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From: "hjl dot tools at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/37364] New: [4.4 Regression] IRA generates ineffient code Date: Thu, 04 Sep 2008 05:45:00 -0000 [thread overview] Message-ID: <bug-37364-682@http.gcc.gnu.org/bugzilla/> (raw) bash-3.2$ cat /tmp/x.c #include <mmintrin.h> extern __m64 x, y; unsigned long long foo(__m64 m) { return _mm_cvtm64_si64(_mm_add_pi32(x, y)); } bash-3.2$ ./xgcc -B./ -march=core2 -S -O2 /tmp/x.c bash-3.2$ cat x.s .file "x.c" .text .p2align 4,,15 .globl foo .type foo, @function foo: .LFB129: .cfi_startproc movq x(%rip), %mm0 paddd y(%rip), %mm0 movq %mm0, -8(%rsp) movq -8(%rsp), %rax ret .cfi_endproc .LFE129: .size foo, .-foo .ident "GCC: (GNU) 4.4.0 20080903 (experimental) [trunk revision 139952]" .section .note.GNU-stack,"",@progbits bash-3.2$ ./xgcc -B./ -march=core2 -S -O2 /tmp/x.c -fno-ira bash-3.2$ cat x.s .file "x.c" .text .p2align 4,,15 .globl foo .type foo, @function foo: .LFB129: .cfi_startproc movq x(%rip), %mm0 paddd y(%rip), %mm0 movd %mm0, %rax ret .cfi_endproc .LFE129: .size foo, .-foo .ident "GCC: (GNU) 4.4.0 20080903 (experimental) [trunk revision 139952]" .section .note.GNU-stack,"",@progbits bash-3.2$ The problem is IRA turns (insn 8 7 14 2 ../../include/mmintrin.h:300 (set (reg:V2SI 61) (plus:V2SI (reg:V2SI 63 [ x ]) (mem/c/i:V2SI (symbol_ref:DI ("y") <var_decl 0x7fd36e03cc80 y>) [2 y+0 S8 A64]))) 992 {*mmx_addv2si3} (expr_list:REG_DEAD (reg:V2SI 63 [ x ]) (nil))) (insn 14 8 20 2 /tmp/x.c:12 (set (reg/i:DI 0 ax) (subreg:DI (reg:V2SI 61) 0)) 89 {*movdi_1_rex64} (expr_list:REG_DEAD (re g:V2SI 61) (nil))) into (insn 26 8 14 2 ../../include/mmintrin.h:300 (set (mem/c:V2SI (plus:DI (reg/f:DI 7 sp) (const_int -8 [0xfffffffffffffff8])) [3 S8 A64]) (reg:V2SI 29 mm0 [orig:63 x ] [63])) 946 {*movv2si_internal_rex64} (nil) ) (insn:HI 14 26 20 2 /tmp/x.c:12 (set (reg/i:DI 0 ax) (mem/c:DI (plus:DI (reg/f:DI 7 sp) (const_int -8 [0xfffffffffffffff8])) [3 S8 A64])) 89 {*movdi_1_r ex64} (nil)) while the old RA generates (insn:HI 14 8 20 2 /tmp/x.c:12 (set (reg/i:DI 0 ax) (reg:DI 29 mm0 [orig:63 x ] [63])) 89 {*movdi_1_rex64} (nil)) The outputs from regmove pass are different. With IRA, we got (insn:HI 8 7 14 2 ../../include/mmintrin.h:300 (set (reg:V2SI 61) (plus:V2SI (reg:V2SI 63 [ x ]) (mem/c/i:V2SI (symbol_ref:DI ("y") <var_decl 0x7f66abfb5c80 y>) [2 y +0 S8 A64]))) 992 {*mmx_addv2si3} (expr_list:REG_DEAD (reg:V2SI 63 [ x ]) (nil))) (insn:HI 14 8 20 2 /tmp/x.c:12 (set (reg/i:DI 0 ax) (subreg:DI (reg:V2SI 61) 0)) 89 {*movdi_1_rex64} (expr_list:REG_DEAD (re g:V2SI 61) (nil))) Without IRA, we got (insn:HI 8 7 14 2 ../../include/mmintrin.h:300 (set (reg:V2SI 63 [ x ]) (plus:V2SI (reg:V2SI 63 [ x ]) (mem/c/i:V2SI (symbol_ref:DI ("y") <var_decl 0x7fd36e03cc80 y>) [2 y+0 S8 A64]))) 992 {*mmx_addv2si3} (nil)) (insn:HI 14 8 20 2 /tmp/x.c:12 (set (reg/i:DI 0 ax) (subreg:DI (reg:V2SI 63 [ x ]) 0)) 89 {*movdi_1_rex64} (expr_list:REG_D EAD (reg:V2SI 63 [ x ]) (nil))) Does it have any impact on code generation? -- Summary: [4.4 Regression] IRA generates ineffient code Product: gcc Version: 4.4.