[Bug target/17390] missing floating point compare optimization
--- Comment #14 from ubizjak at gmail dot com 2007-08-23 08:33 --- Patch at http://gcc.gnu.org/ml/gcc-patches/2007-08/msg01513.html. This is target-only patch that fakes fcomi instructions. It doesn't need to rescan insn stream and creates the same output as in Comment #8. It also doesn't ice for the testcase in Comment #10. -- ubizjak at gmail dot com changed: What|Removed |Added URL|http://gcc.gnu.org/ml/gcc- |http://gcc.gnu.org/ml/gcc- |patches/2005- |patches/2007- |10/msg01298.html|08/msg01513.html http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17390
[Bug target/17390] missing floating point compare optimization
--- Comment #15 from uros at gcc dot gnu dot org 2007-08-23 14:23 --- Subject: Bug 17390 Author: uros Date: Thu Aug 23 14:23:40 2007 New Revision: 127742 URL: http://gcc.gnu.org/viewcvs?root=gccview=revrev=127742 Log: PR target/17390 * config/i386/i386.c (ix86_expand_fp_compare): Expand fp comparison to fake fcomi i387 instruction for !TARGET_CMOVE. (ix86_expand_branch): Expand natural sequence with one jump for all targets, not only TARGET_CMOVE. * config/i386/i386.md (*cmpfp_0_cc): New define_insn_and_split pattern to implement fake fcomi sequence. Split instruction after reload to correct compare sequences. (*cmpfp_xf_cc): Ditto. (*cmpfp_mode_cc): Ditto. (*cmpfp_u_cc): Ditto. (*cmpfp_mode_cc): Ditto. testsuite/ChangeLog: PR target/17390 * gcc.target/i386/pr17390.c: New test. Added: trunk/gcc/testsuite/gcc.target/i386/pr17390.c Modified: trunk/gcc/ChangeLog trunk/gcc/config/i386/i386.c trunk/gcc/config/i386/i386.md trunk/gcc/testsuite/ChangeLog -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17390
[Bug target/17390] missing floating point compare optimization
--- Comment #16 from ubizjak at gmail dot com 2007-08-23 14:26 --- Fixed. -- ubizjak at gmail dot com changed: What|Removed |Added Status|ASSIGNED|RESOLVED Resolution||FIXED Target Milestone|--- |4.3.0 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17390
[Bug target/17390] missing floating point compare optimization
--- Comment #13 from ubizjak at gmail dot com 2007-05-18 15:13 --- (In reply to comment #12) ping This patch needs to be ported to dataflow infrastructure [1] and has to be re-thought a bit. [1]: http://gcc.gnu.org/ml/gcc-patches/2006-05/msg00040.html -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17390
[Bug target/17390] missing floating point compare optimization
--- Comment #12 from fxcoudert at gcc dot gnu dot org 2007-05-10 23:15 --- ping -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17390
[Bug target/17390] missing floating point compare optimization
--- Comment #11 from pluto at agmk dot net 2006-07-25 11:33 --- ping -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17390
[Bug target/17390] missing floating point compare optimization
--- Comment #10 from pluto at agmk dot net 2006-05-01 08:05 ---
(In reply to comment #9)
Created an attachment (id=10666)
-- (http://gcc.gnu.org/bugzilla/attachment.cgi?id=10666action=view) [edit]
patch to SVN GCC: (GNU) 4.2.0 20060117 (experimental)
this patch ICEs recent x86-64 gcc:
$ ./xgcc -B. -v
Reading specs from ./specs
Target: x86_64-pld-linux
Configured with: ../configure --prefix=/usr --with-local-prefix=/usr/local
--libdir=/usr/lib64 --libexecdir=/usr/lib64 --infodir=/usr/share/info
--mandir=/usr/share/man --x-libraries=/usr/lib64 --enable-shared
--enable-threads=posix --enable-languages=c,c++ --enable-c99 --enable-long-long
--enable-multilib --enable-nls --disable-werror --with-gnu-as --with-gnu-ld
--with-demangler-in-ld --with-system-zlib --with-slibdir=/lib64
--without-system-libunwind --without-x --with-long-double-128
--with-gxx-include-dir=/usr/include/c++/4.2.0 --disable-libstdcxx-pch
--enable-__cxa_atexit --enable-libstdcxx-allocator=new x86_64-pld-linux
Thread model: posix
gcc version 4.2.0 20060428 (experimental) (PLD-Linux)
$ cat T1.c
