[Bug target/50603] New: [x32] Unnecessary lea

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50603

             Bug #: 50603
           Summary: [x32] Unnecessary lea
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: hjl.to...@gmail.com
                CC: ubiz...@gmail.com


[hjl@gnu-6 ilp32-2]$ cat int.c
extern int *foo;

int bar (int x) { return foo[x]; }
[hjl@gnu-6 ilp32-2]$ make int.s
/export/build/gnu/gcc-x32/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/gcc-x32/build-x86_64-linux/gcc/ -S -mx32  -O2 int.c
[hjl@gnu-6 ilp32-2]$ cat int.s
    .file    "int.c"
    .text
    .p2align 4,,15
    .globl    bar
    .type    bar, @function
bar:
.LFB0:
    .cfi_startproc
    movl    foo(%rip), %eax
    leal    (%rax,%rdi,4), %edi
    movl    (%edi), %eax
    ret
    .cfi_endproc
.LFE0:
    .size    bar, .-bar
    .ident    "GCC: (GNU) 4.7.0 20110923 (experimental)"
    .section    .note.GNU-stack,"",@progbits
[hjl@gnu-6 ilp32-2]$ 

We can generate

    movl    foo(%rip), %eax
    movl    (%eax,%edi,4), %eax
        ret