This patch does not modify the functionality of the compiler; it avoids
generating non-required alignment representation clauses for dispatch
tables.

2019-09-18  Javier Miranda  <miranda@adacore.com>

gcc/ada/

	* exp_disp.adb (Make_DT, Make_Secondary_DT): Remove generation
	of alignment representation clause for the following tables:
	Predef_Prims, Iface_DT, TSD, ITable, DT.

From-SVN: r275853

In sem_eval.adb, we have an assertion that the type of a "null" literal
is an access type. It turns out that this assertion can fail when
processing an illegal program, e.g. one that contains something like
"Integer'(null)".  This leads to differences in the compiler's generated
output for such tests depending on whether assertions are/aren't
enabled; in particular, the "compilation abandoned due to previous
error" message generated in Comperr.Compiler_Abort. In order to avoid
these differences, we change the assertion so that it does not fail if
errors have already been posted on the given node.

2019-09-18  Steve Baird  <baird@adacore.com>

gcc/ada/

	* sem_eval.adb (Expr_Value): Do not fail "the type of a null
	literal must be an access type" assertion if errors have already
	been posted on the given node.

From-SVN: r275852

Routine Get_Homonym_Number always returns a positive number. This is
explained in its comment and is evident from its body. No test attached,
because semantics is unaffected.

2019-09-18  Piotr Trojanek  <trojanek@adacore.com>

gcc/ada/

	* exp_dbug.ads, exp_dbug.adb (Get_Homonym_Number): Refine type
	from Nat to Pos.
	* sem_util.adb (Add_Homonym_Suffix): Refine type of a local
	variable.

From-SVN: r275851

GNATprove was using the qualification of names for entities with local
homonyms in the same scope, requiring the use of a suffix to
differentiate them. This caused problems for correctly identifying
primitive equality operators. This case is now handled like the rest of
entities in GNATprove, by instead updating Unique_Name to append the
suffix on-the-fly where needed.

There is no impact on compilation and hence no test.

2019-09-18  Yannick Moy  <moy@adacore.com>

gcc/ada/

	* exp_dbug.adb (Append_Homonym_Number): Use new function
	Get_Homonym_Number.
	(Get_Homonym_Number): New function to return the homonym number.
	(Qualify_Entity_Name): Remove special case for GNATprove.
	* exp_dbug.ads (Get_Homonym_Number): Make the new function
	public for use in GNATprove.
	* frontend.adb (Frontend): Do not qualify names in GNATprove
	mode.
	* sem_util.adb (Unique_Name): Append homonym suffix where needed
	for entities which have local homonyms in the same scope.

From-SVN: r275850

Previous change in that procedure to handle overflow issues during
scanning removed the special handling for trailing zeros in the decimal
part. Beside the absence of overflow during scanning the special
handling of these zeros is still necessary.

2019-09-18  Nicolas Roche  <roche@adacore.com>

gcc/ada/

	* libgnat/s-valrea.adb (Scan_Integral_Digits): New procedure.
	(Scan_Decimal_Digits): New procedure.
	(As_Digit): New function.
	(Scan_Real): Use Scan_Integral_Digits and Scan_Decimal_Digits.

gcc/testsuite/

	* gnat.dg/float_value2.adb: New testcase.

From-SVN: r275849

Create a separate routine in Exp_Util for deciding the value of the
Constrained attribute when it is statically known. This routine is used
in Exp_Attr and will be reused in the backend of GNATprove.

There is no impact on compilation and hence no test.

2019-09-18  Claire Dross  <dross@adacore.com>

gcc/ada/

	* exp_attr.adb (Expand_N_Attribute_Reference): Call routine from
	Exp_Util to know the value of the Constrained attribute in the
	static case.
	* exp_spark.adb (Expand_SPARK_N_Attribute_Reference): Make
	implicit dereferences inside the Constrained attribute explicit.
	* exp_util.ads, exp_util.adb
	(Attribute_Constrained_Static_Value): New routine to compute the
	value of a statically known reference to the Constrained
	attribute.

From-SVN: r275848

Call to Expect for a dead process results in SIGBUS signal on Linux
systems. Process_Died exception is raised in this case now.

2019-09-18  Vadim Godunko  <godunko@adacore.com>

gcc/ada/

	* libgnat/g-expect.adb (Expect_Internal): Don't include invalid
	file descriptors into the set of file descriptors for Poll.
	Raise Process_Died exception when computed set of file
	descriptors to monitor is empty.

gcc/testsuite/

	* gnat.dg/expect4.adb: New testcase.

