From: H.J. Lu Date: Wed, 22 May 2019 18:53:37 +0000 (+0000) Subject: x86: Don't allocate stack frame nor align stack if not needed X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=c2080a1fb549a99d567ff6834e06163fb883bf54;p=gcc.git 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 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 446c2d458ca..5ee574683fc 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,19 @@ +2019-05-22 H.J. Lu + + 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. + 2019-05-22 Uroš Bizjak * config/i386/sse.md (sse_cvtpi2ps): Use TARGET_MMX in insn condition. diff --git a/gcc/config/i386/i386-options.c b/gcc/config/i386/i386-options.c index bde104879cb..0f236626005 100644 --- a/gcc/config/i386/i386-options.c +++ b/gcc/config/i386/i386-options.c @@ -1537,6 +1537,7 @@ ix86_init_machine_status (void) f = ggc_cleared_alloc (); f->call_abi = ix86_abi; + f->stack_frame_required = true; return f; } diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c index 54607748b0b..463e78112f0 100644 --- a/gcc/config/i386/i386.c +++ b/gcc/config/i386/i386.c @@ -5012,6 +5012,19 @@ ix86_can_use_return_insn_p (void) && (frame.nregs + frame.nsseregs) == 0); } +/* Return stack frame size. get_frame_size () returns used stack slots + during compilation, which may be optimized out later. If stack frame + is needed, stack_frame_required should be true. */ + +static HOST_WIDE_INT +ix86_get_frame_size (void) +{ + if (cfun->machine->stack_frame_required) + return get_frame_size (); + else + return 0; +} + /* Value should be nonzero if functions must have frame pointers. Zero means the frame pointer need not be set up (and parms may be accessed via the stack pointer) in functions that seem suitable. */ @@ -5035,7 +5048,7 @@ ix86_frame_pointer_required (void) /* Win64 SEH, very large frames need a frame-pointer as maximum stack allocation is 4GB. */ - if (TARGET_64BIT_MS_ABI && get_frame_size () > SEH_MAX_FRAME_SIZE) + if (TARGET_64BIT_MS_ABI && ix86_get_frame_size () > SEH_MAX_FRAME_SIZE) return true; /* SSE saves require frame-pointer when stack is misaligned. */ @@ -5842,7 +5855,7 @@ ix86_compute_frame_layout (void) unsigned HOST_WIDE_INT stack_alignment_needed; HOST_WIDE_INT offset; unsigned HOST_WIDE_INT preferred_alignment; - HOST_WIDE_INT size = get_frame_size (); + HOST_WIDE_INT size = ix86_get_frame_size (); HOST_WIDE_INT to_allocate; /* m->call_ms2sysv is initially enabled in ix86_expand_call for all 64-bit @@ -7436,11 +7449,11 @@ output_probe_stack_range (rtx reg, rtx end) return ""; } -/* Return true if stack frame is required. Update STACK_ALIGNMENT - to the largest alignment, in bits, of stack slot used if stack - frame is required and CHECK_STACK_SLOT is true. */ +/* Set stack_frame_required to false if stack frame isn't required. + Update STACK_ALIGNMENT to the largest alignment, in bits, of stack + slot used if stack frame is required and CHECK_STACK_SLOT is true. */ -static bool +static void ix86_find_max_used_stack_alignment (unsigned int &stack_alignment, bool check_stack_slot) { @@ -7489,7 +7502,7 @@ ix86_find_max_used_stack_alignment (unsigned int &stack_alignment, } } - return require_stack_frame; + cfun->machine->stack_frame_required = require_stack_frame; } /* Finalize stack_realign_needed and frame_pointer_needed flags, which @@ -7519,6 +7532,14 @@ ix86_finalize_stack_frame_flags (void) return; } + /* It is always safe to compute max_used_stack_alignment. We + compute it only if 128-bit aligned load/store may be generated + on misaligned stack slot which will lead to segfault. */ + bool check_stack_slot + = (stack_realign || crtl->max_used_stack_slot_alignment >= 128); + ix86_find_max_used_stack_alignment (stack_alignment, + check_stack_slot); + /* If the only reason for