[Bug target/58779] [4.7/4.8/4.9 Regression] wrong code at -O1 on x86_64-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58779 Uroš Bizjak changed: What|Removed |Added Status|ASSIGNED|RESOLVED Resolution|--- |FIXED --- Comment #12 from Uroš Bizjak --- Fixed.
[Bug target/58779] [4.7/4.8/4.9 Regression] wrong code at -O1 on x86_64-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58779 --- Comment #11 from uros at gcc dot gnu.org --- Author: uros Date: Sat Oct 26 06:09:02 2013 New Revision: 204088 URL: http://gcc.gnu.org/viewcvs?rev=204088&root=gcc&view=rev Log: Backport from mainline 2013-10-22 Uros Bizjak PR target/58779 * config/i386/i386.c (put_condition_code) : Remove CCCmode handling. : Return 'c' suffix for CCCmode. : Return 'nc' suffix for CCCmode. (ix86_cc_mode) : Do not generate overflow checks. * config/i386/i386.md (*sub3_cconly_overflow): Remove. (*sub3_cc_overflow): Ditto. (*subsi3_zext_cc_overflow): Ditto. Backport from mainline 2013-10-19 Uros Bizjak PR target/58792 * config/i386/i386.c (ix86_function_value_regno): Add DX_REG, ST1_REG and XMM1_REG for 32bit and 64bit targets. Also add DI_REG and SI_REG for 64bit SYSV ABI targets. testsuite/ChangeLog: Backport from mainline 2013-10-22 Uros Bizjak PR target/58779 * gcc.target/i386/pr30315.c: Remove MINUSCC, DECCC, MINUSCCONLY and MINUSCCZEXT defines. Update scan-assembler dg directive. * gcc.dg/torture/pr58779.c: New test. Added: branches/gcc-4_7-branch/gcc/testsuite/gcc.dg/torture/pr58779.c Modified: branches/gcc-4_7-branch/gcc/ChangeLog branches/gcc-4_7-branch/gcc/config/i386/i386.c branches/gcc-4_7-branch/gcc/config/i386/i386.md branches/gcc-4_7-branch/gcc/testsuite/ChangeLog branches/gcc-4_7-branch/gcc/testsuite/gcc.target/i386/pr30315.c
[Bug target/58779] [4.7/4.8/4.9 Regression] wrong code at -O1 on x86_64-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58779 --- Comment #10 from uros at gcc dot gnu.org --- Author: uros Date: Sat Oct 26 06:02:20 2013 New Revision: 204087 URL: http://gcc.gnu.org/viewcvs?rev=204087&root=gcc&view=rev Log: Backport from mainline 2013-10-22 Uros Bizjak PR target/58779 * config/i386/i386.c (put_condition_code) : Remove CCCmode handling. : Return 'c' suffix for CCCmode. : Return 'nc' suffix for CCCmode. (ix86_cc_mode) : Do not generate overflow checks. * config/i386/i386.md (*sub3_cconly_overflow): Remove. (*sub3_cc_overflow): Ditto. (*subsi3_zext_cc_overflow): Ditto. Backport from mainline 2013-10-19 Uros Bizjak PR target/58792 * config/i386/i386.c (ix86_function_value_regno): Add DX_REG, ST1_REG and XMM1_REG for 32bit and 64bit targets. Also add DI_REG and SI_REG for 64bit SYSV ABI targets. testsuite/ChangeLog: Backport from mainline 2013-10-22 Uros Bizjak PR target/58779 * gcc.target/i386/pr30315.c: Remove MINUSCC, DECCC, MINUSCCONLY and MINUSCCZEXT defines. Update scan-assembler dg directive. * gcc.dg/torture/pr58779.c: New test. Added: branches/gcc-4_8-branch/gcc/testsuite/gcc.dg/torture/pr58779.c Modified: branches/gcc-4_8-branch/gcc/ChangeLog branches/gcc-4_8-branch/gcc/config/i386/i386.c branches/gcc-4_8-branch/gcc/config/i386/i386.md branches/gcc-4_8-branch/gcc/testsuite/ChangeLog branches/gcc-4_8-branch/gcc/testsuite/gcc.target/i386/pr30315.c
[Bug target/58779] [4.7/4.8/4.9 Regression] wrong code at -O1 on x86_64-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58779 --- Comment #9 from Uroš Bizjak --- Fixed on trunk sofar.
[Bug target/58779] [4.7/4.8/4.9 Regression] wrong code at -O1 on x86_64-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58779 Uroš Bizjak changed: What|Removed |Added URL||http://gcc.gnu.org/ml/gcc-p ||atches/2013-10/msg01826.htm ||l --- Comment #8 from Uroš Bizjak --- Patch at [1]. [1] http://gcc.gnu.org/ml/gcc-patches/2013-10/msg01826.html
[Bug target/58779] [4.7/4.8/4.9 Regression] wrong code at -O1 on x86_64-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58779 --- Comment #7 from uros at gcc dot gnu.org --- Author: uros Date: Tue Oct 22 18:35:53 2013 New Revision: 203935 URL: http://gcc.gnu.org/viewcvs?rev=203935&root=gcc&view=rev Log: PR target/58779 * config/i386/i386.c (put_condition_code) : Remove CCCmode handling. : Return 'c' suffix for CCCmode. : Return 'nc' suffix for CCCmode. (ix86_cc_mode) : Do not generate overflow checks. * config/i386/i386.md (*sub3_cconly_overflow): Remove. (*sub3_cc_overflow): Ditto. (*subsi3_zext_cc_overflow): Ditto. testsuite/ChangeLog: PR target/58779 * gcc.target/i386/pr30315.c: Remove MINUSCC, DECCC, MINUSCCONLY and MINUSCCZEXT defines. Update scan-assembler dg directive. * gcc.dg/torture/pr58779.c: New test. Added: trunk/gcc/testsuite/gcc.dg/torture/pr58779.c Modified: trunk/gcc/ChangeLog trunk/gcc/config/i386/i386.c trunk/gcc/config/i386/i386.md trunk/gcc/testsuite/ChangeLog trunk/gcc/testsuite/gcc.target/i386/pr30315.c
[Bug target/58779] [4.7/4.8/4.9 Regression] wrong code at -O1 on x86_64-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58779 --- Comment #6 from Uroš Bizjak --- Created attachment 31067 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=31067&action=edit Proposed patch that removes MINUS overflow checks Patch in testing.
