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* [Bug target/61051] New: Duplicated instructions in both conditional branches @ 2014-05-04 4:15 carrot at google dot com 2015-03-25 4:24 ` [Bug target/61051] " msebor at gcc dot gnu.org ` (3 more replies) 0 siblings, 4 replies; 5+ messages in thread From: carrot at google dot com @ 2014-05-04 4:15 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=61051 Bug ID: 61051 Summary: Duplicated instructions in both conditional branches Product: gcc Version: 4.10.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target Assignee: unassigned at gcc dot gnu.org Reporter: carrot at google dot com Target: powerpc64le-grtev4-linux-gnu Source code: extern int* foo1 ( long* ); extern int *foo2 ( long *, long *); extern void foo3 (long, long); void bar() { long d, f, x, s, r; int *p; d = 1; if (foo1(&r)) { p = foo2( &d, &x); if( x != *p ) s = 1; else s = 2; if( r > 0 ) f = 1 + d; else f = d; foo3 (f, d); *p = s; } } Compile it with options -O2 -m64 -mcpu=power8, gcc generates: bar: 0: addis 2,12,.TOC.-0b@ha addi 2,2,.TOC.-0b@l .localentry bar,.-bar mflr 0 std 30,-16(1) std 31,-8(1) li 9,1 std 0,16(1) stdu 1,-80(1) addi 3,1,32 std 9,48(1) bl foo1 nop cmpdi 7,3,0 beq 7,.L1 addi 3,1,48 addi 4,1,40 bl foo2 nop ld 10,40(1) li 30,1 lwa 9,0(3) mr 31,3 cmpd 7,9,10 beq 7,.L12 // C ld 9,32(1) // A1 cmpdi 7,9,0 // A2 ble 7,.L4 .L13: ld 4,48(1) addi 3,4,1 .L5: bl foo3 nop stw 30,0(31) .L1: addi 1,1,80 ld 0,16(1) ld 30,-16(1) ld 31,-8(1) mtlr 0 blr .p2align 4,,15 .L12: ld 9,32(1) // B1 li 30,2 cmpdi 7,9,0 // B2 bgt 7,.L13 .L4: ld 3,48(1) mr 4,3 b .L5 .long 0 .byte 0,0,0,1,128,2,0,0 .size bar,.-bar Instruction C is a conditional branch. In both branches A1 and B1 are same instructions, they can be moved to before C. If we use a different conditional register, instructions A2 and B2 can also be moved before C. ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/61051] Duplicated instructions in both conditional branches 2014-05-04 4:15 [Bug target/61051] New: Duplicated instructions in both conditional branches carrot at google dot com @ 2015-03-25 4:24 ` msebor at gcc dot gnu.org 2015-03-25 8:45 ` steven at gcc dot gnu.org ` (2 subsequent siblings) 3 siblings, 0 replies; 5+ messages in thread From: msebor at gcc dot gnu.org @ 2015-03-25 4:24 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61051 Martin Sebor <msebor at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Target|powerpc64le-grtev4-linux-gn |powerpc64*-*-linux-* |u | CC| |msebor at gcc dot gnu.org --- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> --- The latest trunk still emits code that's comparable to the assembly in the Description, both on powerpc64le and powerpc64. ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug target/61051] Duplicated instructions in both conditional branches 2014-05-04 4:15 [Bug target/61051] New: Duplicated instructions in both conditional branches carrot at google dot com 2015-03-25 4:24 ` [Bug target/61051] " msebor at gcc dot gnu.org @ 2015-03-25 8:45 ` steven at gcc dot gnu.org 2021-07-18 21:09 ` [Bug tree-optimization/61051] " pinskia at gcc dot gnu.org 2021-07-18 21:12 ` pinskia at gcc dot gnu.org 3 siblings, 0 replies; 5+ messages in thread From: steven at gcc dot gnu.org @ 2015-03-25 8:45 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61051 Steven Bosscher <steven at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |WAITING Last reconfirmed| |2015-03-25 Ever confirmed|0 |1 --- Comment #2 from Steven Bosscher <steven at gcc dot gnu.org> --- This is code hoisting. That's not performed at -O2. Try -Os. ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/61051] Duplicated instructions in both conditional branches 2014-05-04 4:15 [Bug target/61051] New: Duplicated instructions in both conditional branches carrot at google dot com 2015-03-25 4:24 ` [Bug target/61051] " msebor at gcc dot gnu.org 2015-03-25 8:45 ` steven at gcc dot gnu.org @ 2021-07-18 21:09 ` pinskia at gcc dot gnu.org 2021-07-18 21:12 ` pinskia at gcc dot gnu.org 3 siblings, 0 replies; 5+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-07-18 21:09 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61051 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Component|target |tree-optimization Status|WAITING |RESOLVED Resolution|--- |FIXED Target Milestone|--- |10.0 Keywords| |missed-optimization --- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Fixed on the trunk: x.0_4 = x; if (_3 != x.0_4) goto <bb 5>; [66.00%] else goto <bb 4>; [34.00%] <bb 4> [local count: 195204118]: <bb 5> [local count: 574129753]: # prephitmp_24 = PHI <1(3), 2(4)> r.1_5 = r; pretmp_26 = d; if (r.1_5 > 0) goto <bb 6>; [59.00%] else goto <bb 7>; [41.00%] <bb 6> [local count: 338736556]: f_18 = pretmp_26 + 1; <bb 7> [local count: 574129754]: # f_9 = PHI <f_18(6), pretmp_26(5)> I think it has been fixed in since at least GCC 10 even. ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/61051] Duplicated instructions in both conditional branches 2014-05-04 4:15 [Bug target/61051] New: Duplicated instructions in both conditional branches carrot at google dot com ` (2 preceding siblings ...) 2021-07-18 21:09 ` [Bug tree-optimization/61051] " pinskia at gcc dot gnu.org @ 2021-07-18 21:12 ` pinskia at gcc dot gnu.org 3 siblings, 0 replies; 5+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-07-18 21:12 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61051 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Target Milestone|10.0 |7.0 --- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Rather since GCC 7. ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2021-07-18 21:12 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2014-05-04 4:15 [Bug target/61051] New: Duplicated instructions in both conditional branches carrot at google dot com 2015-03-25 4:24 ` [Bug target/61051] " msebor at gcc dot gnu.org 2015-03-25 8:45 ` steven at gcc dot gnu.org 2021-07-18 21:09 ` [Bug tree-optimization/61051] " pinskia at gcc dot gnu.org 2021-07-18 21:12 ` pinskia at gcc dot gnu.org
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