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: middle-end AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: hjl dot tools at gmail dot com GCC target triplet: x86_64-unknown-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37364
next reply other threads:[~2008-09-04 5:45 UTC|newest] Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top 2008-09-04 5:45 hjl dot tools at gmail dot com [this message] 2008-09-04 9:50 ` [Bug middle-end/37364] " rguenth at gcc dot gnu dot org 2008-09-04 16:04 ` hjl dot tools at gmail dot com 2008-09-04 16:14 ` hjl dot tools at gmail dot com 2008-09-04 17:44 ` hjl dot tools at gmail dot com 2008-09-04 17:55 ` hjl dot tools at gmail dot com 2008-09-04 18:40 ` [Bug middle-end/37364] [4.4 Regression] IRA generates inefficient code hjl dot tools at gmail dot com 2008-09-04 19:26 ` vmakarov at redhat dot com 2008-09-04 19:46 ` hjl dot tools at gmail dot com 2008-09-04 20:14 ` rguenth at gcc dot gnu dot org 2008-09-04 20:18 ` hjl dot tools at gmail dot com 2008-09-04 20:32 ` hjl dot tools at gmail dot com 2008-09-06 15:58 ` [Bug target/37364] [4.4 Regression] IRA generates inefficient code due to missing regmove pass ubizjak at gmail dot com 2008-09-06 16:26 ` ubizjak at gmail dot com 2008-09-06 16:50 ` hjl dot tools at gmail dot com 2008-09-09 16:02 ` hjl dot tools at gmail dot com 2008-09-11 13:47 ` bonzini at gnu dot org 2008-09-11 17:34 ` ubizjak at gmail dot com 2008-10-22 3:19 ` mmitchel at gcc dot gnu dot org 2008-10-23 8:44 ` Joey dot ye at intel dot com 2008-10-24 8:37 ` Joey dot ye at intel dot com 2008-10-24 10:12 ` bonzini at gnu dot org 2008-10-24 10:17 ` bonzini at gnu dot org 2008-10-25 4:15 ` Joey dot ye at intel dot com 2008-10-28 1:13 ` hjl dot tools at gmail dot com 2008-10-28 1:21 ` Joey dot ye at intel dot com 2008-10-28 1:37 ` hjl dot tools at gmail dot com 2008-11-04 19:30 ` hjl dot tools at gmail dot com 2008-11-30 20:46 ` steven at gcc dot gnu dot org 2008-11-30 20:53 ` hjl dot tools at gmail dot com 2008-11-30 21:20 ` steven at gcc dot gnu dot org 2008-11-30 21:34 ` steven at gcc dot gnu dot org 2008-12-01 18:27 ` ubizjak at gmail dot com 2008-12-21 18:06 ` hjl dot tools at gmail dot com 2009-01-29 17:13 ` hjl dot tools at gmail dot com 2009-01-29 17:57 ` hjl dot tools at gmail dot com 2009-02-04 7:57 ` bonzini at gnu dot org 2009-02-04 7:58 ` bonzini at gnu dot org
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