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From: "marc.glisse at normalesup dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/53100] New: Optimize __int128 with range information Date: Tue, 24 Apr 2012 07:08:00 -0000 [thread overview] Message-ID: <bug-53100-4@http.gcc.gnu.org/bugzilla/> (raw) http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53100 Bug #: 53100 Summary: Optimize __int128 with range information Classification: Unclassified Product: gcc Version: 4.8.0 Status: UNCONFIRMED Severity: enhancement Priority: P3 Component: middle-end AssignedTo: unassigned@gcc.gnu.org ReportedBy: marc.glisse@normalesup.org (not sure about the "component" field) In the following program, on x86_64, the first version generates two imulq, while the second generates 4 imulq and 2 mulq. It would be convenient if I could just write the whole code with __int128 and let the compiler do the optimization by tracking the range of numbers. int f(int a,int b,int c,int d,int e,int f){ #if 0 long x=a; long y=b; long z=c; long t=d; long u=e; long v=f; return (z-x)*(__int128)(v-y) < (u-x)*(__int128)(t-y); #else __int128 x=a; __int128 y=b; __int128 z=c; __int128 t=d; __int128 u=e; __int128 v=f; return (z-x)*(v-y) < (u-x)*(t-y); #endif }
next reply other threads:[~2012-04-24 7:08 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-04-24 7:08 marc.glisse at normalesup dot org [this message] 2012-04-29 8:06 ` [Bug middle-end/53100] " marc.glisse at normalesup dot org 2012-04-29 8:43 ` marc.glisse at normalesup dot org 2012-05-01 12:47 ` marc.glisse at normalesup dot org 2021-08-06 0:33 ` [Bug tree-optimization/53100] " pinskia at gcc dot gnu.org 2023-07-21 23:32 ` pinskia at gcc dot gnu.org
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