void test(double x) { if (x 0.0); }
$ ./xgcc -B. T1.c -m32
T1.c: In function #8216;test#8217;:
T1.c:1: internal compiler error: in bsi_last, at tree-flow-inline.h:683
$ cat T2.cpp
struct S { ~S(); };
void bar();
void foo()
{
S s;
bar();
}
$ ./xgcc -B. T2.cpp -m32
T2.cpp: In function #8216;void foo()#8217;:
T2.cpp:7: internal compiler error: in bsi_last, at tree-flow-inline.h:683
--
pluto at agmk dot net changed:
What|Removed |Added
CC||pluto at agmk dot net
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17390
[Bug target/17390] missing floating point compare optimization
--- Comment #8 from uros at kss-loka dot si 2006-01-18 09:50 --- (In reply to comment #7) Hmm, I get (but that looks like different branch predictions): It looks that your default is -mtune=pentium. _testf: fldl4(%esp) ftst fnstsw %ax testb $64, %ah jne L10 ftst fnstsw %ax fstp%st(0) testb $69, %ah jne L5 fld1 ret .align 2,0x90 L10: fstp%st(0) fldz ret L5: fldsLC2 ret With proposed patch, this code is compiled to (-O2 -ffast-math -mtune=pentium -fomit-frame-pointer): testf: fldl 4(%esp) ftst fnstsw %ax fstp %st(0) testb $64, %ah jne .L10 testb $69, %ah jne .L5 fld1 ret .p2align 4,,7 .L10: fldz ret .L5: flds .LC2 ret and for -mtune=i686: testf: fldl 4(%esp) ftst fnstsw %ax fstp %st(0) sahf je .L10 jbe .L5 fld1 ret .p2align 4,,7 .L10: fldz .p2align 4,,8 ret .L5: flds .LC2 .p2align 4,,4 ret BTW: I'll attach a patch, rediffed to current SVN. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17390
[Bug target/17390] missing floating point compare optimization
--- Comment #9 from uros at kss-loka dot si 2006-01-18 09:53 --- Created an attachment (id=10666) -- (http://gcc.gnu.org/bugzilla/attachment.cgi?id=10666action=view) patch to SVN GCC: (GNU) 4.2.0 20060117 (experimental) -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17390
[Bug target/17390] missing floating point compare optimization
--- Comment #7 from pinskia at gcc dot gnu dot org 2006-01-18 04:57 --- Hmm, I get (but that looks like different branch predictions): _testf: fldl4(%esp) ftst fnstsw %ax testb $64, %ah jne L10 ftst fnstsw %ax fstp%st(0) testb $69, %ah jne L5 fld1 ret .align 2,0x90 L10: fstp%st(0) fldz ret L5: fldsLC2 ret -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17390
[Bug target/17390] missing floating point compare optimization
--- Comment #6 from uros at kss-loka dot si 2005-10-24 06:29 --- Some discussion can be found in this thread: http://gcc.gnu.org/ml/gcc/2005-10/msg00574.html A new version of patch is here (post-reload machine dependant pass): http://gcc.gnu.org/ml/gcc-patches/2005-10/msg01298.html -- uros at kss-loka dot si changed: What|Removed |Added URL|http://gcc.gnu.org/ml/gcc- |http://gcc.gnu.org/ml/gcc- |patches/2005- |patches/2005- |10/msg01126.html|10/msg01298.html http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17390
[Bug target/17390] missing floating point compare optimization
--- Comment #4 from uros at kss-loka dot si 2005-10-19 12:29 --- Patch here: http://gcc.gnu.org/ml/gcc-patches/2005-10/msg01126.html -- uros at kss-loka dot si changed: What|Removed |Added AssignedTo|unassigned at gcc dot gnu |uros at kss-loka dot si |dot org | URL||http://gcc.gnu.org/ml/gcc- ||patches/2005- ||10/msg01126.html Status|NEW |ASSIGNED Keywords||patch Last reconfirmed|2005-09-24 16:56:00 |2005-10-19 12:29:11 date|| http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17390
[Bug target/17390] missing floating point compare optimization
--- Comment #5 from steven at gcc dot gnu dot org 2005-10-19 13:13 --- That patch is yet another example of why we constantly keep having compile time problems. Just add more, and more, and more, and more. And act surprised when someone notices that gcc 4.1 is four times as slow as 2.95.3 for very little benefit on x86 at least. Why a new pass over all insns, instead of e.g. teaching postreload cse or postreload gcse about this kind of thing? -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17390
