x86: Don't allocate stack frame nor align stack if not needed
get_frame_size () returns used stack slots during compilation, which may be optimized out later. This patch does the followings: 1. Add stack_frame_required to machine_function to indicate that the function needs a stack frame. 2. Change ix86_find_max_used_stack_alignment to set stack_frame_required. 3. Always call ix86_find_max_used_stack_alignment to check if stack frame is needed. Tested on i686 and x86-64 with --with-arch=native --with-cpu=native Tested on AVX512 machine configured with --with-arch=native --with-cpu=native gcc/ PR target/88483 * config/i386/i386-options.c (ix86_init_machine_status): Set stack_frame_required to true. * config/i386/i386.c (ix86_get_frame_size): New function. (ix86_frame_pointer_required): Replace get_frame_size with ix86_get_frame_size. (ix86_compute_frame_layout): Likewise. (ix86_find_max_used_stack_alignment): Changed to void. Set stack_frame_required. (ix86_finalize_stack_frame_flags): Always call ix86_find_max_used_stack_alignment. Replace get_frame_size with ix86_get_frame_size. * config/i386/i386.h (machine_function): Add stack_frame_required. gcc/testsuite/ PR target/88483 * gcc.target/i386/stackalign/pr88483-1.c: New test. * gcc.target/i386/stackalign/pr88483-2.c: Likewise. From-SVN: r271517
This commit is contained in:
H.J. Lu
H.J. Lu
parent
586e53e269
commit
c2080a1fb5
7 changed files with 97 additions and 18 deletions
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@ -1,3 +1,19 @@
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2019-05-22 H.J. Lu <hongjiu.lu@intel.com>
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PR target/88483
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* config/i386/i386-options.c (ix86_init_machine_status): Set
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stack_frame_required to true.
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* config/i386/i386.c (ix86_get_frame_size): New function.
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(ix86_frame_pointer_required): Replace get_frame_size with
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ix86_get_frame_size.
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(ix86_compute_frame_layout): Likewise.
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(ix86_find_max_used_stack_alignment): Changed to void. Set
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stack_frame_required.
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(ix86_finalize_stack_frame_flags): Always call
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ix86_find_max_used_stack_alignment. Replace get_frame_size with
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ix86_get_frame_size.
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* config/i386/i386.h (machine_function): Add stack_frame_required.
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2019-05-22 Uroš Bizjak <ubizjak@gmail.com>
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* config/i386/sse.md (sse_cvtpi2ps): Use TARGET_MMX in insn condition.
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@ -1537,6 +1537,7 @@ ix86_init_machine_status (void)
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f = ggc_cleared_alloc<machine_function> ();
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f->call_abi = ix86_abi;
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f->stack_frame_required = true;
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return f;
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}
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@ -5012,6 +5012,19 @@ ix86_can_use_return_insn_p (void)
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&& (frame.nregs + frame.nsseregs) == 0);
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}
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/* Return stack frame size. get_frame_size () returns used stack slots
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during compilation, which may be optimized out later. If stack frame
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is needed, stack_frame_required should be true. */
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static HOST_WIDE_INT
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ix86_get_frame_size (void)
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{
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if (cfun->machine->stack_frame_required)
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return get_frame_size ();
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else
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return 0;
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}
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/* Value should be nonzero if functions must have frame pointers.
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Zero means the frame pointer need not be set up (and parms may
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be accessed via the stack pointer) in functions that seem suitable. */
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@ -5035,7 +5048,7 @@ ix86_frame_pointer_required (void)
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/* Win64 SEH, very large frames need a frame-pointer as maximum stack
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allocation is 4GB. */
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if (TARGET_64BIT_MS_ABI && get_frame_size () > SEH_MAX_FRAME_SIZE)
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if (TARGET_64BIT_MS_ABI && ix86_get_frame_size () > SEH_MAX_FRAME_SIZE)
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return true;
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/* SSE saves require frame-pointer when stack is misaligned. */
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@ -5842,7 +5855,7 @@ ix86_compute_frame_layout (void)
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unsigned HOST_WIDE_INT stack_alignment_needed;
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HOST_WIDE_INT offset;
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unsigned HOST_WIDE_INT preferred_alignment;
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HOST_WIDE_INT size = get_frame_size ();
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HOST_WIDE_INT size = ix86_get_frame_size ();
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HOST_WIDE_INT to_allocate;
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/* m->call_ms2sysv is initially enabled in ix86_expand_call for all 64-bit
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@ -7436,11 +7449,11 @@ output_probe_stack_range (rtx reg, rtx end)
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return "";
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}
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/* Return true if stack frame is required. Update STACK_ALIGNMENT
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to the largest alignment, in bits, of stack slot used if stack
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frame is required and CHECK_STACK_SLOT is true. */
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/* Set stack_frame_required to false if stack frame isn't required.
