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* [Bug tree-optimization/42893] [4.3/4.4/4.5/4.6 Regression] Missed conditionally dead store elimination [not found] <bug-42893-4@http.gcc.gnu.org/bugzilla/> @ 2011-01-27 3:39 ` law at redhat dot com 2011-02-06 12:28 ` steven at gcc dot gnu.org ` (2 subsequent siblings) 3 siblings, 0 replies; 5+ messages in thread From: law at redhat dot com @ 2011-01-27 3:39 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42893 Jeffrey A. Law <law at redhat dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED CC| |law at redhat dot com Resolution| |FIXED Target Milestone|4.3.6 |4.6.0 --- Comment #10 from Jeffrey A. Law <law at redhat dot com> 2011-01-27 02:27:36 UTC --- DSE1 removes tui_refreshing_registers = 1 as it's a dead store. DOM2 then removes tui_refreshing_registers = 0 because it's able to prove the memory location already holds the value 0. That ultimately leaves an empty function as we leave the tree-ssa optimizers, which is precisely what we want. ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/42893] [4.3/4.4/4.5/4.6 Regression] Missed conditionally dead store elimination [not found] <bug-42893-4@http.gcc.gnu.org/bugzilla/> 2011-01-27 3:39 ` [Bug tree-optimization/42893] [4.3/4.4/4.5/4.6 Regression] Missed conditionally dead store elimination law at redhat dot com @ 2011-02-06 12:28 ` steven at gcc dot gnu.org 2011-02-08 18:56 ` law at gcc dot gnu.org 2011-02-08 19:02 ` law at redhat dot com 3 siblings, 0 replies; 5+ messages in thread From: steven at gcc dot gnu.org @ 2011-02-06 12:28 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42893 Steven Bosscher <steven at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|RESOLVED |REOPENED Resolution|FIXED | --- Comment #11 from Steven Bosscher <steven at gcc dot gnu.org> 2011-02-06 12:24:10 UTC --- The test case should be added to the test suite. ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/42893] [4.3/4.4/4.5/4.6 Regression] Missed conditionally dead store elimination [not found] <bug-42893-4@http.gcc.gnu.org/bugzilla/> 2011-01-27 3:39 ` [Bug tree-optimization/42893] [4.3/4.4/4.5/4.6 Regression] Missed conditionally dead store elimination law at redhat dot com 2011-02-06 12:28 ` steven at gcc dot gnu.org @ 2011-02-08 18:56 ` law at gcc dot gnu.org 2011-02-08 19:02 ` law at redhat dot com 3 siblings, 0 replies; 5+ messages in thread From: law at gcc dot gnu.org @ 2011-02-08 18:56 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42893 --- Comment #12 from Jeffrey A. Law <law at gcc dot gnu.org> 2011-02-08 18:54:21 UTC --- Author: law Date: Tue Feb 8 18:54:12 2011 New Revision: 169933 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=169933 Log: PR tree-optimization/42893 * gcc.tree-ssa/pr42893.c: New test. Added: trunk/gcc/testsuite/gcc.dg/tree-ssa/pr42893.c Modified: trunk/gcc/testsuite/ChangeLog ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/42893] [4.3/4.4/4.5/4.6 Regression] Missed conditionally dead store elimination [not found] <bug-42893-4@http.gcc.gnu.org/bugzilla/> ` (2 preceding siblings ...) 2011-02-08 18:56 ` law at gcc dot gnu.org @ 2011-02-08 19:02 ` law at redhat dot com 3 siblings, 0 replies; 5+ messages in thread From: law at redhat dot com @ 2011-02-08 19:02 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42893 Jeffrey A. Law <law at redhat dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|REOPENED |RESOLVED Resolution| |FIXED --- Comment #13 from Jeffrey A. Law <law at redhat dot com> 2011-02-08 18:55:44 UTC --- Testcase added. ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/42893] New: [4.3/4.4/4.5 Regression] Missed conditionally dead store elimination @ 2010-01-28 7:17 steven at gcc dot gnu dot org 2010-05-22 18:35 ` [Bug tree-optimization/42893] [4.3/4.4/4.5/4.6 " rguenth at gcc dot gnu dot org 0 siblings, 1 reply; 5+ messages in thread From: steven at gcc dot gnu dot org @ 2010-01-28 7:17 UTC (permalink / raw) To: gcc-bugs Taken from http://embed.cs.utah.edu/embarrassing/jan_10/harvest/source/8A/8AB0B238.shtml: struct frame_info; void tui_registers_changed_hook (void); extern struct frame_info *deprecated_selected_frame; int tui_refreshing_registers = 0; void tui_registers_changed_hook (void) { struct frame_info *fi; fi = deprecated_selected_frame; if (fi) { if (tui_refreshing_registers == 0) { tui_refreshing_registers = 1; tui_refreshing_registers = 0; } } return; } Assembler output from GCC 3.4.6 at -O3 on x86_64: .globl tui_registers_changed_hook .type tui_registers_changed_hook, @function tui_registers_changed_hook: .LFB2: rep ; ret .LFE2: .size tui_registers_changed_hook, .-tui_registers_changed_hook Assembler output from GCC 4.5.0 (r155776) at -O3 on x86_64: .globl tui_registers_changed_hook .type tui_registers_changed_hook, @function tui_registers_changed_hook: .LFB0: .cfi_startproc cmpq $0, deprecated_selected_frame(%rip) je .L1 movl tui_refreshing_registers(%rip), %eax testl %eax, %eax jne .L1 movl $0, tui_refreshing_registers(%rip) .L1: rep ret .cfi_endproc .LFE0: .size tui_registers_changed_hook, .-tui_registers_changed_hook This also confuses the tree optimizers (e.g. GCC now fails to note that the function is pure+const). The .optimized dump: ;; Function tui_registers_changed_hook (tui_registers_changed_hook) tui_registers_changed_hook () { struct frame_info * fi; int tui_refreshing_registers.0; <bb 2>: fi_1 = deprecated_selected_frame; if (fi_1 != 0B) goto <bb 3>; else goto <bb 5>; <bb 3>: tui_refreshing_registers.0_2 = tui_refreshing_registers; if (tui_refreshing_registers.0_2 == 0) goto <bb 4>; else goto <bb 5>; <bb 4>: tui_refreshing_registers = 0; <bb 5>: return; } -- Summary: [4.3/4.4/4.5 Regression] Missed conditionally dead store elimination Product: gcc Version: 4.5.0 Status: UNCONFIRMED Keywords: missed-optimization Severity: normal Priority: P3 Component: tree-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: steven at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42893 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/42893] [4.3/4.4/4.5/4.6 Regression] Missed conditionally dead store elimination 2010-01-28 7:17 [Bug tree-optimization/42893] New: [4.3/4.4/4.5 " steven at gcc dot gnu dot org @ 2010-05-22 18:35 ` rguenth at gcc dot gnu dot org 0 siblings, 0 replies; 5+ messages in thread From: rguenth at gcc dot gnu dot org @ 2010-05-22 18:35 UTC (permalink / raw) To: gcc-bugs ------- Comment #9 from rguenth at gcc dot gnu dot org 2010-05-22 18:13 ------- GCC 4.3.5 is being released, adjusting target milestone. -- rguenth at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- Target Milestone|4.3.5 |4.3.6 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42893 ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2011-02-08 18:56 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- [not found] <bug-42893-4@http.gcc.gnu.org/bugzilla/> 2011-01-27 3:39 ` [Bug tree-optimization/42893] [4.3/4.4/4.5/4.6 Regression] Missed conditionally dead store elimination law at redhat dot com 2011-02-06 12:28 ` steven at gcc dot gnu.org 2011-02-08 18:56 ` law at gcc dot gnu.org 2011-02-08 19:02 ` law at redhat dot com 2010-01-28 7:17 [Bug tree-optimization/42893] New: [4.3/4.4/4.5 " steven at gcc dot gnu dot org 2010-05-22 18:35 ` [Bug tree-optimization/42893] [4.3/4.4/4.5/4.6 " rguenth at gcc dot gnu dot org
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