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From: "ramana at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/66675] New: Could improve vector bit_field_ref style optimizations. Date: Thu, 25 Jun 2015 21:03:00 -0000 [thread overview] Message-ID: <bug-66675-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66675 Bug ID: 66675 Summary: Could improve vector bit_field_ref style optimizations. Product: gcc Version: 5.1.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: ramana at gcc dot gnu.org Target Milestone: --- This example #include <arm_neon.h> int main(int argc, char *argv[]) { int8x8_t a = {argc, 1, 2, 3, 4, 5, 6, 7}; int8x8_t b = {0, 1, 2, 3, 4, 5, 6, 7}; int8x8_t c = vadd_s8(a, b); return c[0]; } or it's variant written in gcc vector speak generate pretty terrible code for AArch64 main: adr x1, .LC0 ld1 {v0.8b}, [x1] ins v0.b[0], w0 adr x0, .LC2 ld1 {v1.8b}, [x0] add v0.8b, v0.8b, v1.8b umov w0, v0.b[0] sxtb w0, w0 ret .size main, .-main This could well be folded down to a simple function that returns just argc. While this is a bit silly to expect in real life, it does show an interesting example.... regards Ramana
next reply other threads:[~2015-06-25 21:03 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-06-25 21:03 ramana at gcc dot gnu.org [this message] 2015-06-25 21:04 ` [Bug tree-optimization/66675] " ramana at gcc dot gnu.org 2015-06-25 21:06 ` [Bug tree-optimization/66675] Could improve vector lane folding style operations ramana at gcc dot gnu.org 2015-06-25 22:41 ` pinskia at gcc dot gnu.org 2015-06-25 22:42 ` pinskia at gcc dot gnu.org 2015-06-25 22:50 ` pinskia at gcc dot gnu.org 2021-08-20 6:01 ` pinskia at gcc dot gnu.org
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