From-SVN: r275847

This fixes the wrong errno for rename when the file is not existing on a
dosFs. In the end it makes Ada.Directories.Rename raising the right
exception in the case we are trying to move a file in a non existing
directory.

2019-09-18  Frederic Konrad  <konrad@adacore.com>

gcc/ada/

	* adaint.c: Include dosFsLib.h and vwModNum.h for VxWorks 6.
	(__gnat_rename): Map S_dosFsLib_FILE_NOT_FOUND to ENOENT.

From-SVN: r275846

In some cases where the size computation for an object declaration will
unconditionally overflow, the FE generates code to raise Storage_Error
at the point of the object declaration (and may generate an associated
warning). Don't do this if the object declaration is an ignored (i.e.,
disabled) ghost declaration.

2019-09-18  Steve Baird  <baird@adacore.com>

gcc/ada/

	* freeze.adb (Freeze_Object_Declaration): Do not call
	Check_Large_Modular_Array when the object declaration being
	frozen is an ignored ghost entity.

gcc/testsuite/

	* gnat.dg/ghost7.adb, gnat.dg/ghost7.ads: New testcase.

From-SVN: r275845

An error message mentions "gnamake", where it meant to mention
"gnatmake".

2019-09-18  Tom Tromey  <tromey@adacore.com>

gcc/ada/

	* make.adb (Initialize): Fix typo.

From-SVN: r275844

The dwActiveProcessorMask field in a SYSTEM_INFO structure on Windows
should be DWORD_PTR, an integer the size of a pointer.

In s-win32, it is currently declared as DWORD. This happens to work on
32bit hosts and is wrong on 64bit hosts, causing mishaps in accesses to
this component and all the following ones.

The proposed correction adds a definition for DWORD_PTR and uses it for
dwActiveProcessorMask in System.Win32.SYSTEM_INFO.

2019-09-18  Olivier Hainque  <hainque@adacore.com>

gcc/ada/

	* libgnat/s-win32.ads (DWORD_PTR): New type, pointer size
	unsigned int.
	(SYSTEM_INFO): Use it for dwActiveProcessorMask.

gcc/testsuite/

	* gnat.dg/system_info1.adb: New testcase.

From-SVN: r275843

2019-09-18  Arnaud Charlet  <charlet@adacore.com>

gcc/ada/

	* doc/gnat_rm/implementation_defined_pragmas.rst: Improve doc on
	Warning_As_Error.
	* gnat_rm.texi: Regenerate.

From-SVN: r275842

2019-09-18  Arnaud Charlet  <charlet@adacore.com>

gcc/ada/

	* doc/gnat_rm/implementation_defined_characteristics.rst,
	doc/gnat_rm/implementation_defined_pragmas.rst,
	doc/gnat_rm/implementation_of_specific_ada_features.rst: Remove
	remaining references to VMS support
	* gnat_rm.texi: Regenerate.

From-SVN: r275841

2019-09-18  Arnaud Charlet  <charlet@adacore.com>

gcc/ada/

	* libgnat/s-stausa.adb: Fix a typo

From-SVN: r275840

In function Copy in Ada.Containers.Bounded_Ordered_Sets and other
bounded containers packages, remove a possible use of an uninitialized
variable. This was not a bug, because the uninitialized variable could
be used only if checks are suppressed, and the checks would have failed,
leading to erroneous execution.

However, it seems more robust this way, and is probably equally
efficient, and avoids a warning that is given if checks are suppressed,
and the -Wall switch is given, and optimization is turned on.

2019-09-18  Bob Duff  <duff@adacore.com>

gcc/ada/

	* libgnat/a-cbhama.adb, libgnat/a-cbhase.adb,
	libgnat/a-cbmutr.adb, libgnat/a-cborma.adb,
	libgnat/a-cborse.adb, libgnat/a-cobove.adb (Copy): Avoid reading
	the uninitialized variable C in the Checks = False case. Change
	variable to be a constant.

gcc/testsuite/

	* gnat.dg/containers1.adb, gnat.dg/containers1.ads: New
	testcase.

From-SVN: r275839

Rename global constants from I to J. No functional changes.