frame_pointer_needed is that we conservatively assumed stack realignment might be needed or -fno-omit-frame-pointer is used, but in the end nothing that needed the stack alignment had @@ -7538,12 +7559,11 @@ ix86_finalize_stack_frame_flags (void) && flag_exceptions && cfun->can_throw_non_call_exceptions) && !ix86_frame_pointer_required () - && get_frame_size () == 0 + && ix86_get_frame_size () == 0 && ix86_nsaved_sseregs () == 0 && ix86_varargs_gpr_size + ix86_varargs_fpr_size == 0) { - if (ix86_find_max_used_stack_alignment (stack_alignment, - stack_realign)) + if (cfun->machine->stack_frame_required) { /* Stack frame is required. If stack alignment needed is less than incoming stack boundary, don't realign stack. */ @@ -7631,17 +7651,14 @@ ix86_finalize_stack_frame_flags (void) recompute_frame_layout_p = true; } } - else if (crtl->max_used_stack_slot_alignment >= 128) + else if (crtl->max_used_stack_slot_alignment >= 128 + && cfun->machine->stack_frame_required) { /* We don't need to realign stack. max_used_stack_alignment is used to decide how stack frame should be aligned. This is - independent of any psABIs nor 32-bit vs 64-bit. It is always - safe to compute max_used_stack_alignment. We compute it only - if 128-bit aligned load/store may be generated on misaligned - stack slot which will lead to segfault. */ - if (ix86_find_max_used_stack_alignment (stack_alignment, true)) - cfun->machine->max_used_stack_alignment - = stack_alignment / BITS_PER_UNIT; + independent of any psABIs nor 32-bit vs 64-bit. */ + cfun->machine->max_used_stack_alignment + = stack_alignment / BITS_PER_UNIT; } if (crtl->stack_realign_needed != stack_realign) diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h index be1480fdcf8..7852c766f77 100644 --- a/gcc/config/i386/i386.h +++ b/gcc/config/i386/i386.h @@ -2754,6 +2754,9 @@ struct GTY(()) machine_function { /* If true, ENDBR is queued at function entrance. */ BOOL_BITFIELD endbr_queued_at_entrance : 1; + /* True if the function needs a stack frame. */ + BOOL_BITFIELD stack_frame_required : 1; + /* The largest alignment, in bytes, of stack slot actually used. */ unsigned int max_used_stack_alignment; diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 2d7fc64042b..86ef3b60886 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,9 @@ +2019-05-22 H.J. Lu + + PR target/88483 + * gcc.target/i386/stackalign/pr88483-1.c: New test. + * gcc.target/i386/stackalign/pr88483-2.c: Likewise. + 2019-05-22 Andrew Stubbs * gfortran.dg/coarray_lock_7.f90: Fix output patterns. diff --git a/gcc/testsuite/gcc.target/i386/stackalign/pr88483-1.c b/gcc/testsuite/gcc.target/i386/stackalign/pr88483-1.c new file mode 100644 index 00000000000..c8bb0832fe2 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/stackalign/pr88483-1.c @@ -0,0 +1,18 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -mavx2" } */ + +struct B +{ + char a[12]; + int b; +}; + +struct B +f2 (void) +{ + struct B x = {}; + return x; +} + +/* { dg-final { scan-assembler-not "(sub|add)(l|q)\[\\t \]*\\$\[0-9\]*,\[\\t \]*%\[re\]?sp" } } */ +/* { dg-final { scan-assembler-not "and\[lq\]?\[^\\n\]*-\[0-9\]+,\[^\\n\]*sp" } } */ diff --git a/gcc/testsuite/gcc.target/i386/stackalign/pr88483-2.c b/gcc/testsuite/gcc.target/i386/stackalign/pr88483-2.c new file mode 100644 index 00000000000..e94fa1d18fa --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/stackalign/pr88483-2.c @@ -0,0 +1,18 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -mavx512f" } */ + +struct B +{ + char a[12]; + int b; +}; + +struct B +f2 (void) +{ + struct B x = {}; + return x; +} + +/* { dg-final { scan-assembler-not "(sub|add)(l|q)\[\\t \]*\\$\[0-9\]*,\[\\t \]*%\[re\]?sp" } } */ +/* { dg-final { scan-assembler-not "and\[lq\]?\[^\\n\]*-\[0-9\]+,\[^\\n\]*sp" } } */