Revert "x86: Rewrite ix86_find_max_used_stack_alignment"

Revert

commit e754b70fe5470b975d31887fa5647f1c92d6522d
Author:     H.J. Lu <hjl.tools@gmail.com>
AuthorDate: Tue Apr 7 23:16:38 2026 +0800
Commit:     H.J. Lu <hjl.tools@gmail.com>
CommitDate: Mon Jul 6 16:11:45 2026 +0800

    x86: Rewrite ix86_find_max_used_stack_alignment

to fix PR target/126202.

gcc/

	PR target/126202
	* alias.cc (static_reg_base_value): Revert commit e754b70fe54.
	(find_base_term): Likewise.
	* alias.h (find_base_term): Likewise.
	* function.cc (thread_prologue_and_epilogue_insns): Likewise.
	* rtl.h (static_reg_base_value): Likewise.
	* config/i386/i386.cc (stack_access_data): Likewise.
	(ix86_find_all_reg_uses_1): Likewise.
	(ix86_find_all_reg_uses): Likewise.
	(ix86_access_stack_p): Likewise.
	(ix86_need_alignment_p_2): Likewise.
	(ix86_need_alignment_p_1): Likewise.
	(ix86_need_alignment_p): Likewise.
	(ix86_update_stack_alignment): Likewise.
	(ix86_find_max_used_stack_alignment): Likewise.
	(ix86_update_stack_alignment_2): Removed.
	(ix86_update_stack_alignment_1): Likewise.

gcc/testsuite/

	PR target/126202
	* g++.target/i386/pr126202-1.C: New test.
	* gcc.target/i386/pr126202-1.c: Likewise.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>