2019-09-18  Claire Dross  <dross@adacore.com>

gcc/ada/

	* libgnat/a-cofuma.adb (Remove, Elements_Equal_Except,
	Keys_Included, Keys_Included_Except): Rename loop indexes and
	global constants from I to J.

From-SVN: r275838

2019-09-18  Arnaud Charlet  <charlet@adacore.com>

gcc/ada/

	* exp_unst.adb (Unnest_Subprograms): Refine previous change.

From-SVN: r275837

gcc/testsuite/gcc.target/i386/pr82361-[12].c check whether we
can optimise away a 32-to-64-bit zero extension of a 32-bit
division or modulus result.  Currently this fails for the modulus
part of f1 and f2 in pr82361-1.c:

/* FIXME: We are still not able to optimize the modulo in f1/f2, only manage
   one.  */
/* { dg-final { scan-assembler-times "movl\t%edx" 2 } } */

pr82361-2.c instead expects no failures:

/* Ditto %edx to %rdx zero extensions.  */
/* { dg-final { scan-assembler-not "movl\t%edx, %edx" } } */

But we actually get the same zero-extensions for f1 and f2 in pr82361-2.c.
The reason they don't trigger a failure is that the RA allocates the
asm input for "d" to %rdi rather than %rdx, so we have:

	movl	%rdx, %rdi

instead of:

	movl	%rdx, %rdx

For the tests to work as expected, I think they have to force "c" and
"d" to be %rax and %rdx respectively.  We then see the same failure in
pr82361-2.c as for pr82361-1.c (but doubled, due to the 8-bit division
path).

2019-09-18  Richard Sandiford  <richard.sandiford@arm.com>

gcc/testsuite/
	* gcc.target/i386/pr82361-1.c (f1, f2, f3, f4, f5, f6): Force
	"c" to be in %rax and "d" to be in %rdx.
	* gcc.target/i386/pr82361-2.c: Expect 4 instances of "movl\t%edx".

From-SVN: r275836

From-SVN: r275833

    
    This only matters on systems that pass a struct with a single pointer
    field differently than passing a single pointer.  I noticed it on
    32-bit PPC, where the reflect package TestDirectIfaceMethod failed.
    
    Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/195878

From-SVN: r275814

	PR go/91781
    reflect: promote integer closure return to full word
    
    The libffi library expects an integer return type to be promoted to a
    full word.  Implement that when returning from a closure written in Go.
    This only matters on big-endian systems when returning an integer smaller
    than the pointer size, which is why we didn't notice it until now.
    
    Fixes https://gcc.gnu.org/PR91781.
    
    Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/195858

From-SVN: r275813

    
    The function was always intended to be internal-only, but was exported
    so that C code could call it. Now that have go:linkname for that, use it.
    
    Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/195857

From-SVN: r275809

Since no_insn patterns expand to no instructions, they shouldn't
count against the issue rate, just like USEs and CLOBBERs don't.

2019-09-17  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* config/aarch64/aarch64.c (aarch64_sched_variable_issue): New
	function.
	(TARGET_SCHED_VARIABLE_ISSUE): New macro.
	* config/arm/arm.c (arm_sched_variable_issue): New function.
	(TARGET_SCHED_VARIABLE_ISSUE): New macro.

From-SVN: r275808

no_insn is documented as:

  an insn which does not represent an instruction in the final output,
  thus having no impact on scheduling.

and is used in that way by the arm port (e.g. for define_insns that
expand to comments).  However, most scheduling descriptions instead
assigned units to no_insn patterns, in some cases treating them as more
expensive than a plain move.

This patch removes the no_insn handling from individual scheduling
descriptions and uses a common define_insn_reservation for all CPUs.

