RISC-V: Normalize user vsetvl intrinsics[PR112092]

RISC-V: Normalize user vsetvl intrinsics[PR112092]

Since our user vsetvl intrinsics are defined as just calculate the VL output
which is the number of the elements to be processed. Such intrinsics do not
have any side effects.  We should normalize them when they have same ratio.

E.g __riscv_vsetvl_e8mf8 result is same as __riscv_vsetvl_e64m1.

Normalize them can allow us have better codegen.
Consider this following example:

#include "riscv_vector.h"

void foo(int32_t *in1, int32_t *in2, int32_t *in3, int32_t *out, size_t n, int cond, int avl) {

  size_t vl;
  if (cond)
    vl = __riscv_vsetvl_e32m1(avl);
  else
    vl = __riscv_vsetvl_e16mf2(avl);
  for (size_t i = 0; i < n; i += 1) {
    vint32m1_t a = __riscv_vle32_v_i32m1(in1, vl);
    vint32m1_t b = __riscv_vle32_v_i32m1_tu(a, in2, vl);
    vint32m1_t c = __riscv_vle32_v_i32m1_tu(b, in3, vl);
    __riscv_vse32_v_i32m1(out, c, vl);
  }
}

Before this patch:

foo:
        beq     a5,zero,.L2
        vsetvli a6,a6,e32,m1,tu,ma
.L3:
        li      a5,0
        beq     a4,zero,.L9
.L4:
        vle32.v v1,0(a0)
        addi    a5,a5,1
        vle32.v v1,0(a1)
        vle32.v v1,0(a2)
        vse32.v v1,0(a3)
        bne     a4,a5,.L4
.L9:
        ret
.L2:
        vsetvli zero,a6,e32,m1,tu,ma
        j       .L3

After this patch:

foo:
	li	a5,0
	vsetvli	zero,a6,e32,m1,tu,ma
	beq	a4,zero,.L9
.L4:
	vle32.v	v1,0(a0)
	addi	a5,a5,1
	vle32.v	v1,0(a1)
	vle32.v	v1,0(a2)
	vse32.v	v1,0(a3)
	bne	a4,a5,.L4
.L9:
	ret

	PR target/112092

gcc/ChangeLog:

	* config/riscv/riscv-vector-builtins-bases.cc: Normalize the vsetvls.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/vsetvl/pr109743-1.c: Adapt test.
	* gcc.target/riscv/rvv/vsetvl/pr109743-3.c: Ditto.
	* gcc.target/riscv/rvv/vsetvl/vsetvl-11.c: Ditto.
	* gcc.target/riscv/rvv/vsetvl/vsetvl-15.c: Ditto.
	* gcc.target/riscv/rvv/vsetvl/vsetvl-22.c: Ditto.
	* gcc.target/riscv/rvv/vsetvl/vsetvlmax-13.c: Ditto.
	* gcc.target/riscv/rvv/vsetvl/vsetvlmax-15.c: Ditto.
	* gcc.target/riscv/rvv/vsetvl/vsetvlmax-5.c: Ditto.
	* gcc.target/riscv/rvv/vsetvl/vsetvlmax-7.c: Ditto.
	* gcc.target/riscv/rvv/vsetvl/vsetvlmax-8.c: Ditto.
	* gcc.target/riscv/rvv/vsetvl/pr112092-1.c: New test.
	* gcc.target/riscv/rvv/vsetvl/pr112092-2.c: New test.