These patches are for this bug:
"RFE: extend -falign-xyz syntax"

The test program:

int g();
int f(int i) {
        i *= 3;
        while (--i > 100) {
 L1:            if (g()) goto L1;
                if (g()) goto L2;
        return i;
 L2:    return 123;

"-O2" assembly before the patch:        After the patch:
        .text                                   .text
        .p2align 4,,15                          .p2align 4
        .globl  f                               .globl  f
        .type   f, @function                    .type   f, @function
f:                                      f:
.LFB0:                                  .LFB0:
        pushq   %rbx                            pushq   %rbx
        leal    (%rdi,%rdi,2), %ebx             leal    (%rdi,%rdi,2), %ebx
        .p2align 4,,10                          .p2align 4,,10
        .p2align 3                              .p2align 3
.L2:                                    .L2:
        subl    $1, %ebx                        subl    $1, %ebx
        cmpl    $100, %ebx                      cmpl    $100, %ebx
        jle     .L1                             jle     .L1
        .p2align 4,,10                          .p2align 4,,10
        .p2align 3                              .p2align 3
.L3:                                    .L3:
        xorl    %eax, %eax                      xorl    %eax, %eax
        call    g                               call    g
        testl   %eax, %eax                      testl   %eax, %eax
        jne     .L3                             jne     .L3
        call    g                               call    g
        testl   %eax, %eax                      testl   %eax, %eax
        je      .L2                             je      .L2
        movl    $123, %ebx                      movl    $123, %ebx
.L4:                                    .L4:
.L1:                                    .L1:
        movl    %ebx, %eax                      movl    %ebx, %eax
        popq    %rbx                            popq    %rbx
        ret                                     ret

This is version 6 of the patch set.

Bernd asked to replace use of a new SUBALIGN_LOG define with a hook.
Don't see an easy way to do that (short of adding a dedicated hook),
for now retained SUBALIGN_LOG method. Suggestions welcome.

Changes since version 5:

* Changes in rs6000, mips, alpha, visium, sh, rx, spu to accomodate
  new alignment options.
* Explicitly list secondary alignment of 8 ("n,m,8") in x86 tables
  for all types of jump targets.

Changes since version 4:

* Deleted rather than NOPed -malign-foo=N support.
* Improved behavior match with x86 8-byte subalignment for labels.

Changes since version 3:

* Improved documentation in invoke.texi
* Fixed x86-specific calculation of default N2 value:
  previous version was doing it incorrectly for cross-compile

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