[Bug rtl-optimization/44484] New: [4.6 regression] revision 160260 caused sparc64 testsuite failures

[Bug rtl-optimization/44484] New: [4.6 regression] revision 160260 caused sparc64 testsuite failures

[mikpe at it dot uu dot se]

Between gcc-4.6-20100529 and gcc-4.6-20100605 a number of new testsuite FAILs
appeared on sparc64-linux:

                === gfortran tests ===

FAIL: gfortran.fortran-torture/execute/forall_7.f90 execution,  -O2
-fomit-frame-pointer -finline-functions -funroll-loops 
FAIL: gfortran.fortran-torture/execute/forall_7.f90 execution,  -O3 -g 

                === libgomp tests ===


FAIL: libgomp.c/nestedfn-3.c (test for excess errors)
WARNING: libgomp.c/nestedfn-3.c compilation failed to produce executable
FAIL: libgomp.c/nestedfn-4.c (test for excess errors)
WARNING: libgomp.c/nestedfn-4.c compilation failed to produce executable
FAIL: libgomp.c/task-2.c (test for excess errors)
WARNING: libgomp.c/task-2.c compilation failed to produce executable
FAIL: libgomp.fortran/omp_atomic1.f90  -O1  (test for excess errors)
WARNING: libgomp.fortran/omp_atomic1.f90  -O1  compilation failed to produce
executable
FAIL: libgomp.fortran/omp_atomic1.f90  -O2  (test for excess errors)
WARNING: libgomp.fortran/omp_atomic1.f90  -O2  compilation failed to produce
executable
FAIL: libgomp.fortran/omp_atomic1.f90  -O3 -fomit-frame-pointer  (test for
excess errors)
WARNING: libgomp.fortran/omp_atomic1.f90  -O3 -fomit-frame-pointer  compilation
failed to produce executable
FAIL: libgomp.fortran/omp_atomic1.f90  -O3 -fomit-frame-pointer -funroll-loops 
(test for excess errors)
WARNING: libgomp.fortran/omp_atomic1.f90  -O3 -fomit-frame-pointer
-funroll-loops  compilation failed to produce executable
FAIL: libgomp.fortran/omp_atomic1.f90  -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions  (test for excess errors)
WARNING: libgomp.fortran/omp_atomic1.f90  -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions  compilation failed to produce executable
FAIL: libgomp.fortran/omp_atomic1.f90  -O3 -g  (test for excess errors)
WARNING: libgomp.fortran/omp_atomic1.f90  -O3 -g  compilation failed to produce
executable
FAIL: libgomp.fortran/omp_atomic1.f90  -Os  (test for excess errors)
WARNING: libgomp.fortran/omp_atomic1.f90  -Os  compilation failed to produce
executable
FAIL: libgomp.fortran/omp_atomic2.f90  -O1  (test for excess errors)
WARNING: libgomp.fortran/omp_atomic2.f90  -O1  compilation failed to produce
executable
FAIL: libgomp.fortran/omp_atomic2.f90  -O2  (test for excess errors)
WARNING: libgomp.fortran/omp_atomic2.f90  -O2  compilation failed to produce
executable
FAIL: libgomp.fortran/omp_atomic2.f90  -O3 -fomit-frame-pointer  (test for
excess errors)
WARNING: libgomp.fortran/omp_atomic2.f90  -O3 -fomit-frame-pointer  compilation
failed to produce executable
FAIL: libgomp.fortran/omp_atomic2.f90  -O3 -fomit-frame-pointer -funroll-loops 
(test for excess errors)
WARNING: libgomp.fortran/omp_atomic2.f90  -O3 -fomit-frame-pointer
-funroll-loops  compilation failed to produce executable
FAIL: libgomp.fortran/omp_atomic2.f90  -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions  (test for excess errors)
WARNING: libgomp.fortran/omp_atomic2.f90  -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions  compilation failed to produce executable
FAIL: libgomp.fortran/omp_atomic2.f90  -O3 -g  (test for excess errors)
WARNING: libgomp.fortran/omp_atomic2.f90  -O3 -g  compilation failed to produce
executable
FAIL: libgomp.fortran/omp_atomic2.f90  -Os  (test for excess errors)
WARNING: libgomp.fortran/omp_atomic2.f90  -Os  compilation failed to produce
executable

I've traced this to r160260 (fix PR39871, PR40615, PR42500, PR42502). Some
intermediate revisions cause bootstrap breakage making a bisection difficult,
but reverting r160260 from gcc-4.6-20100605 eliminates the FAILs above.

Although most FAILs are for Fortran, there are also three C-only libgomp tests
that now FAIL.

