From f174328efedff73f53cad8848fe69f92e940309a Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Tue, 5 Sep 2017 16:39:24 +0000 Subject: [PATCH] i386: Avoid stack realignment if possible ix86_finalize_stack_frame_flags has been extended to eliminate frame pointer when the new stack frame isn't needed with and without -maccumulate-outgoing-args as well as -fomit-frame-pointer. Since stack access with larger alignment may be optimized out, to decide if stack realignment is needed, we need to not only check for stack frame access, but also verify the alignment of stack frame access. Since alignment of memory access via arg_pointer is set up by caller, not by callee, we should find the maximum stack alignment from the stack frame access instructions via stack pointer and frame pointrer to avoid stack realignment when stack alignment needed is less than incoming stack boundary. gcc/ PR target/59501 PR target/81624 PR target/81769 * config/i386/i386.c (ix86_finalize_stack_frame_flags): Don't realign stack if stack alignment needed is less than incoming stack boundary. gcc/testsuite/ PR target/59501 PR target/81624 PR target/81769 * gcc.target/i386/pr59501-4a.c: Remove xfail. * gcc.target/i386/pr81769-1a.c: New test. * gcc.target/i386/pr81769-1b.c: Likewise. * gcc.target/i386/pr81769-2.c: Likewise. From-SVN: r251718 --- gcc/ChangeLog | 9 ++ gcc/config/i386/i386.c | 143 +++++++++++++-------- gcc/testsuite/ChangeLog | 10 ++ gcc/testsuite/gcc.target/i386/pr59501-4a.c | 2 +- gcc/testsuite/gcc.target/i386/pr81769-1a.c | 21 +++ gcc/testsuite/gcc.target/i386/pr81769-1b.c | 7 + gcc/testsuite/gcc.target/i386/pr81769-2.c | 21 +++ 7 files changed, 157 insertions(+), 56 deletions(-) create mode 100644 gcc/testsuite/gcc.target/i386/pr81769-1a.c create mode 100644 gcc/testsuite/gcc.target/i386/pr81769-1b.c create mode 100644 gcc/testsuite/gcc.target/i386/pr81769-2.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 2f6983ffa9e..fa34e13bc4e 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,12 @@ +2017-09-05 H.J. Lu + + PR target/59501 + PR target/81624 + PR target/81769 + * config/i386/i386.c (ix86_finalize_stack_frame_flags): Don't + realign stack if stack alignment needed is less than incoming + stack boundary. + 2017-09-05 Marek Polacek PR sanitizer/82072 diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c index 6fdc9fd54b1..74064510c63 100644 --- a/gcc/config/i386/i386.c +++ b/gcc/config/i386/i386.c @@ -14303,6 +14303,11 @@ ix86_finalize_stack_frame_flags (void) add_to_hard_reg_set (&set_up_by_prologue, Pmode, ARG_POINTER_REGNUM); add_to_hard_reg_set (&set_up_by_prologue, Pmode, HARD_FRAME_POINTER_REGNUM); + + /* The preferred stack alignment is the minimum stack alignment. */ + unsigned int stack_alignment = crtl->preferred_stack_boundary; + bool require_stack_frame = false; + FOR_EACH_BB_FN (bb, cfun) { rtx_insn *insn; @@ -14311,79 +14316,107 @@ ix86_finalize_stack_frame_flags (void) && requires_stack_frame_p (insn, prologue_used, set_up_by_prologue)) { - if (crtl->stack_realign_needed != stack_realign) - recompute_frame_layout_p = true; - crtl->stack_realign_needed = stack_realign; - crtl->stack_realign_finalized = true; - if (recompute_frame_layout_p) - ix86_compute_frame_layout (); - return; + require_stack_frame = true; + + if (stack_realign) + { + /* Find the maximum stack alignment. */ + subrtx_iterator::array_type array; + FOR_EACH_SUBRTX (iter, array, PATTERN (insn), ALL) + if (MEM_P (*iter) + && (reg_mentioned_p (stack_pointer_rtx, + *iter) + || reg_mentioned_p (frame_pointer_rtx, + *iter))) + { + unsigned int alignment = MEM_ALIGN (*iter); + if (alignment > stack_alignment) + stack_alignment = alignment; + } + } } } - /* If drap has been set, but it actually isn't live at the start - of the function, there is no reason to set it up. */ - if (crtl->drap_reg) + if (require_stack_frame) { - basic_block bb = ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb; - if (! REGNO_REG_SET_P (DF_LR_IN (bb), REGNO (crtl->drap_reg))) + /* Stack frame is required. If stack alignment needed is less + than incoming stack boundary, don't realign stack. */ + stack_realign = incoming_stack_boundary < stack_alignment; + if (!stack_realign) { - crtl->drap_reg = NULL_RTX; - crtl->need_drap = false; + crtl->max_used_stack_slot_alignment + = incoming_stack_boundary; + crtl->stack_alignment_needed + = incoming_stack_boundary; } } else - cfun->machine->no_drap_save_restore = true; - - frame_pointer_needed = false; - stack_realign = false; - crtl->max_used_stack_slot_alignment = incoming_stack_boundary; - crtl->stack_alignment_needed = incoming_stack_boundary; - crtl->stack_alignment_estimated = incoming_stack_boundary; - if (crtl->preferred_stack_boundary > incoming_stack_boundary) - crtl->preferred_stack_boundary = incoming_stack_boundary; - df_finish_pass (true); - df_scan_alloc (NULL); - df_scan_blocks (); - df_compute_regs_ever_live (true); - df_analyze (); - - if (flag_var_tracking) { - /* Since frame pointer is no longer available, replace it with - stack pointer - UNITS_PER_WORD in debug insns. */ - df_ref ref, next; - for (ref = DF_REG_USE_CHAIN (HARD_FRAME_POINTER_REGNUM); - ref; ref = next) + /* If drap has been set, but it actually isn't live at the + start of the function, there is no reason to set it up. */ + if (crtl->drap_reg) { - rtx_insn *insn = DF_REF_INSN (ref); - /* Make sure the next ref is for a different instruction, - so that we're not affected by the rescan. */ - next = DF_REF_NEXT_REG (ref); - while (next && DF_REF_INSN (next) == insn) - next = DF_REF_NEXT_REG (next); - - if (DEBUG_INSN_P (insn)) + basic_block bb = ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb; + if (! REGNO_REG_SET_P (DF_LR_IN (bb), + REGNO (crtl->drap_reg))) + { + crtl->drap_reg = NULL_RTX; + crtl->need_drap = false; + } + } + else + cfun->machine->no_drap_save_restore = true; + + frame_pointer_needed = false; + stack_realign = false; + crtl->max_used_stack_slot_alignment = incoming_stack_boundary; + crtl->stack_alignment_needed = incoming_stack_boundary; + crtl->stack_alignment_estimated = incoming_stack_boundary; + if (crtl->preferred_stack_boundary > incoming_stack_boundary) + crtl->preferred_stack_boundary = incoming_stack_boundary; + df_finish_pass (true); + df_scan_alloc (NULL); + df_scan_blocks (); + df_compute_regs_ever_live (true); + df_analyze (); + + if (flag_var_tracking) + { + /* Since frame pointer is no longer available, replace it with + stack pointer - UNITS_PER_WORD in debug insns. */ + df_ref ref, next; + for (ref = DF_REG_USE_CHAIN (HARD_FRAME_POINTER_REGNUM); + ref; ref = next) { - bool changed = false; - for (; ref != next; ref = DF_REF_NEXT_REG (ref)) + rtx_insn *insn = DF_REF_INSN (ref); + /* Make sure the next ref is for a different instruction, + so that we're not affected by the rescan. */ + next = DF_REF_NEXT_REG (ref); + while (next && DF_REF_INSN (next) == insn) + next = DF_REF_NEXT_REG (next); + + if (DEBUG_INSN_P (insn)) { - rtx *loc = DF_REF_LOC (ref); - if (*loc == hard_frame_pointer_rtx) + bool changed = false; + for (; ref != next; ref = DF_REF_NEXT_REG (ref)) { - *loc = plus_constant (Pmode, - stack_pointer_rtx, - -UNITS_PER_WORD); - changed = true; + rtx *loc = DF_REF_LOC (ref); + if (*loc == hard_frame_pointer_rtx) + { + *loc = plus_constant (Pmode, + stack_pointer_rtx, + -UNITS_PER_WORD); + changed = true; + } } + if (changed) + df_insn_rescan (insn); } - if (changed) - df_insn_rescan (insn); } } - } - recompute_frame_layout_p = true; + recompute_frame_layout_p = true; + } } if (crtl->stack_realign_needed != stack_realign) diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 623e41417f9..a34c6923a0e 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,13 @@ +2017-09-05 H.J. Lu + + PR target/59501 + PR target/81624 + PR target/81769 + * gcc.target/i386/pr59501-4a.c: Remove xfail. + * gcc.target/i386/pr81769-1a.c: New test. + * gcc.target/i386/pr81769-1b.c: Likewise. + * gcc.target/i386/pr81769-2.c: Likewise. + 2017-09-05 Marek Polacek PR sanitizer/82072 diff --git a/gcc/testsuite/gcc.target/i386/pr59501-4a.c b/gcc/testsuite/gcc.target/i386/pr59501-4a.c index 5c3cb683a2e..908c7f457b6 100644 --- a/gcc/testsuite/gcc.target/i386/pr59501-4a.c +++ b/gcc/testsuite/gcc.target/i386/pr59501-4a.c @@ -5,4 +5,4 @@ #include "pr59501-3a.c" /* Verify no dynamic realignment is performed. */ -/* { dg-final { scan-assembler-not "and\[^\n\r]*sp" { xfail *-*-* } } } */ +/* { dg-final { scan-assembler-not "and\[^\n\r]*sp" } } */ diff --git a/gcc/testsuite/gcc.target/i386/pr81769-1a.c b/gcc/testsuite/gcc.target/i386/pr81769-1a.c new file mode 100644 index 00000000000..8ebe7292184 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr81769-1a.c @@ -0,0 +1,21 @@ +/* { dg-do compile } */ +/* { dg-options "-O -mavx" } */ + +typedef int v8si __attribute__ ((vector_size (32))); +typedef unsigned long long int u64 __attribute__ ((aligned(64))); + + +void +#ifndef __x86_64__ +__attribute__((regparm(3))) +#endif +foo (u64 *idx, v8si *out_start, v8si *regions) +{ + if (*idx < 20 ) { + v8si base = regions[*idx]; + *out_start = base; + } +} + +/* Verify no dynamic realignment is performed. */ +/* { dg-final { scan-assembler-not "and\[^\n\r]*sp" } } */ diff --git a/gcc/testsuite/gcc.target/i386/pr81769-1b.c b/gcc/testsuite/gcc.target/i386/pr81769-1b.c new file mode 100644 index 00000000000..6505a5f0074 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr81769-1b.c @@ -0,0 +1,7 @@ +/* { dg-do compile } */ +/* { dg-options "-O -mavx -fno-omit-frame-pointer" } */ + +#include "pr81769-1a.c" + +/* Verify no dynamic realignment is performed. */ +/* { dg-final { scan-assembler-not "and\[^\n\r]*sp" } } */ diff --git a/gcc/testsuite/gcc.target/i386/pr81769-2.c b/gcc/testsuite/gcc.target/i386/pr81769-2.c new file mode 100644 index 00000000000..e020db20227 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr81769-2.c @@ -0,0 +1,21 @@ +/* { dg-do compile } */ +/* { dg-options "-O -mavx -fno-omit-frame-pointer" } */ + +typedef unsigned long long int u64 __attribute__ ((aligned(64))); + +void +#ifndef __x86_64__ +__attribute__((regparm(3))) +#endif +foo (u64 *idx, unsigned int *out_start, unsigned int *out_end, + unsigned int *regions) +{ + if (*idx < 20 ) { + unsigned int base = regions[*idx]; + *out_start = base; + *out_end = base; + } +} + +/* Verify no dynamic realignment is performed. */ +/* { dg-final { scan-assembler-not "and\[^\n\r]*sp" } } */ -- 2.30.2