The parameters fs->data_align and fs->code_align always have fixed
values for a particular target in GCC-generated code. Specialize
execute_cfa_program for these values, to avoid multiplications.
gcc/c-family/
* c-cppbuiltin.cc (c_cpp_builtins): Define
__LIBGCC_DWARF_CIE_DATA_ALIGNMENT__.
libgcc/
* unwind-dw2-execute_cfa.h: New file. Extracted from
the execute_cfa_program function in unwind-dw2.c.
* unwind-dw2.c (execute_cfa_program_generic): New function.
(execute_cfa_program_specialized): Likewise.
(execute_cfa_program): Call execute_cfa_program_specialized
or execute_cfa_program_generic, as appropriate.
The parameters fs->data_align and fs->code_align always have fixed
values for a particular target in GCC-generated code. Specialize
execute_cfa_program for these values, to avoid multiplications.
gcc/c-family/
* c-cppbuiltin.cc (c_cpp_builtins): Define
__LIBGCC_DWARF_CIE_DATA_ALIGNMENT__.
libgcc/
* unwind-dw2-execute_cfa.h: New file. Extracted from
the execute_cfa_program function in unwind-dw2.c.
* unwind-dw2.c (execute_cfa_program_generic): New function.
(execute_cfa_program_specialized): Likewise.
(execute_cfa_program): Call execute_cfa_program_specialized
or execute_cfa_program_generic, as appropriate.
And use that to speed up the libgcc unwinder.
gcc/
* debug.h (dwarf_reg_sizes_constant): Declare.
* dwarf2cfi.cc (dwarf_reg_sizes_constant): New function.
gcc/c-family/
* c-cppbuiltin.cc (__LIBGCC_DWARF_REG_SIZES_CONSTANT__):
Define if constant is known.
libgcc/
* unwind-dw2.c (dwarf_reg_size): New function.
(_Unwind_GetGR, _Unwind_SetGR, _Unwind_SetGRPtr)
(_Unwind_SetSpColumn, uw_install_context_1): Use it.
(uw_init_context_1): Do not initialize dwarf_reg_size_table
if not in use.
The following patch implements something that has Florian found as
low hanging fruit in our unwinder and has been discussed in the
https://gcc.gnu.org/wiki/cauldron2022#cauldron2022talks.inprocess_unwinding_bof
talk.
_Unwind_FrameState type seems to be (unlike the pre-GCC 3 frame_state
which has been part of ABI) private to unwind-dw2.c + unwind.inc it
includes, it is always defined on the stack of some entrypoints, initialized
by static uw_frame_state_for and the address of it is also passed to other
static functions or the static inlines handling machine dependent unwinding,
but it isn't fortunately passed to any callbacks or public functions, so I
think we can safely change it any time we want.
Florian mentioned that the structure is large even on x86_64, 384 bytes
there, starts with 328 bytes long element with frame_state_reg_info type
which then starts with an array with __LIBGCC_DWARF_FRAME_REGISTERS__ + 1
elements, each of them is 16 bytes long, on x86_64
__LIBGCC_DWARF_FRAME_REGISTERS__ is just 17 but even that is big, on say
riscv __LIBGCC_DWARF_FRAME_REGISTERS__ is I think 128, on powerpc 111,
on sh 153 etc. And, we memset to zero the whole fs variable with the
_Unwind_FrameState type at the start of the unwinding.
The reason why each element is 16 byte (on 64-bit arches) is that it
contains some pointer or pointer sized integer and then an enum (with just
7 different enumerators) + padding.
The following patch decreases it by moving the enum into a separate
array and using just one byte for each register in that second array.
We could compress it even more, say 4 bits per register, but I don't
want to uglify the code for it too much and make the accesses slower.
Furthermore, the clearing of the object can clear only thos how array
and members after it, because REG_UNSAVED enumerator (0) doesn't actually
need any pointer or pointer sized integer, it is just the other kinds
that need to have there something.
By doing this, on x86_64 the above numbers change to _Unwind_FrameState
type being now 264 bytes long, frame_state_reg_info 208 bytes and we
don't clear the first 144 bytes of the object, so the memset is 120 bytes,
so ~ 31% of the old clearing size. On riscv 64-bit assuming it has same
structure layout rules for the few types used there that would be
~ 2160 bytes of _Unwind_FrameState type before and ~ 1264 bytes after,
with the memset previously ~ 2160 bytes and after ~ 232 bytes after.
