Arm64: Better addressing mode for float/double array access

[kunalspathak]

In #61293, we optimized the array access with better addressing mode, but we still need to improve it for float/double array types.

private static double[] Crb;

public double issue4(int n)
{
 double result = 0;
 for (int i = 0; i < n; i++)
 {
 result += Crb[i];
 }
 return result;
}

G_M38607_IG03:
 mov x1, x0
 ldr w2, [x1,#8]
 cmp w20, w2
 bhs G_M38607_IG06
 ubfiz x2, x20, #3, #32
 add x2, x2, #16
 ldr d16, [x1, x2]
 fadd d8, d16, d8
 add w20, w20, #1
 cmp w20, w19
 blt G_M38607_IG03

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Issue Details

---

In #61293, we optimized the array access with better addressing mode, but we still need to improve it for float/double array types.

private static double[] Crb;

public double issue4(int n)
{
 double result = 0;
 for (int i = 0; i < n; i++)
 {
 result += Crb[i];
 }
 return result;
}

G_M38607_IG03:
 mov x1, x0
 ldr w2, [x1,#8]
 cmp w20, w2
 bhs G_M38607_IG06
 ubfiz x2, x20, #3, #32
 add x2, x2, #16
 ldr d16, [x1, x2]
 fadd d8, d16, d8
 add w20, w20, #1
 cmp w20, w19
 blt G_M38607_IG03

Author:	kunalspathak
Assignees:	-
Labels:	area-CodeGen-coreclr, untriaged
Milestone:	-

[kunalspathak]

@dotnet/jit-contrib