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Update STACK_ALIGNMENT to the largest alignment, in bits, of stack
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slot used if stack frame is required and CHECK_STACK_SLOT is true. */
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static bool
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static void
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ix86_find_max_used_stack_alignment (unsigned int &stack_alignment,
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bool check_stack_slot)
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{
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@ -7489,7 +7502,7 @@ ix86_find_max_used_stack_alignment (unsigned int &stack_alignment,
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}
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}
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return require_stack_frame;
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cfun->machine->stack_frame_required = require_stack_frame;
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}
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/* Finalize stack_realign_needed and frame_pointer_needed flags, which
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@ -7519,6 +7532,14 @@ ix86_finalize_stack_frame_flags (void)
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return;
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}
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/* It is always safe to compute max_used_stack_alignment. We
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compute it only if 128-bit aligned load/store may be generated
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on misaligned stack slot which will lead to segfault. */
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bool check_stack_slot
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= (stack_realign || crtl->max_used_stack_slot_alignment >= 128);
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ix86_find_max_used_stack_alignment (stack_alignment,
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check_stack_slot);
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/* If the only reason for frame_pointer_needed is that we conservatively
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assumed stack realignment might be needed or -fno-omit-frame-pointer
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is used, but in the end nothing that needed the stack alignment had
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@ -7538,12 +7559,11 @@ ix86_finalize_stack_frame_flags (void)
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&& flag_exceptions
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&& cfun->can_throw_non_call_exceptions)
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&& !ix86_frame_pointer_required ()
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&& get_frame_size () == 0
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&& ix86_get_frame_size () == 0
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&& ix86_nsaved_sseregs () == 0
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&& ix86_varargs_gpr_size + ix86_varargs_fpr_size == 0)
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{
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if (ix86_find_max_used_stack_alignment (stack_alignment,
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stack_realign))
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if (cfun->machine->stack_frame_required)
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{
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/* Stack frame is required. If stack alignment needed is less
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than incoming stack boundary, don't realign stack. */
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@ -7631,15 +7651,12 @@ ix86_finalize_stack_frame_flags (void)
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recompute_frame_layout_p = true;
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}
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}
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else if (crtl->max_used_stack_slot_alignment >= 128)
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else if (crtl->max_used_stack_slot_alignment >= 128
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&& cfun->machine->stack_frame_required)
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{
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/* We don't need to realign stack. max_used_stack_alignment is
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used to decide how stack frame should be aligned. This is
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independent of any psABIs nor 32-bit vs 64-bit. It is always
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safe to compute max_used_stack_alignment. We compute it only
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if 128-bit aligned load/store may be generated on misaligned
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stack slot which will lead to segfault. */
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if (ix86_find_max_used_stack_alignment (stack_alignment, true))
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independent of any psABIs nor 32-bit vs 64-bit. */
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cfun->machine->max_used_stack_alignment
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= stack_alignment / BITS_PER_UNIT;
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}
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@ -2754,6 +2754,9 @@ struct GTY(()) machine_function {
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/* If true, ENDBR is queued at function entrance. */
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BOOL_BITFIELD endbr_queued_at_entrance : 1;
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/* True if the function needs a stack frame. */
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BOOL_BITFIELD stack_frame_required : 1;
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/* The largest alignment, in bytes, of stack slot actually used. */
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unsigned int max_used_stack_alignment;
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@ -1,3 +1,9 @@
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2019-05-22 H.J. Lu <hongjiu.lu@intel.com>
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PR target/88483
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* gcc.target/i386/stackalign/pr88483-1.c: New test.
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* gcc.target/i386/stackalign/pr88483-2.c: Likewise.
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2019-05-22 Andrew Stubbs <ams@codesourcery.com>
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* gfortran.dg/coarray_lock_7.f90: Fix output patterns.
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18
gcc/testsuite/gcc.target/i386/stackalign/pr88483-1.c
Normal file
18
gcc/testsuite/gcc.target/i386/stackalign/pr88483-1.c
Normal file
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@ -0,0 +1,18 @@
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/* { dg-do compile } */
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/* { dg-options "-O2 -mavx2" } */
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struct B
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{
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char a[12];
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int b;
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};
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struct B
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f2 (void)
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{
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struct B x = {};
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return x;
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}
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/* { dg-final { scan-assembler-not "(sub|add)(l|q)\[\\t \]*\\$\[0-9\]*,\[\\t \]*%\[re\]?sp" } } */
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/* { dg-final { scan-assembler-not "and\[lq\]?\[^\\n\]*-\[0-9\]+,\[^\\n\]*sp" } } */
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18
gcc/testsuite/gcc.target/i386/stackalign/pr88483-2.c
Normal file
18
gcc/testsuite/gcc.target/i386/stackalign/pr88483-2.c
Normal file
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@ -0,0 +1,18 @@
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/* { dg-do compile } */
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/* { dg-options "-O2 -mavx512f" } */
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struct B
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{
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char a[12];
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int b;
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};
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struct B
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f2 (void)
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{
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struct B x = {};
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return x;
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}
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/* { dg-final { scan-assembler-not "(sub|add)(l|q)\[\\t \]*\\$\[0-9\]*,\[\\t \]*%\[re\]?sp" } } */
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/* { dg-final { scan-assembler-not "and\[lq\]?\[^\\n\]*-\[0-9\]+,\[^\\n\]*sp" } } */
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