Compare also

http://gcc.gnu.org/ml/gcc-testresults/2010-06/msg00316.html (r160217, libgomp)
http://gcc.gnu.org/ml/gcc-testresults/2010-05/msg02923.html (r160038, fortran
and libgomp)

with

http://gcc.gnu.org/ml/gcc-testresults/2010-06/msg00454.html (r160287, libgomp)
http://gcc.gnu.org/ml/gcc-testresults/2010-06/msg00590.html (r160330, fortran
and libgomp)

I'll check tomorrow if any of these are reproducible with a cross-compiler.


-- 
           Summary: [4.6 regression] revision 160260 caused sparc64
                    testsuite failures
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: mikpe at it dot uu dot se
 GCC build triplet: sparc64-unknown-linux-gnu
  GCC host triplet: sparc64-unknown-linux-gnu
GCC target triplet: sparc64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44484

[Bug rtl-optimization/44484] [4.6 regression] revision 160260 caused sparc64 testsuite failures

[rguenth at gcc dot gnu dot org]

-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.6.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44484

[Bug rtl-optimization/44484] [4.6 regression] revision 160260 caused sparc64 testsuite failures

[mikpe at it dot uu dot se]

------- Comment #1 from mikpe at it dot uu dot se  2010-06-11 21:07 -------
Created an attachment (id=20896)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20896&action=view)
task-2.c test case from libgomp's test suite


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44484

[Bug rtl-optimization/44484] [4.6 regression] revision 160260 caused sparc64 testsuite failures

[mikpe at it dot uu dot se]

------- Comment #2 from mikpe at it dot uu dot se  2010-06-11 21:09 -------
Created an attachment (id=20897)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20897&action=view)
broken -S output from gcc-4.6-20100605


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44484

[Bug rtl-optimization/44484] [4.6 regression] revision 160260 caused sparc64 testsuite failures

[mikpe at it dot uu dot se]

------- Comment #3 from mikpe at it dot uu dot se  2010-06-11 21:10 -------
Created an attachment (id=20898)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20898&action=view)
working -S output from gcc-4.6-20100605 with r160260 reverted


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44484

[Bug rtl-optimization/44484] [4.6 regression] revision 160260 caused sparc64 testsuite failures

[mikpe at it dot uu dot se]

------- Comment #4 from mikpe at it dot uu dot se  2010-06-11 21:27 -------
The bug is easily observed with a cross to sparc64-linux, using e.g. the
task-2.c test case in libgomp's libgomp.c test suite.

Diffing the -S output of 4.6-20100605 vanilla (bad) with the same where r160260
has been reverted (ok), we see:

--- task-2.s-bad        2010-06-11 22:45:02.000000000 +0200
+++ task-2.s-ok 2010-06-11 22:51:56.000000000 +0200
@@ -5,20 +5,21 @@
        .proc   020
 f2._omp_fn.1:
        .register       %g2, #scratch
+       .register       %g3, #scratch
        add     %sp, -192, %sp
        lduw    [%o0+12], %g1
        st      %g1, [%sp+2235]
        lduw    [%o0+8], %g2
        cmp     %g2, 10
        bne,pt  %icc, .LL7
-        nop
+        add    %sp, 2235, %g3
        ba,pt   %xcc, .LL9
         sub    %sp, -192, %sp
 .LL5:
 .LL7:
        membar  15
        add     %g1, 1, %g2
-       cas     [%sp+2235], %g1, %g2
+       cas     [%g3], %g1, %g2
        cmp     %g1, %g2
        bne,pt  %icc, .LL5
         mov    %g2, %g1

So what r160260 did was to replace [%g3] in the cas instruction with
[%sp+2235], which doesn't work because cas cannot use [reg+offset] addressing
modes, it only accepts [reg] addressing modes.

Attempting to assemble these files confirms:
> sparc64-unknown-linux-as task-2.s-ok
> sparc64-unknown-linux-as task-2.s-bad 
task-2.s-bad: Assembler messages:
task-2.s-bad:21: Error: Illegal operands
task-2.s-bad:48: Error: Illegal operands

To compile task-2.c I used sparc64-unknown-linux-gcc -mcpu=v9
-fmessage-length=0 -fopenmp -O2 -S task-2.c (the -mcpu=v9 may be redundant, but
that's what the libgomp test suite did on the actual sparc64 box).

My sparc64 cross is configured simply with --target=sparc64-unknown-linux
--enable-languages=c.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44484

[Bug rtl-optimization/44484] [4.6 regression] revision 160260 caused sparc64 testsuite failures

[ebotcazou at gcc dot gnu dot org]

------- Comment #6 from ebotcazou at gcc dot gnu dot org  2010-06-11 21:30 -------
Investigating.


