trunk@198549.  It's a regression from gcc-4_8-branch@198420.

Preprocessed source attached.

Configured as: --target=arm-linux-gnueabi --with-arch=armv7-a
Command line below.

This example is not expected to be usable on an arm-linux-gnueabi system,
but the problem is easily seen by examining the assembly.  In the function
TestSyscall, a good compilation calls _setjmp, returns normally on a
nonzero result, and ends in an __assert_fail call (a noreturn function, so
no epilogue/return after the call) on a zero result.  In a bad compilation,
the function just ends where the _setjmp call should be, no epilogue, no
return (so execution just runs into the following function).


gcc/cc1 -v  -fpreprocessed syscall_return_regs_test.i -quiet -dumpbase
syscall_return_regs_test.c -mtls-dialect=gnu -auxbase-strip
scons-out/nacl_irt_test-arm-glibc/obj/tests/syscall_return_regs/syscall_return_regs_test.o
-g -O2 -Wstrict-prototypes -Wall -Wundef -Wpedantic -Werror
-Wno-variadic-macros -Wno-unused-local-typedefs -std=gnu99 -version
-fomit-frame-pointer -fdiagnostics-show-option -o syscall_return_regs_test.s
GNU C (GCC) version 4.9.0 20130502 (experimental) (arm-linux-gnueabi)
    compiled by GNU C version 4.6.3, GMP version 5.0.2, MPFR version 3.1.0-p3,
MPC version 0.9
GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
ignoring nonexistent directory
"/usr/local/google/home/mcgrathr/gnu/build/inst/lib/gcc/arm-linux-gnueabi/4.9.0/include"
ignoring nonexistent directory
"/usr/local/google/home/mcgrathr/gnu/build/inst/lib/gcc/arm-linux-gnueabi/4.9.0/include-fixed"
ignoring nonexistent directory
"/usr/local/google/home/mcgrathr/gnu/build/inst/arm-linux-gnueabi/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/google/home/mcgrathr/gnu/build/inst/arm-linux-gnueabi/sys-include
End of search list.
GNU C (GCC) version 4.9.0 20130502 (experimental) (arm-linux-gnueabi)
    compiled by GNU C version 4.6.3, GMP version 5.0.2, MPFR version 3.1.0-p3,
MPC version 0.9
GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
Compiler executable checksum: e560f858071b4c04ef52cbbad3e21d4b