[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

[schwab@linux-m68k.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #45 from Andreas Schwab <schwab@linux-m68k.org> ---
It also breaks a lot of tests on m68k, eg:

$ gcc/xgcc -B gcc/ ../gcc/testsuite/gcc.dg/pr17957.c 
../gcc/testsuite/gcc.dg/pr17957.c: In function ‘vadd’:
../gcc/testsuite/gcc.dg/pr17957.c:6:1: internal compiler error: in
expand_one_stack_var_1, at cfgexpand.c:1221
 vadd (void)
 ^
0x662055 expand_one_stack_var_1
        ../../gcc/cfgexpand.c:1221
0x670685 expand_one_ssa_partition
        ../../gcc/cfgexpand.c:1295
0x670685 expand_used_vars
        ../../gcc/cfgexpand.c:1940
0x671e20 execute
        ../../gcc/cfgexpand.c:6084