-- 

ebotcazou at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |ebotcazou at gcc dot gnu dot
                   |dot org                     |org
             Status|UNCONFIRMED                 |ASSIGNED
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2010-06-11 21:30:34
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44484

[Bug rtl-optimization/44484] [4.6 regression] revision 160260 caused sparc64 testsuite failures

[ebotcazou at gcc dot gnu dot org]

------- Comment #5 from ebotcazou at gcc dot gnu dot org  2010-06-11 21:29 -------
*** Bug 44494 has been marked as a duplicate of this bug. ***


-- 

ebotcazou at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ro at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44484

[Bug rtl-optimization/44484] [4.6 regression] revision 160260 caused sparc64 testsuite failures

[bernds at gcc dot gnu dot org]

------- Comment #7 from bernds at gcc dot gnu dot org  2010-06-11 21:32 -------
This would appear to be a bug in the sparc backend then; my patch is only
exposing it.  I'll not investigate further and leave this for a Sparc
maintainer since I have no clue about the machine.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44484

[Bug rtl-optimization/44484] [4.6 regression] revision 160260 caused sparc64 testsuite failures

[jakub at gcc dot gnu dot org]

------- Comment #8 from jakub at gcc dot gnu dot org  2010-06-24 10:57 -------
The cas/casx insns only allow (mem (reg)) addressing:
(match_operand:I48MODE 1 "memory_reg_operand" "+m")
(match_operand:DI 1 "memory_reg_operand" "+m")

The memory_reg_operand predicate checks this and fails if it is not a memory
with a single reg, but apparently there is no constraint letter that would
require the same.  So, either we need to add a new constraint letter for memory
that satisfies memory_reg_operand, or find out why predicate hasn't been
consulted.


-- 

jakub at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ebotcazou at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44484

[Bug rtl-optimization/44484] [4.6 regression] revision 160260 caused sparc64 testsuite failures

[ebotcazou at gcc dot gnu dot org]

------- Comment #9 from ebotcazou at gcc dot gnu dot org  2010-06-24 11:06 -------
> The memory_reg_operand predicate checks this and fails if it is not a memory
> with a single reg, but apparently there is no constraint letter that would
> require the same.  So, either we need to add a new constraint letter for memory
> that satisfies memory_reg_operand, or find out why predicate hasn't been
> consulted.

Adding a new constraint letter yields reload failures, presumably because
reload doesn't know how to go from MEM[reg+offset] to MEM[reg] on its own.

Bernd, are you really sure the predicate can be bypassed like that?


-- 

ebotcazou at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|ebotcazou at gcc dot gnu dot|
                   |org                         |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44484

[Bug rtl-optimization/44484] [4.6 regression] revision 160260 caused sparc64 testsuite failures

[bernds at gcc dot gnu dot org]

------- Comment #10 from bernds at gcc dot gnu dot org  2010-07-22 20:02 -------
Huh, I thought I'd replied to this weeks ago - probably wasn't logged in.

Reload can't determine the required structure of a memory address from a
predicate name, so it ignores predicates and only looks at constraints.

One way of fixing this might be to make the mem explicit in the pattern, and
require a register_operand as its address.  It might also work to keep the
memory_operand but add a constraint that only allows single-reg addresses; if
that fails as you say maybe you need to define secondary reloads for it?  Can't
tell for sure without seeing the code and the failure.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44484

[Bug target/44484] [4.6 regression] revision 160260 caused sparc64 testsuite failures

[ebotcazou at gcc dot gnu dot org]

------- Comment #11 from ebotcazou at gcc dot gnu dot org  2010-07-25 21:32 -------
Subject: Bug 44484

Author: ebotcazou
Date: Sun Jul 25 21:32:16 2010
New Revision: 162520

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=162520
Log:
        PR target/44484
        * config/sparc/predicates.md (memory_reg_operand): Delete.
        * config/sparc/sync.md (sync_compare_and_swap): Minor tweaks.
        (*sync_compare_and_swap): Encode the address form in the pattern.
        (*sync_compare_and_swapdi_v8plus): Likewise.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/sparc/predicates.md
    trunk/gcc/config/sparc/sync.md


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44484

[Bug target/44484] [4.6 regression] revision 160260 caused sparc64 testsuite failures

[ebotcazou at gcc dot gnu dot org]

------- Comment #12 from ebotcazou at gcc dot gnu dot org  2010-07-25 21:35 -------
At long last.


-- 

ebotcazou at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                URL|                            |http://gcc.gnu.org/ml/gcc-
                   |                            |patches/2010-
                   |                            |07/msg01999.html
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44484