[Bug rtl-optimization/64151] New: [5 Regression] r2182676caused many regressions

[Bug rtl-optimization/64151] New: [5 Regression] r2182676caused many regressions

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64151

            Bug ID: 64151
           Summary: [5 Regression] r2182676caused many regressions
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hjl.tools at gmail dot com
                CC: wdijkstr at arm dot com
            Target: i686-linux

On Linux/i686, r218266 caused:

FAIL: gcc.dg/hoist-register-pressure-3.c scan-rtl-dump hoist "PRE/HOIST: end of
bb .* copying expression"
FAIL: gcc.dg/torture/stackalign/setjmp-1.c   -O1 -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-1.c   -O1 -mforce-drap -fpic execution
test
FAIL: gcc.dg/torture/stackalign/setjmp-1.c   -O2 -flto -fno-use-linker-plugin
-flto-partition=none -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-1.c   -O2 -flto -fno-use-linker-plugin
-flto-partition=none -mforce-drap -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-1.c   -O2 -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-1.c   -O2 -mforce-drap -fpic execution
test
FAIL: gcc.dg/torture/stackalign/setjmp-1.c   -O3 -fomit-frame-pointer -fpic
execution test
FAIL: gcc.dg/torture/stackalign/setjmp-1.c   -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-1.c   -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions -mforce-drap -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-1.c   -O3 -fomit-frame-pointer
-funroll-loops -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-1.c   -O3 -fomit-frame-pointer
-funroll-loops -mforce-drap -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-1.c   -O3 -fomit-frame-pointer
-mforce-drap -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-1.c   -O3 -g -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-1.c   -O3 -g -mforce-drap -fpic
execution test
FAIL: gcc.dg/torture/stackalign/setjmp-1.c   -Os -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-1.c   -Os -mforce-drap -fpic execution
test
FAIL: gcc.dg/torture/stackalign/setjmp-3.c   -O1 -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-3.c   -O1 -mforce-drap -fpic execution
test
FAIL: gcc.dg/torture/stackalign/setjmp-3.c   -O2 -flto -fno-use-linker-plugin
-flto-partition=none -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-3.c   -O2 -flto -fno-use-linker-plugin
-flto-partition=none -mforce-drap -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-3.c   -O2 -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-3.c   -O2 -mforce-drap -fpic execution
test
FAIL: gcc.dg/torture/stackalign/setjmp-3.c   -O3 -fomit-frame-pointer -fpic
execution test
FAIL: gcc.dg/torture/stackalign/setjmp-3.c   -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-3.c   -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions -mforce-drap -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-3.c   -O3 -fomit-frame-pointer
-funroll-loops -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-3.c   -O3 -fomit-frame-pointer
-funroll-loops -mforce-drap -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-3.c   -O3 -fomit-frame-pointer
-mforce-drap -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-3.c   -O3 -g -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-3.c   -O3 -g -mforce-drap -fpic
execution test
FAIL: gcc.dg/torture/stackalign/setjmp-3.c   -Os -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-3.c   -Os -mforce-drap -fpic execution
test
FAIL: gcc.dg/torture/stackalign/setjmp-4.c   -O1 -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-4.c   -O1 -mforce-drap -fpic execution
test
FAIL: gcc.dg/torture/stackalign/setjmp-4.c   -O2 -flto -fno-use-linker-plugin
-flto-partition=none -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-4.c   -O2 -flto -fno-use-linker-plugin
-flto-partition=none -mforce-drap -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-4.c   -O2 -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-4.c   -O2 -mforce-drap -fpic execution
test
FAIL: gcc.dg/torture/stackalign/setjmp-4.c   -O3 -fomit-frame-pointer -fpic
execution test
FAIL: gcc.dg/torture/stackalign/setjmp-4.c   -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-4.c   -O3 -fomit-frame-pointer
-funroll-all-loops -finline-functions -mforce-drap -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-4.c   -O3 -fomit-frame-pointer
-funroll-loops -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-4.c   -O3 -fomit-frame-pointer
-funroll-loops -mforce-drap -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-4.c   -O3 -fomit-frame-pointer
-mforce-drap -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-4.c   -O3 -g -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-4.c   -O3 -g -mforce-drap -fpic
execution test
FAIL: gcc.dg/torture/stackalign/setjmp-4.c   -Os -fpic execution test
FAIL: gcc.dg/torture/stackalign/setjmp-4.c   -Os -mforce-drap -fpic execution
test
FAIL: gcc.target/i386/ifcvt-onecmpl-abs-1.c scan-assembler cltd
FAIL: gcc.target/i386/pr63527.c scan-assembler-not movl[ \t]%[^,]+, %ebx
FAIL: g++.dg/asan/asan_test.C   -O2  AddressSanitizer_BuiltinLongJmpTest
execution test

when GCC is configured with

--with-arch=corei7 --with-cpu=intel --prefix=/usr/5.0.0 --enable-clocale=gnu
--with-system-zlib --enable-shared --with-demangler-in-ld i686-linux
--with-fpmath=sse --enable-languages=c,c++,fortran,java,lto,objc