2019-09-17  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* config/arm/types.md (no_reservation): New reservation.
	* config/aarch64/falkor.md (falkor_other_0_nothing): Don't handle
	no_insn here.
	* config/aarch64/saphira.md (saphira_other_0_nothing): Likewise.
	* config/aarch64/thunderx2t99.md (thunderx2t99_nothing): Likewise.
	* config/aarch64/tsv110.md (tsv110_alu): Likewise.
	* config/arm/arm1020e.md (1020alu_op): Likewise.
	* config/arm/arm1026ejs.md (alu_op): Likewise.
	* config/arm/arm1136jfs.md (11_alu_op): Likewise.
	* config/arm/arm926ejs.md (9_alu_op): Likewise.
	* config/arm/cortex-a15.md (cortex_a15_alu): Likewise.
	* config/arm/cortex-a17.md (cortex_a17_alu): Likewise.
	* config/arm/cortex-a5.md (cortex_a5_alu): Likewise.
	* config/arm/cortex-a53.md (cortex_a53_alu): Likewise.
	* config/arm/cortex-a57.md (cortex_a57_alu): Likewise.
	* config/arm/cortex-a7.md (cortex_a7_alu_shift): Likewise.
	* config/arm/cortex-a8.md (cortex_a8_alu): Likewise.
	* config/arm/cortex-a9.md (cortex_a9_dp): Likewise.
	* config/arm/cortex-m4.md (cortex_m4_alu): Likewise.
	* config/arm/cortex-m7.md (cortex_m7_alu_simple): Likewise.
	* config/arm/cortex-r4.md (cortex_r4_alu_shift_reg): Likewise.
	* config/arm/fa526.md (526_alu_op): Likewise.
	* config/arm/fa606te.md (606te_alu_op): Likewise.
	* config/arm/fa626te.md (626te_alu_op): Likewise.
	* config/arm/fa726te.md (726te_alu_op): Likewise.
	* config/arm/xgene1.md (xgene1_nop): Likewise.

From-SVN: r275807

*thumb1_tablejump had type "no_insn", which doesn't seems to correspond
to its documented use:

  an insn which does not represent an instruction in the final output,
  thus having no impact on scheduling.

Indirect jumps use the same instruction and have type "branch",
so the patch uses "branch" here too.

2019-09-17  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* config/arm/thumb1.md (*thumb1_tablejump): Change type from
	"no_insn" to "branch".

From-SVN: r275806

2019-09-17  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* array-traits.h (array_traits<T[N]>::size): Remove parameter name.

From-SVN: r275805

2019-09-17  Richard Biener  <rguenther@suse.de>

	PR debug/91772
	* dwarf2out.c (dwarf2out_late_global_decl): If early dwarf
	was missing generate locations only once.

From-SVN: r275804

Since FDPIC currently supports arm and thumb-2 modes only, these tests
fail because they enforce an architecture version that doesn't match
these restrictions.

This patch introduces new values for the arm_arch effective-target
(v4t_thumb, v5t_thumb, v5te_thumb, v6_thumb, v6k_thumb, v6z_thumb) as
needed, and adds them to the relevant tests.  In addition, it adds
v4t_arm, v5t_arm, v5te_arm, v6_arm, v6k_arm and v6z_arm to avoid
skipping some tests when GCC is configured to generate Thumb code by
default.

It also adds the corresponding non-thumb effective-target to the tests
that were missing it.

The existing v4t, v5t, v5te, v6 v6k and v6z effective-targets now force
-mfloat-abi=softfp since these thumb-1 targets do not support
hard-float anyway.

Finally, the patch removes the special case to detect the presence of
-marm in the flags, since it makes atomic_loaddi tests unsupported:
since the flags in question also include -march, the combination is
supported, while -marm alone is not if GCC is configured to target an
M-profile CPU.

