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Date: Tue, 10 Feb 2009 20:19:00 -0000
Subject: [Bug target/39148]  New: -Os increase code size when stack is aligned
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[hjl@gnu-6 pr39137]$ cat pr39137-3.i
void foo (unsigned long long *);

void
bar (void)
{
  unsigned long long l __attribute__ ((aligned(32)));
  foo (&l);
}
[hjl@gnu-6 pr39137]$ /export/build/gnu/gcc-work/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/gcc-avx/build-x86_64-linux/gcc/ -m32 -Os  pr39137-3.i -S
[hjl@gnu-6 pr39137]$ cat pr39137-3.s
        .file   "pr39137-3.i"
        .text
.globl bar
        .type   bar, @function
bar:
        leal    4(%esp), %ecx
        andl    $-32, %esp
        pushl   -4(%ecx)
        pushl   %ebp
        movl    %esp, %ebp
        pushl   %ecx
        subl    $64, %esp
        leal    -56(%ebp), %eax
        pushl   %eax
        call    foo
        movl    -4(%ebp), %ecx
        addl    $16, %esp
        leave
        leal    -4(%ecx), %esp
        ret
        .size   bar, .-bar
[hjl@gnu-6 pr39137]$ /export/build/gnu/gcc-work/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/gcc-avx/build-x86_64-linux/gcc/ -m32 -O  pr39137-3.i -S
[hjl@gnu-6 pr39137]$ cat pr39137-3.s
        .file   "pr39137-3.i"
        .text
.globl bar
        .type   bar, @function
bar:
        pushl   %ebp
        movl    %esp, %ebp
        andl    $-32, %esp
        subl    $48, %esp
        leal    16(%esp), %eax
        movl    %eax, (%esp)
        call    foo
        leave
        ret
        .size   bar, .-bar
[hjl@gnu-6 pr39137]$ 

-Os generates bigger binary.


-- 
           Summary: -Os increase code size when stack is aligned
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: hjl dot tools at gmail dot com
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39148