[Bug target/58779] [4.7/4.8/4.9 Regression] wrong code at -O1 on x86_64-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58779
--- Comment #5 from Uroš Bizjak ---
combine pass is converting:
(insn 21 20 22 4 (parallel [
(set (reg:SI 73)
(minus:SI (reg:SI 64 [ a.2 ])
(reg:SI 59 [ iftmp.3 ])))
(clobber (reg:CC 17 flags))
]) pr58779.c:8 286 {*subsi_1}
(expr_list:REG_DEAD (reg:SI 59 [ iftmp.3 ])
(expr_list:REG_UNUSED (reg:CC 17 flags)
(nil
(insn 22 21 23 4 (set (reg:CC 17 flags)
(compare:CC (reg:SI 64 [ a.2 ])
(reg:SI 73))) pr58779.c:8 6 {*cmpsi_1}
(expr_list:REG_DEAD (reg:SI 73)
(expr_list:REG_DEAD (reg:SI 64 [ a.2 ])
(nil
(jump_insn 23 22 24 4 (set (pc)
(if_then_else (ltu (reg:CC 17 flags)
(const_int 0 [0]))
(label_ref 27)
(pc))) pr58779.c:8 596 {*jcc_1}
(expr_list:REG_DEAD (reg:CC 17 flags)
(expr_list:REG_BR_PROB (const_int 9996 [0x270c])
(nil)))
to:
(insn 22 21 23 4 (set (reg:CCC 17 flags)
(compare:CCC (minus:SI (reg:SI 64 [ a.2 ])
(reg:SI 59 [ iftmp.3 ]))
(reg:SI 64 [ a.2 ]))) pr58779.c:8 316 {*subsi3_cconly_overflow}
(expr_list:REG_DEAD (reg:SI 59 [ iftmp.3 ])
(expr_list:REG_DEAD (reg:SI 64 [ a.2 ])
(nil
(jump_insn 23 22 24 4 (set (pc)
(if_then_else (gtu (reg:CCC 17 flags)
(const_int 0 [0]))
(label_ref 27)
(pc))) pr58779.c:8 596 {*jcc_1}
(expr_list:REG_DEAD (reg:CC 17 flags)
(expr_list:REG_BR_PROB (const_int 9996 [0x270c])
(nil)))
To satisfy the *subsi3_cconly_overflow pattern, the operands of the compare are
swapped, and this reflects in changing jump insn condition from LTU to GTU.
The LTU in CCmode results in "jb" instruction, whereas GTU in CCCmode in
unpatched gcc also results in "jb". As Mikael figured out in Comment #2, we
should jump on Not-Carry condition here.
It looks to me that MINUS overflow checks are NOT modelled correctly. To hide
this problem, GTU and LEU conditions operate with inverted flag check, as can
be seen in i386.c, put_condition_code:
case GTU:
if (mode == CCmode)
suffix = fp ? "nbe" : "a";
else if (mode == CCCmode)
suffix = "b";
...
case LEU:
if (mode == CCmode)
suffix = "be";
else if (mode == CCCmode)
suffix = fp ? "nb" : "ae";
...
As can be seen from the above code, hecks in CCCmode are inverted.
So, the solution is simply to remove wrong MINUS overflow checks, as in to-be
attached patch.
[Bug target/58779] [4.7/4.8/4.9 Regression] wrong code at -O1 on x86_64-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58779 Uroš Bizjak changed: What|Removed |Added Target|x86_64-*-linux-gnu |x86 Status|NEW |ASSIGNED Assignee|unassigned at gcc dot gnu.org |ubizjak at gmail dot com --- Comment #4 from Uroš Bizjak --- (In reply to Andrew Pinski from comment #3) > Looks like this is a latent target bug as that change should not effect RTL > at all (well the beginning expansion to RTL will be changed). Yes, it is target problem with overflow patterns. MINUS overflow patterns are invalid and should be removed. I have a patch in testing.
[Bug target/58779] [4.7/4.8/4.9 Regression] wrong code at -O1 on x86_64-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58779 Andrew Pinski changed: What|Removed |Added Target||x86_64-*-linux-gnu Component|rtl-optimization|target --- Comment #3 from Andrew Pinski --- (In reply to Mikael Pettersson from comment #2) > Started with r180109. CC:ing author. Looks like this is a latent target bug as that change should not effect RTL at all (well the beginning expansion to RTL will be changed).
