loop-rotate.ll
2.04 KB
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; RUN: llc -mtriple=i686-linux < %s | FileCheck %s
; Don't rotate the loop if the number of fall through to exit is not larger
; than the number of fall through to header.
define void @no_rotate() {
; CHECK-LABEL: no_rotate
; CHECK: %entry
; CHECK: %header
; CHECK: %middle
; CHECK: %latch1
; CHECK: %latch2
; CHECK: %end
entry:
br label %header
header:
%val1 = call i1 @foo()
br i1 %val1, label %middle, label %end
middle:
%val2 = call i1 @foo()
br i1 %val2, label %latch1, label %end
latch1:
%val3 = call i1 @foo()
br i1 %val3, label %latch2, label %header
latch2:
%val4 = call i1 @foo()
br label %header
end:
ret void
}
define void @do_rotate() {
; CHECK-LABEL: do_rotate
; CHECK: %entry
; CHECK: %then
; CHECK: %else
; CHECK: %latch1
; CHECK: %latch2
; CHECK: %header
; CHECK: %end
entry:
%val0 = call i1 @foo()
br i1 %val0, label %then, label %else
then:
call void @a()
br label %header
else:
call void @b()
br label %header
header:
%val1 = call i1 @foo()
br i1 %val1, label %latch1, label %end
latch1:
%val3 = call i1 @foo()
br i1 %val3, label %latch2, label %header
latch2:
%val4 = call i1 @foo()
br label %header
end:
ret void
}
; The loop structure is same as in @no_rotate, but the loop header's predecessor
; doesn't fall through to it, so it should be rotated to get exit fall through.
define void @do_rotate2() {
; CHECK-LABEL: do_rotate2
; CHECK: %entry
; CHECK: %then
; CHECK: %middle
; CHECK: %latch1
; CHECK: %latch2
; CHECK: %header
; CHECK: %exit
entry:
%val0 = call i1 @foo()
br i1 %val0, label %then, label %header, !prof !1
then:
call void @a()
br label %end
header:
%val1 = call i1 @foo()
br i1 %val1, label %middle, label %exit
middle:
%val2 = call i1 @foo()
br i1 %val2, label %latch1, label %exit
latch1:
%val3 = call i1 @foo()
br i1 %val3, label %latch2, label %header
latch2:
%val4 = call i1 @foo()
br label %header
exit:
call void @b()
br label %end
end:
ret void
}
declare i1 @foo()
declare void @a()
declare void @b()
!1 = !{!"branch_weights", i32 10, i32 1}