2019-19-17  Christophe Lyon  <christophe.lyon@st.com>

	* lib/target-supports.exp
	(check_effective_target_arm_arch_FUNC_ok): Add v4t_arm, v4t_thumb,
	v5t_arm, v5t_thumb, v5te_arm, v5te_thumb, v6_arm, v6_thumb,
	v6k_arm, v6k_thumb, v6z_arm, v6z_thumb.
	Add -mfloat-abi=softfp to v4t, v5t, v5te, v6, v6k, v6z.
	Remove early exit for -marm.
	* gcc.target/arm/armv6-unaligned-load-ice.c: Add arm_arch
	effective-target.
	* gcc.target/arm/attr-unaligned-load-ice.c: Likewise.
	* gcc.target/arm/ftest-armv4-arm.c: Likewise.
	* gcc.target/arm/ftest-armv4t-arm.c: Likewise.
	* gcc.target/arm/ftest-armv4t-thumb.c: Likewise.
	* gcc.target/arm/ftest-armv5t-arm.c: Likewise.
	* gcc.target/arm/ftest-armv5t-thumb.c: Likewise.
	* gcc.target/arm/ftest-armv5te-arm.c: Likewise.
	* gcc.target/arm/ftest-armv5te-thumb.c: Likewise.
	* gcc.target/arm/ftest-armv6-arm.c: Likewise.
	* gcc.target/arm/ftest-armv6-thumb.c: Likewise.
	* gcc.target/arm/ftest-armv6k-arm.c: Likewise.
	* gcc.target/arm/ftest-armv6k-thumb.c: Likewise.
	* gcc.target/arm/ftest-armv6m-thumb.c: Likewise.
	* gcc.target/arm/ftest-armv6t2-arm.c: Likewise.
	* gcc.target/arm/ftest-armv6t2-thumb.c: Likewise.
	* gcc.target/arm/ftest-armv6z-arm.c: Likewise.
	* gcc.target/arm/ftest-armv6z-thumb.c: Likewise.
	* gcc.target/arm/g2.c: Likewise.
	* gcc.target/arm/macro_defs1.c: Likewise.
	* gcc.target/arm/pr59858.c: Likewise.
	* gcc.target/arm/pr65647-2.c: Likewise.
	* gcc.target/arm/pr79058.c: Likewise.
	* gcc.target/arm/pr83712.c: Likewise.
	* gcc.target/arm/pragma_arch_switch_2.c: Likewise.
	* gcc.target/arm/scd42-1.c: Likewise.
	* gcc.target/arm/scd42-2.c: Likewise.
	* gcc.target/arm/scd42-3.c: Likewise.
	* gcc.c-torture/compile/pr82096.c: Fix arm_arch effective-target.
	* gcc.target/arm/attr_arm-err.c: Likewise.
	* gcc.target/arm/di-longlong64-sync-withldrexd.c: Likewise.

From-SVN: r275803

2019-09-17  Feng Xue  <fxue@os.amperecomputing.com>

        PR ipa/91089
        * doc/invoke.texi (ipa-max-switch-predicate-bounds): Document new
        option.
        * params.def (PARAM_IPA_MAX_SWITCH_PREDICATE_BOUNDS): New.
        * ipa-fnsummary.c (set_switch_stmt_execution_predicate): Add predicate
        for switch default case using range analysis information.

2019-09-17  Feng Xue  <fxue@os.amperecomputing.com>

        PR ipa/91089
        * gcc.dg/ipa/pr91089.c: New test.

From-SVN: r275802

2019-09-17  Paul Thomas  <pault@gcc.gnu.org>

	PR fortran/91588
	* expr.c (check_inquiry): Remove extended component refs by
	using symbol pointers. If a function argument is an associate
	variable with a constant target, copy the target expression in
	place of the argument expression. Check that the charlen is not
	NULL before using the string length.
	(gfc_check_assign): Remove extraneous space.

2019-09-17  Paul Thomas  <pault@gcc.gnu.org>

	PR fortran/91588
	* gfortran.dg/associate_49.f90 : New test.

From-SVN: r275800

2019-09-16  Christophe Lyon  <christophe.lyon@linaro.org>

	PR target/91749
	* config/arm/arm.c (arm_valid_target_attribute_rec): Make sure the
	mode attributed is supported by FDPIC.

From-SVN: r275799

re PR tree-optimization/91790 (ICE: verify_ssa failed (error: definition in block 2 follows the use))

2019-09-17  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/91790
	* tree-vect-stmts.c (vectorizable_load): For BB vectorization
	use the correct DR for setting up realignment.

From-SVN: r275798

A primitive for removing a mapping from a functional map has been added.

2019-09-17  Claire Dross  <dross@adacore.com>

gcc/ada/

	* libgnat/a-cofuma.ads, libgnat/a-cofuma.adb (Remove): New
	function which returns a copy of the input container without a
	given mapping.

From-SVN: r275797

Fixed-point multiplication, division and conversion may lead to calling
the function Double_Divide in s-arit64 runtime unit. In the special case
where arguments have the special values X = -2**63 and the absolute
value of the product of its other arguments Y*Z = 2**64, the rounded
value should be either -1 or 1, but currently Double_Divide returns a
quotient of 0.

Rounding only applies when Round attribute is called on the arithmetic
operation for a decimal fixed-point result, or the result type is
integer.

This fixes correctly applies rounding away from 0 in that special case.

2019-09-17  Yannick Moy  <moy@adacore.com>

gcc/ada/

	* libgnat/s-arit64.adb (Double_Divide): Correctly handle the
	special case when rounding.

gcc/testsuite/

	* gnat.dg/fixedpnt7.adb: New testcase.