We've also talked about possibly adding a number of initially initialized
regs and initializing the rest lazily, but at least for x86_64 with
18 elements in the array that doesn't seem to be worth it anymore,
especially because return address column is 16 there and that is usually the
first thing to be touched. It might theory help with lots of registers if
they are usually untouched, but would uglify and complicate any stores to
how by having to check there for the not initialized yet cases and lazy
initialization, and similarly for all reads of how to do there if below
last initialized one, use how, otherwise imply REG_UNSAVED.
The disadvantage of the patch is that touching reg[x].loc and how[x]
now means 2 cachelines rather than one as before, and I admit beyond
bootstrap/regtest I haven't benchmarked it in any way.
2022-10-06 Jakub Jelinek <jakub@redhat.com>
* unwind-dw2.h (REG_UNSAVED, REG_SAVED_OFFSET, REG_SAVED_REG,
REG_SAVED_EXP, REG_SAVED_VAL_OFFSET, REG_SAVED_VAL_EXP,
REG_UNDEFINED): New anonymous enum, moved from inside of
struct frame_state_reg_info.
(struct frame_state_reg_info): Remove reg[].how element and the
anonymous enum there. Add how element.
* unwind-dw2.c: Include stddef.h.
(uw_frame_state_for): Don't clear first
offsetof (_Unwind_FrameState, regs.how[0]) bytes of *fs.
(execute_cfa_program, __frame_state_for, uw_update_context_1,
uw_update_context): Use fs->regs.how[X] instead of fs->regs.reg[X].how
or fs.regs.how[X] instead of fs.regs.reg[X].how.
* config/sh/linux-unwind.h (sh_fallback_frame_state): Likewise.
* config/bfin/linux-unwind.h (bfin_fallback_frame_state): Likewise.
* config/pa/linux-unwind.h (pa32_fallback_frame_state): Likewise.
* config/pa/hpux-unwind.h (UPDATE_FS_FOR_SAR, UPDATE_FS_FOR_GR,
UPDATE_FS_FOR_FR, UPDATE_FS_FOR_PC, pa_fallback_frame_state):
Likewise.
* config/alpha/vms-unwind.h (alpha_vms_fallback_frame_state):
Likewise.
* config/alpha/linux-unwind.h (alpha_fallback_frame_state): Likewise.
* config/arc/linux-unwind.h (arc_fallback_frame_state,
arc_frob_update_context): Likewise.
* config/riscv/linux-unwind.h (riscv_fallback_frame_state): Likewise.
* config/nios2/linux-unwind.h (NIOS2_REG): Likewise.
* config/nds32/linux-unwind.h (NDS32_PUT_FS_REG): Likewise.
* config/s390/tpf-unwind.h (s390_fallback_frame_state): Likewise.
* config/s390/linux-unwind.h (s390_fallback_frame_state): Likewise.
* config/sparc/sol2-unwind.h (sparc64_frob_update_context,
MD_FALLBACK_FRAME_STATE_FOR): Likewise.
* config/sparc/linux-unwind.h (sparc64_fallback_frame_state,
sparc64_frob_update_context, sparc_fallback_frame_state): Likewise.
* config/i386/sol2-unwind.h (x86_64_fallback_frame_state,
x86_fallback_frame_state): Likewise.
* config/i386/w32-unwind.h (i386_w32_fallback_frame_state): Likewise.
* config/i386/linux-unwind.h (x86_64_fallback_frame_state,
x86_fallback_frame_state): Likewise.
* config/i386/freebsd-unwind.h (x86_64_freebsd_fallback_frame_state):
Likewise.
* config/i386/dragonfly-unwind.h
(x86_64_dragonfly_fallback_frame_state): Likewise.
* config/i386/gnu-unwind.h (x86_gnu_fallback_frame_state): Likewise.
* config/csky/linux-unwind.h (csky_fallback_frame_state): Likewise.
* config/aarch64/linux-unwind.h (aarch64_fallback_frame_state):
Likewise.
* config/aarch64/freebsd-unwind.h
(aarch64_freebsd_fallback_frame_state): Likewise.
* config/aarch64/aarch64-unwind.h (aarch64_frob_update_context):
Likewise.
* config/or1k/linux-unwind.h (or1k_fallback_frame_state): Likewise.
* config/mips/linux-unwind.h (mips_fallback_frame_state): Likewise.
