2011-08-29-SchedCycle.ll
1.29 KB
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; RUN: llc %s -mtriple=thumbv7-apple-darwin -mcpu=cortex-a8 -o -
; When a i64 sub is expanded to subc + sube.
; libcall #1
; \
; \ subc
; \ / \
; \ / \
; \ / libcall #2
; sube
;
; If the libcalls are not serialized (i.e. both have chains which are dag
; entry), legalizer can serialize them in arbitrary orders. If it's
; unlucky, it can force libcall #2 before libcall #1 in the above case.
;
; subc
; |
; libcall #2
; |
; libcall #1
; |
; sube
;
; However since subc and sube are "glued" together, this ends up being a
; cycle when the scheduler combine subc and sube as a single scheduling
; unit.
;
; The right solution is to fix LegalizeType too chains the libcalls together.
; However, LegalizeType is not processing nodes in order. The fix now is to
; fix subc / sube (and addc / adde) to use physical register dependency instead.
; rdar://10019576
define void @t() nounwind {
entry:
%tmp = load i64, i64* undef, align 4
%tmp5 = udiv i64 %tmp, 30
%tmp13 = and i64 %tmp5, 64739244643450880
%tmp16 = sub i64 0, %tmp13
%tmp19 = and i64 %tmp16, 63
%tmp20 = urem i64 %tmp19, 3
%tmp22 = and i64 %tmp16, -272346829004752
store i64 %tmp22, i64* undef, align 4
store i64 %tmp20, i64* undef, align 4
ret void
}