[Bug middle-end/78433] [7 Regression] glibc posix/execvpe.c gets miscompiled with -O3

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78433

--- Comment #4 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
On X86_64:

--- good        2016-11-20 19:12:27.353412333 +0100
+++ bad 2016-11-20 19:13:37.738531151 +0100
@@ -892,7 +892,7 @@
        leaq    1(%rax), %rdx
        cmpq    $0, -8(%r12,%rdx,8)
        jne     .L115
-       leaq    38(,%rax,8), %rax
+       leaq    31(,%rax,8), %rax
        movq    %rsp, %r14
        andq    $-16, %rax
        subq    %rax, %rsp
@@ -1009,7 +1009,7 @@
        leaq    1(%rdx), %rax
        cmpq    $0, -8(%r12,%rax,8)
        jne     .L132
-       leaq    38(,%rdx,8), %rdx
+       leaq    31(,%rdx,8), %rdx
        movq    %rsp, -112(%rbp)
        movq    -56(%rbp), %rcx
        andq    $-16, %rdx