* config/loongarch/linux-unwind.h (loongarch_fallback_frame_state):
Likewise.
* config/m68k/linux-unwind.h (m68k_fallback_frame_state): Likewise.
* config/xtensa/linux-unwind.h (xtensa_fallback_frame_state):
Likewise.
* config/rs6000/darwin-fallback.c (set_offset): Likewise.
* config/rs6000/aix-unwind.h (MD_FROB_UPDATE_CONTEXT): Likewise.
* config/rs6000/linux-unwind.h (ppc_fallback_frame_state): Likewise.
* config/rs6000/freebsd-unwind.h (frob_update_context): Likewise.
The RA_SIGN_STATE dwarf pseudo-register is normally only set using the
DW_CFA_AARCH64_negate_ra_state (== DW_CFA_window_save) operation which
toggles the return address signedness state (the default state is 0).
(It may be set by remember/restore_state CFI too, those save/restore
the state of all registers.)
However RA_SIGN_STATE can be set directly via DW_CFA_val_expression too.
GCC does not generate such CFI but some other compilers reportedly do.
Note: the toggle operation must not be mixed with other dwarf register
rule CFI within the same CIE and FDE.
In libgcc we assume REG_UNSAVED means the RA_STATE is set using toggle
operations, otherwise we assume its value is set by other CFI.
libgcc/ChangeLog:
PR target/104689
* config/aarch64/aarch64-unwind.h (aarch64_frob_update_context):
Handle the !REG_UNSAVED case.
* unwind-dw2.c (execute_cfa_program): Fail toggle if !REG_UNSAVED.
gcc/testsuite/ChangeLog:
PR target/104689
* gcc.target/aarch64/pr104689.c: New test.
Mangling, currently only used on AArch64 for return address signing,
is an internal representation that should not be exposed via
__builtin_return_address return value,
__builtin_eh_return handler argument,
_Unwind_DebugHook handler argument.
Note that a mangled address might not even fit into a void *, e.g.
with AArch64 ilp32 ABI the return address is stored as 64bit, so
the mangled return address cannot be accessed via _Unwind_GetPtr.
This patch changes the unwinder hooks as follows:
MD_POST_EXTRACT_ROOT_ADDR is removed: root address comes from
__builtin_return_address which is not mangled.
MD_POST_EXTRACT_FRAME_ADDR is renamed to MD_DEMANGLE_RETURN_ADDR,
it now operates on _Unwind_Word instead of void *, so the hook
should work when return address signing is enabled on AArch64 ilp32.
(But for that __builtin_aarch64_autia1716 should be fixed to operate
on 64bit input instead of a void *.)
MD_POST_FROB_EH_HANDLER_ADDR is removed: it is the responsibility of
__builtin_eh_return to do the mangling if necessary.
2020-07-13 Szabolcs Nagy <szabolcs.nagy@arm.com>
libgcc/ChangeLog:
PR target/94891
* config/aarch64/aarch64-unwind.h (MD_POST_EXTRACT_ROOT_ADDR): Remove.
(MD_POST_FROB_EH_HANDLER_ADDR): Remove.
(MD_POST_EXTRACT_FRAME_ADDR): Rename to ...
(MD_DEMANGLE_RETURN_ADDR): This.
(aarch64_post_extract_frame_addr): Rename to ...
(aarch64_demangle_return_addr): This.
(aarch64_post_frob_eh_handler_addr): Remove.
* unwind-dw2.c (uw_update_context): Demangle return address.
(uw_frob_return_addr): Remove.
This patch adds support for unwinding frames that use the SVE
pseudo VG register. We want this register to act like a normal
register if the CFI explicitly sets it, but want to provide a
default value otherwise. Computing the default value requires
an SVE target, so we only want to compute it on demand.
aarch64_vg uses a hard-coded .inst in order to avoid a build
dependency on binutils 2.28 or later.
2018-01-13 Richard Sandiford <richard.sandiford@linaro.org>
gcc/
* doc/tm.texi.in (DWARF_LAZY_REGISTER_VALUE): Document.
* doc/tm.texi: Regenerate.
libgcc/
* config/aarch64/value-unwind.h (aarch64_vg): New function.
(DWARF_LAZY_REGISTER_VALUE): Define.
* unwind-dw2.c (_Unwind_GetGR): Use DWARF_LAZY_REGISTER_VALUE
to provide a fallback register value.
gcc/testsuite/
* g++.target/aarch64/sve/aarch64-sve.exp: New harness.
