[Bug c/83789] New: __builtin_altivec_lvx fails for powerpc for altivec-4.c

[kaushik.phatak at kpitcummins dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83789

            Bug ID: 83789
           Summary: __builtin_altivec_lvx fails for powerpc for
                    altivec-4.c
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: kaushik.phatak at kpitcummins dot com
  Target Milestone: ---

Regression testcase gcc.target/powerpc/altivec-4.c fails for powerpc gcc-7
onwards.

$powerpc-linux-gcc -m32 -mhard-float -maltivec altivec-4.c -c
min.c: In function 'b':
min.c:16:7: internal compiler error: Segmentation fault
   i = __builtin_altivec_lvx (int1, pi);
       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
0x85d8690 crash_signal
       
/home/kaushikp/toolchain/powerpc/linux_build_71/../src/gcc-7.1.0/gcc/toplev.c:337
0x832f525 store_expr_with_bounds(tree_node*, rtx_def*, int, bool, bool,
tree_node*)
       
/home/kaushikp/toolchain/powerpc/linux_build_71/../src/gcc-7.1.0/gcc/expr.c:5575
0x8330c91 expand_assignment(tree_node*, tree_node*, bool)
       
/home/kaushikp/toolchain/powerpc/linux_build_71/../src/gcc-7.1.0/gcc/expr.c:5321
0x823bb98 expand_call_stmt
       
/home/kaushikp/toolchain/powerpc/linux_build_71/../src/gcc-7.1.0/gcc/cfgexpand.c:2656
0x823bb98 expand_gimple_stmt_1
       
/home/kaushikp/toolchain/powerpc/linux_build_71/../src/gcc-7.1.0/gcc/cfgexpand.c:3571
0x823bb98 expand_gimple_stmt
       
/home/kaushikp/toolchain/powerpc/linux_build_71/../src/gcc-7.1.0/gcc/cfgexpand.c:3737
0x823cbd0 expand_gimple_basic_block
       
/home/kaushikp/toolchain/powerpc/linux_build_71/../src/gcc-7.1.0/gcc/cfgexpand.c:5744
0x8241e36 execute
       
/home/kaushikp/toolchain/powerpc/linux_build_71/../src/gcc-7.1.0/gcc/cfgexpand.c:6357
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The builtin generates the 'CODE_FOR_altivec_lvx_v4si_2op' instruction which 
returns CODE_FOR_nothing resulting in Segmentation fault.
The pattern 'CODE_FOR_altivec_lvx_v4si_2op' was introduced by the following
patch I believe,
https://gcc.gnu.org/ml/gcc-patches/2016-04/msg01110.html

The pattern tests for TARGET_64BIT and the testcase passes for powerpc64,
however fails for 32-bit targets. This passed in GCC-6 and earlier branches.

Should we modify the testcase so it runs only for 64-bit targets, 
or should this builtin work for 32-bit targets as well?