===================================================================
@@ -0,0 +1,10 @@
+/* { dg-do compile { target { *-*-linux* && { ! ia32 } } } } */
+/* { dg-options "-O -mabi=ms -mstackrealign" } */
+
+typedef float V __attribute__ ((vector_size (16)));
+
+int fn1 (V * x)
+{
+ V a = *x;
+ return a[0];
+}
===================================================================
@@ -11271,11 +11271,14 @@ ix86_compute_frame_layout (struct ix86_frame *fram
frame->nregs = ix86_nsaved_regs ();
frame->nsseregs = ix86_nsaved_sseregs ();
- /* 64-bit MS ABI seem to require stack alignment to be always 16 except for
- function prologues and leaf. */
+ /* 64-bit MS ABI seem to require stack alignment to be always 16,
+ except for function prologues, leaf functions and when the defult
+ incoming stack boundary is overriden at command line or via
+ force_align_arg_pointer attribute. */
if ((TARGET_64BIT_MS_ABI && crtl->preferred_stack_boundary < 128)
&& (!crtl->is_leaf || cfun->calls_alloca != 0
- || ix86_current_function_calls_tls_descriptor))
+ || ix86_current_function_calls_tls_descriptor
+ || ix86_incoming_stack_boundary < 128))
{
crtl->preferred_stack_boundary = 128;
crtl->stack_alignment_needed = 128;
Hello! As said in the PR: -mstackrealign is a new functionality on MS_ABI targets, and there are some places in the compiler that assume that these targets are always aligned to 16bytes. This alignment is in fact mandated by ABI, and all deviations can be considered ABI violations. However, we can relax this restriction in order to handle rough applications that misalign the stack, but this should in general be an exception, not the rule. Even if -mstackrealign can be declared as unsupported on MS_ABI targets, the infrastructure handles realignment just fine also for MS_ABI targets, we just need to enable correct code paths when incoming stack boundary is less than 16 bytes. This is exactly what the attached patch does. 2015-10-21 Uros Bizjak <ubizjak@gmail.com> PR target/68018 * config/i386/i386.c (ix86_compute_frame_layout): Realign the stack for 64-bit MS_ABI targets also when default incoming stack boundary is overriden. testsuite/ChangeLog: 2015-10-21 Uros Bizjak <ubizjak@gmail.com> PR target/68018 * gcc.target/i386/pr68018.c: New test. Patch was bootstrapped and regression tested on x86_64-linux-gnu {,-m32}, committed to mainline SVN. Uros.