RFR: 8282204: Use lea instructions for arithmetic operations on x86_64 [v5]

[Jie Fu]

On Fri, 25 Feb 2022 23:19:09 GMT, Jie Fu <jiefu at openjdk.org> wrote:

> I tested the following code pattern with `clang -c -O{1, 2, 3} ...`.
> `lea` is generated for all the cases.

The generated `lea`:

const.o:	file format Mach-O 64-bit x86-64


Disassembly of section __TEXT,__text:

0000000000000000 __Z8testInt1ii:
       0: 55                           	pushq	%rbp
       1: 48 89 e5                     	movq	%rsp, %rbp
       4: 8d 44 b7 20                  	leal	32(%rdi,%rsi,4), %eax
       8: 5d                           	popq	%rbp
       9: c3                           	retq
       a: 66 0f 1f 44 00 00            	nopw	(%rax,%rax)

0000000000000010 __Z8testInt2ii:
      10: 55                           	pushq	%rbp
      11: 48 89 e5                     	movq	%rsp, %rbp
      14: 8d 04 b7                     	leal	(%rdi,%rsi,4), %eax
      17: 5d                           	popq	%rbp
      18: c3                           	retq
      19: 0f 1f 80 00 00 00 00         	nopl	(%rax)

0000000000000020 __Z8testInt3ii:
      20: 55                           	pushq	%rbp
      21: 48 89 e5                     	movq	%rsp, %rbp
      24: 8d 44 37 10                  	leal	16(%rdi,%rsi), %eax
      28: 5d                           	popq	%rbp
      29: c3                           	retq
      2a: 66 0f 1f 44 00 00            	nopw	(%rax,%rax)

0000000000000030 __Z9testLong1ll:
      30: 55                           	pushq	%rbp
      31: 48 89 e5                     	movq	%rsp, %rbp
      34: 48 8d 44 b7 20               	leaq	32(%rdi,%rsi,4), %rax
      39: 5d                           	popq	%rbp
      3a: c3                           	retq
      3b: 0f 1f 44 00 00               	nopl	(%rax,%rax)

0000000000000040 __Z9testLong2ll:
      40: 55                           	pushq	%rbp
      41: 48 89 e5                     	movq	%rsp, %rbp
      44: 48 8d 04 b7                  	leaq	(%rdi,%rsi,4), %rax
      48: 5d                           	popq	%rbp
      49: c3                           	retq
      4a: 66 0f 1f 44 00 00            	nopw	(%rax,%rax)

0000000000000050 __Z9testLong3ll:
      50: 55                           	pushq	%rbp
      51: 48 89 e5                     	movq	%rsp, %rbp
      54: 48 8d 44 37 10               	leaq	16(%rdi,%rsi), %rax
      59: 5d                           	popq	%rbp
      5a: c3                           	retq

-------------

PR: https://git.openjdk.java.net/jdk/pull/7560