From-SVN: r275796

The frontend silently skips propagating attributes Has_Predicates and
Predicate function to the internally built cloned subtype. This change
does not affect the functionality of the compiler; it leaves more clean
the decoration of internal entities.

2019-09-17  Javier Miranda  <miranda@adacore.com>

gcc/ada/

	* sem_ch3.adb (Complete_Private_Subtype): Propagate attributes
	Has_Attributes and Predicate_Function to the cloned subtype.

From-SVN: r275795

This fixes a recent regression introduced in the machinery giving style
warnings: the -gnatyN switch no longer cancels an earlier -gnaty switch
for separate compilation units.

Running this command:

  gcc -c slib.adb -gnatyaAbcefhiIklmM25OnprStux -gnatyN

On the following sources:

package Slib is
   procedure I_Am_Short;
end Slib;

with Ada.Text_IO; use Ada.Text_IO;

package body Slib is
   --  have a long line here as well.
   procedure                I_Am_Short is               separate;
end Slib;

separate (Slib)

procedure I_Am_Short is
begin
    Put_Line (".......................................................");
end I_Am_Short;

Should execute silently.

2019-09-17  Eric Botcazou  <ebotcazou@adacore.com>

gcc/ada/

	* sem.adb (Do_Analyze): Save Style_Check_Max_Line_Length on
	entry and restore it on exit instead of recomputing it.

From-SVN: r275794

The character type comment in exp_dbug.ads documented the QU and QW
encodings, but did not document the plain "Qc" encoding, where 'c' is
the character itself.  This patch updates the comment to follow the
implementation.

2019-09-17  Tom Tromey  <tromey@adacore.com>

gcc/ada/

	* exp_dbug.ads: Update character type comment.

From-SVN: r275793

Multiple comments in functions Double_Divide and Scaled_Divide were
incorrect. Now fixed.

Also change the expression (if Zhi /= 0 then Ylo * Zhi else 0) to the
simpler equivalent (Ylo * Zhi) in Double_Divide.

Also add a comment explaining why the implementation of Algorithm D for
multiple-precision division from the 2nd Edition of The Art of Computer
Programming does not suffer from two bugs discovered on that version.

There is no impact on execution, hence no test.

2019-09-17  Yannick Moy  <moy@adacore.com>

gcc/ada/

	* libgnat/s-arit64.adb (Double_Divide): Simplify needlessly
	complex computation. Fix comments.
	(Scaled_Divide): Fix comments. Explain why implementation does
	not suffer from bugs in Algorithm D from 2nd Edition of TAOCP.

From-SVN: r275792

Function Scaled_Divide in s-arith runtime unit computes the combined
multiplication and division of its arguments ((X*Y) / Z). In a very
special case where the quotient computed before rounding is 2**64-1,
then rounding may lead to undesirable wrap-around, leading to a computed
quotient of 0 instead of raising Constraint_Error as expected.

This function is only called in the runtime for arithmetic operations
involving fixed-point types. Rounding is performed only when the target
type is of a decimal fixed-point type, and the attribute 'Round of the
type is used to round the result of the arithmetic operation.

This fix correctly raises Constraint_Error in this special case.

2019-09-17  Yannick Moy  <moy@adacore.com>

gcc/ada/

	* libgnat/s-arit64.adb (Scaled_Divide): Add protection against
	undesirable wrap-around.

gcc/testsuite/

	* gnat.dg/multfixed.adb: New testcase.

From-SVN: r275791

Function Double_Divide computes the division of its parameters
(X / (Y*Z)) in a way that avoids overflows on signed integers, except in
two specific cases, when X = -2**63, abs(Y) = abs(Z) = 1 (leading to an
overflow in -To_Int(Qu)) and when X = -2**63 and Y*Z is large enough
that Qu=0 and so the remainder Ru=2**63 (leading to an overflow in
-To_Int(Ru)), for example with Y = Z = 2**32-1.

This fix avoids the overflow by applying "-" on the unsigned value
before the conversion to signed integer.

The issue cannot manifest as an overflow check failure in our runtime,
as overflow checks are suppressed by using pragma Suppress at the start
of the file. Assuming a machine implements wraparound semantics here,
the result was correct even with the suppressed overflow.

As a result, there can be no test showing the difference.

2019-09-17  Yannick Moy  <moy@adacore.com>

gcc/ada/

	* libgnat/s-arit64.adb (Double_Divide): Fix two possible
	overflows.

From-SVN: r275790