* g++.target/aarch64/sve/catch_1.C: New test.
* g++.target/aarch64/sve/catch_2.C: Likewise.
* g++.target/aarch64/sve/catch_3.C: Likewise.
* g++.target/aarch64/sve/catch_4.C: Likewise.
* g++.target/aarch64/sve/catch_5.C: Likewise.
* g++.target/aarch64/sve/catch_6.C: Likewise.
Reviewed-by: James Greenhalgh <james.greenhalgh@arm.com>
From-SVN: r256615
Control-flow Enforcement Technology (CET), published by Intel,
introduces the Shadow Stack feature, which ensures a return from a
function is done to exactly the same location from where the function
was called. When EH is present the control-flow transfer may skip some
stack frames and the shadow stack has to be adjusted not to signal a
violation of a control-flow transfer. It's done by counting a number
of skiping frames and adjasting shadow stack pointer by this number.
Having new semantic of the 'ret' instruction if CET is supported in HW
the 'ret' instruction cannot be generated in ix86_expand_epilogue when
we are returning after EH is processed. Added a code in
ix86_expand_epilogue to adjust Shadow Stack pointer and to generate an
indirect jump instead of 'ret'. As sp register is used during this
adjustment thus the argument in pro_epilogue_adjust_stack is changed
to update cfa_reg based on whether control-flow instrumentation is set.
Without updating the cfa_reg field there is an assert later in dwarf2
pass related to mismatch the stack register and cfa_reg value.
gcc/
* config/i386/i386.c (ix86_expand_epilogue): Change simple
return to indirect jump for EH return if control-flow protection
is enabled. Change explicit 'false' argument in
pro_epilogue_adjust_stack with a value of flag_cf_protection.
* config/i386/i386.md (simple_return_indirect_internal): Remove
SImode restriction to support 64-bit.
libgcc/
* config/i386/linux-unwind.h: Include
config/i386/shadow-stack-unwind.h.
* config/i386/shadow-stack-unwind.h: New file.
* unwind-dw2.c: (uw_install_context): Add a frame parameter and
pass it to _Unwind_Frames_Extra.
* unwind-generic.h (_Unwind_Frames_Extra): New.
* unwind.inc (_Unwind_RaiseException_Phase2): Add frames_p
parameter. Add local variable frames to count number of frames.
(_Unwind_ForcedUnwind_Phase2): Likewise.
(_Unwind_RaiseException): Add local variable frames to count
number of frames, pass it to _Unwind_RaiseException_Phase2 and
uw_install_context.
(_Unwind_ForcedUnwind): Likewise.
(_Unwind_Resume): Likewise.
(_Unwind_Resume_or_Rethrow): Likewise.
From-SVN: r254876
libgcc/
* config/aarch64/aarch64-unwind.h: New file.
(DWARF_REGNUM_AARCH64_RA_STATE): Define.
(MD_POST_EXTRACT_ROOT_ADDR): New target marcro and define it on AArch64.
(MD_POST_EXTRACT_FRAME_ADDR): Likewise.
(MD_POST_FROB_EH_HANDLER_ADDR): Likewise.
(MD_FROB_UPDATE_CONTEXT): Define it on AArch64.
(aarch64_post_extract_frame_addr): New function.
(aarch64_post_frob_eh_handler_addr): New function.
(aarch64_frob_update_context): New function.
* config/aarch64/linux-unwind.h: Include aarch64-unwind.h
* config.host (aarch64*-*-elf, aarch64*-*-rtems*,
aarch64*-*-freebsd*):
Initialize md_unwind_header to include aarch64-unwind.h.
* unwind-dw2.c (struct _Unwind_Context): Define "RA_A_SIGNED_BIT".
(execute_cfa_program): Multiplex DW_CFA_GNU_window_save for
__aarch64__.
(uw_update_context): Honor MD_POST_EXTRACT_FRAME_ADDR.
(uw_init_context_1): Honor MD_POST_EXTRACT_ROOT_ADDR.
(uw_frob_return_addr): New function.
(uw_install_context): Use uw_frob_return_addr.
