i386: x r<< (c - y) to x r>> y etc. optimization [PR117930]

i386: x r<< (c - y) to x r>> y etc. optimization [PR117930]

The following patch optimizes x r<< (c - y) to x r>> y,
x r>> (c - y) to x r<< y, x r<< (c + y) to x r<< y and
x r>> (c + y) to x r>> y if c is a multiple of x's bitsize.

2024-12-07  Jakub Jelinek  <jakub@redhat.com>

	PR target/117930
	* config/i386/i386.md (crotate): New define_code_attr.
	(*<insn><mode>3_add, *<insn><mode>3_add_1,
	*<insn><mode>3_sub, *<insn><mode>3_sub_1): New define_insn_and_split
	patterns plus following define_split for constant first input
	operand.

	* gcc.target/i386/pr117930.c: New test.