https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109093
H.J. Lu <hjl.tools at gmail dot com> changed:
What |Removed |Added
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CC| |crazylht at gmail dot com
--- Comment #10 from H.J. Lu <hjl.tools at gmail dot com> ---
We have
static bool
ix86_can_eliminate (const int from, const int to)
{
if (stack_realign_fp)
return ((from == ARG_POINTER_REGNUM
&& to == HARD_FRAME_POINTER_REGNUM)
|| (from == FRAME_POINTER_REGNUM
&& to == STACK_POINTER_REGNUM));
else
return to == STACK_POINTER_REGNUM ? !frame_pointer_needed : true;
}
Before IRA, stack_realign_fp is set to true by AVX piecewise move and store.
LRA replaces frame pointer with stack pointer:
insn 259 261 297 4 (set (reg/f:DI 2 cx [144])
(plus:DI (reg/f:DI 7 sp)
(const_int -32 [0xffffffffffffffe0]))) 241 {*leadi}
(expr_list:REG_EQUAL (plus:DI (reg/f:DI 19 frame)
(const_int -32 [0xffffffffffffffe0]))
(nil)))
In ix86_finalize_stack_frame_flags, stack_realign_fp is set to false. Since
the stack realignment skipped, local variable is no longer properly aligned.