From-SVN: r244673
gcc/c-family:
* c-cppbuiltin.c (c_cpp_builtins): Also define
__LIBGCC_EH_TABLES_CAN_BE_READ_ONLY__,
__LIBGCC_EH_FRAME_SECTION_NAME__, __LIBGCC_JCR_SECTION_NAME__,
__LIBGCC_CTORS_SECTION_ASM_OP__, __LIBGCC_DTORS_SECTION_ASM_OP__,
__LIBGCC_TEXT_SECTION_ASM_OP__, __LIBGCC_INIT_SECTION_ASM_OP__,
__LIBGCC_INIT_ARRAY_SECTION_ASM_OP__,
__LIBGCC_STACK_GROWS_DOWNWARD__,
__LIBGCC_DONT_USE_BUILTIN_SETJMP__,
__LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__,
__LIBGCC_DWARF_FRAME_REGISTERS__,
__LIBGCC_EH_RETURN_STACKADJ_RTX__, __LIBGCC_JMP_BUF_SIZE__,
__LIBGCC_STACK_POINTER_REGNUM__ and
__LIBGCC_VTABLE_USES_DESCRIPTORS__ for -fbuilding-libgcc.
(builtin_define_with_value): Handle backslash-escaping in string
macro values.
libgcc:
* Makefile.in (CRTSTUFF_CFLAGS): Add -fbuilding-libgcc.
* config/aarch64/linux-unwind.h (STACK_POINTER_REGNUM): Change all
uses to __LIBGCC_STACK_POINTER_REGNUM__.
(DWARF_ALT_FRAME_RETURN_COLUMN): Change all uses to
__LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__.
* config/alpha/vms-unwind.h (DWARF_ALT_FRAME_RETURN_COLUMN):
Change use to __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__.
* config/cr16/unwind-cr16.c (STACK_GROWS_DOWNWARD): Change all
uses to __LIBGCC_STACK_GROWS_DOWNWARD__.
(DWARF_FRAME_REGISTERS): Change all uses to
__LIBGCC_DWARF_FRAME_REGISTERS__.
(EH_RETURN_STACKADJ_RTX): Change all uses to
__LIBGCC_EH_RETURN_STACKADJ_RTX__.
* config/cr16/unwind-dw2.h (DWARF_FRAME_REGISTERS): Change use to
__LIBGCC_DWARF_FRAME_REGISTERS__. Remove conditional definition.
* config/i386/cygming-crtbegin.c (EH_FRAME_SECTION_NAME): Change
use to __LIBGCC_EH_FRAME_SECTION_NAME__.
(JCR_SECTION_NAME): Change use to __LIBGCC_JCR_SECTION_NAME__.
* config/i386/cygming-crtend.c (EH_FRAME_SECTION_NAME): Change use
to __LIBGCC_EH_FRAME_SECTION_NAME__.
(JCR_SECTION_NAME): Change use to __LIBGCC_JCR_SECTION_NAME__
* config/mips/linux-unwind.h (STACK_POINTER_REGNUM): Change use to
__LIBGCC_STACK_POINTER_REGNUM__.
(DWARF_ALT_FRAME_RETURN_COLUMN): Change all uses to
__LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__.
* config/nios2/linux-unwind.h (STACK_POINTER_REGNUM): Change use
to __LIBGCC_STACK_POINTER_REGNUM__.
* config/pa/hpux-unwind.h (DWARF_ALT_FRAME_RETURN_COLUMN): Change
all uses to __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__.
* config/pa/linux-unwind.h (DWARF_ALT_FRAME_RETURN_COLUMN): Change
all uses to __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__.
* config/rs6000/aix-unwind.h (DWARF_ALT_FRAME_RETURN_COLUMN):
Change all uses to __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__.
(STACK_POINTER_REGNUM): Change all uses to
__LIBGCC_STACK_POINTER_REGNUM__.
* config/rs6000/darwin-fallback.c (STACK_POINTER_REGNUM): Change
use to __LIBGCC_STACK_POINTER_REGNUM__.
* config/rs6000/linux-unwind.h (STACK_POINTER_REGNUM): Change all
uses to __LIBGCC_STACK_POINTER_REGNUM__.
* config/sparc/linux-unwind.h (DWARF_FRAME_REGISTERS): Change use
to __LIBGCC_DWARF_FRAME_REGISTERS__.
* config/sparc/sol2-unwind.h (DWARF_FRAME_REGISTERS): Change use
to __LIBGCC_DWARF_FRAME_REGISTERS__.
* config/tilepro/linux-unwind.h (STACK_POINTER_REGNUM): Change use
to __LIBGCC_STACK_POINTER_REGNUM__.