[Bug rtl-optimization/64151] [5 Regression] r218266 caused many regressions

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64151

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |wrong-code
           Priority|P3                          |P1
   Target Milestone|---                         |5.0

[Bug rtl-optimization/64151] [5 Regression] r218266 caused many regressions

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64151

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-12-02
     Ever confirmed|0                           |1

--- Comment #1 from H.J. Lu <hjl.tools at gmail dot com> ---
Revert the reg_class change:

diff --git a/gcc/ira-costs.c b/gcc/ira-costs.c
index 72c00cc..16fd6e8 100644
--- a/gcc/ira-costs.c
+++ b/gcc/ira-costs.c
@@ -1466,7 +1466,7 @@ scan_one_insn (rtx_insn *insn)
         && REG_N_SETS (REGNO (SET_DEST (set))) == 1))
       && general_operand (SET_SRC (set), GET_MODE (SET_SRC (set))))
     {
-      enum reg_class cl = ALL_REGS;
+      enum reg_class cl = GENERAL_REGS;
       rtx reg = SET_DEST (set);
       int num = COST_INDEX (REGNO (reg));

fixes those regressions.

[Bug rtl-optimization/64151] [5 Regression] r218266 caused many regressions

[wdijkstr at arm dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64151

--- Comment #2 from Wilco <wdijkstr at arm dot com> ---
(In reply to H.J. Lu from comment #1)
> Revert the reg_class change:
> 
> diff --git a/gcc/ira-costs.c b/gcc/ira-costs.c
> index 72c00cc..16fd6e8 100644
> --- a/gcc/ira-costs.c
> +++ b/gcc/ira-costs.c
> @@ -1466,7 +1466,7 @@ scan_one_insn (rtx_insn *insn)
>          && REG_N_SETS (REGNO (SET_DEST (set))) == 1))
>        && general_operand (SET_SRC (set), GET_MODE (SET_SRC (set))))
>      {
> -      enum reg_class cl = ALL_REGS;
> +      enum reg_class cl = GENERAL_REGS;
>        rtx reg = SET_DEST (set);
>        int num = COST_INDEX (REGNO (reg));
> 
> fixes those regressions.

Confirmed. The intention of this code is to account for reduced memory cost of
constant loads - when they spill they do not need a store, but can be trivially
rematerialized. What happens is that memory_move_cost returns 100 for certain
cases on x86. With ALL_REGS the mem_cost then becomes very negative as it is
not clamped to zero and this forces the register allocator to spill. This is
bad as __builtin_longjmp on x86 loads EBP/ESP directly via 2 separate
instructions which means reload *may* insert spill code inbetween. So if the
base register is spilled and reloaded via EBP, it corrupts ESP:

        movl    -4(%ebp), %edx
        movl    (%edx), %ebp     * restore EBP
        movl    -4(%ebp), %ecx   * oops, this uses a different EBP
        movl    8(%ecx), %esp
        jmp     *%eax

I think there are cases where reload just gives up and inserts dumb spill code
(ie. one reload per use), which means this issue can happen under other
circumstances as well.

It appears ALL_REGS works for x86 and avoids the regression, however this is
not correct either for FP or SIMD registers which would get 100 and then get
spilled.

[Bug rtl-optimization/64151] [5 Regression] r218266 caused many regressions

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64151

Markus Trippelsdorf <trippels at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |trippels at gcc dot gnu.org

--- Comment #3 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
See also PR64156 for the same issue on ppc64.

[Bug rtl-optimization/64151] [5 Regression] r218266 caused many regressions

[izamyatin at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64151

Igor Zamyatin <izamyatin at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |izamyatin at gmail dot com

--- Comment #4 from Igor Zamyatin <izamyatin at gmail dot com> ---
I also see ~5% regression on eg spec2006/456.hmmer for i686 with -O3

[Bug rtl-optimization/64151] [5 Regression] r218266 caused many regressions

[hjl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64151

--- Comment #5 from hjl at gcc dot gnu.org <hjl at gcc dot gnu.org> ---
Author: hjl
Date: Wed Dec  3 13:16:25 2014
New Revision: 218312

URL: https://gcc.gnu.org/viewcvs?rev=218312&root=gcc&view=rev
Log:
Revert r218266

gcc/

    PR rtl-optimization/64151
    PR rtl-optimization/64156
    * ira-costs.c (scan_one_insn): Revert r218266.

gcc/testsuite/

    PR rtl-optimization/64151
    PR rtl-optimization/64156
    * gcc.target/aarch64/remat1.c: Removed.  Revert r218267.

Removed:
    trunk/gcc/testsuite/gcc.target/aarch64/remat1.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/ira-costs.c
    trunk/gcc/testsuite/ChangeLog

[Bug rtl-optimization/64151] [5 Regression] r218266 caused many regressions

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64151

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #6 from H.J. Lu <hjl.tools at gmail dot com> ---
Fixed.

[Bug rtl-optimization/64151] [5 Regression] r218266 caused many regressions

[wdijkstr at arm dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64151

--- Comment #7 from Wilco <wdijkstr at arm dot com> ---
See PR rtl-optimization/64242 for the longjmp issue on i386.