* config/xtensa/unwind-dw2-xtensa.h (DWARF_FRAME_REGISTERS):
Remove conditional definition.
* crtstuff.c (TEXT_SECTION_ASM_OP): Change all uses to
__LIBGCC_TEXT_SECTION_ASM_OP__.
(EH_FRAME_SECTION_NAME): Change all uses to
__LIBGCC_EH_FRAME_SECTION_NAME__.
(EH_TABLES_CAN_BE_READ_ONLY): Change all uses to
__LIBGCC_EH_TABLES_CAN_BE_READ_ONLY__.
(CTORS_SECTION_ASM_OP): Change all uses to
__LIBGCC_CTORS_SECTION_ASM_OP__.
(DTORS_SECTION_ASM_OP): Change all uses to
__LIBGCC_DTORS_SECTION_ASM_OP__.
(JCR_SECTION_NAME): Change all uses to
__LIBGCC_JCR_SECTION_NAME__.
(INIT_SECTION_ASM_OP): Change all uses to
__LIBGCC_INIT_SECTION_ASM_OP__.
(INIT_ARRAY_SECTION_ASM_OP): Change all uses to
__LIBGCC_INIT_ARRAY_SECTION_ASM_OP__.
* generic-morestack.c (STACK_GROWS_DOWNWARD): Change all uses to
__LIBGCC_STACK_GROWS_DOWNWARD__.
* libgcc2.c (INIT_SECTION_ASM_OP): Change all uses to
__LIBGCC_INIT_SECTION_ASM_OP__.
(INIT_ARRAY_SECTION_ASM_OP): Change all uses to
__LIBGCC_INIT_ARRAY_SECTION_ASM_OP__.
(EH_FRAME_SECTION_NAME): Change all uses to
__LIBGCC_EH_FRAME_SECTION_NAME__.
* libgcov-profiler.c (VTABLE_USES_DESCRIPTORS): Remove conditional
definitions. Change all uses to
__LIBGCC_VTABLE_USES_DESCRIPTORS__.
* unwind-dw2.c (STACK_GROWS_DOWNWARD): Change all uses to
__LIBGCC_STACK_GROWS_DOWNWARD__.
(DWARF_FRAME_REGISTERS): Change all uses to
__LIBGCC_DWARF_FRAME_REGISTERS__.
(EH_RETURN_STACKADJ_RTX): Change all uses to
__LIBGCC_EH_RETURN_STACKADJ_RTX__.
* unwind-dw2.h (DWARF_FRAME_REGISTERS): Remove conditional
definition. Change use to __LIBGCC_DWARF_FRAME_REGISTERS__.
* unwind-sjlj.c (DONT_USE_BUILTIN_SETJMP): Change all uses to
__LIBGCC_DONT_USE_BUILTIN_SETJMP__.
(JMP_BUF_SIZE): Change use to __LIBGCC_JMP_BUF_SIZE__.
From-SVN: r214954
PR tree-optimization/53265
* common.opt (Waggressive-loop-optimizations): New option.
* tree-ssa-loop-niter.c: Include tree-pass.h.
(do_warn_aggressive_loop_optimizations): New function.
(record_estimate): Call it. Don't add !is_exit bounds to loop->bounds
if number_of_latch_executions returned constant.
(estimate_numbers_of_iterations_loop): Call number_of_latch_executions
early. If number_of_latch_executions returned constant, set
nb_iterations_upper_bound back to it.
* cfgloop.h (struct loop): Add warned_aggressive_loop_optimizations
field.
* Makefile.in (tree-ssa-loop-niter.o): Depend on $(TREE_PASS_H).
* doc/invoke.texi (-Wno-aggressive-loop-optimizations): Document.
* gcc.dg/pr53265.c: New test.
* gcc.dg/torture/pr49518.c: Add -Wno-aggressive-loop-optimizations
to dg-options.
* g++.dg/opt/longbranch2.C (EBCOTLut): Double sizes of a2 and a3
arrays.
* gcc.dg/tree-ssa/cunroll-10.c (main): Rename to foo. Add argument
n, use it as high bound instead of 4.
* unwind-dw2.c (execute_cfa_program): Avoid
-Waggressive-array-optimizations warnings for DW_CFA_GNU_window_save
on targets with DWARF_FRAME_REGISTERS < 32.
* testsuite/libmudflap.c/fail37-frag.c: Add optimization barrier.
From-SVN: r196650
