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| ; RUN: opt < %s -indvars -S | FileCheck %s
; These tests ensure that we can compute the trip count of various forms of
; loops. If the trip count of the loop is computable, then we will know what
; the exit value of the loop will be for some value, allowing us to substitute
; it directly into users outside of the loop, making the loop dead.
; CHECK-LABEL: @linear_setne(
; CHECK: ret i32 100
define i32 @linear_setne() {
entry:
br label %loop
loop: ; preds = %loop, %entry
%i = phi i32 [ 0, %entry ], [ %i.next, %loop ] ; <i32> [#uses=3]
%i.next = add i32 %i, 1 ; <i32> [#uses=1]
%c = icmp ne i32 %i, 100 ; <i1> [#uses=1]
br i1 %c, label %loop, label %loopexit
loopexit: ; preds = %loop
ret i32 %i
}
; CHECK-LABEL: @linear_setne_2(
; CHECK: ret i32 100
define i32 @linear_setne_2() {
entry:
br label %loop
loop: ; preds = %loop, %entry
%i = phi i32 [ 0, %entry ], [ %i.next, %loop ] ; <i32> [#uses=3]
%i.next = add i32 %i, 2 ; <i32> [#uses=1]
%c = icmp ne i32 %i, 100 ; <i1> [#uses=1]
br i1 %c, label %loop, label %loopexit
loopexit: ; preds = %loop
ret i32 %i
}
; CHECK-LABEL: @linear_setne_overflow(
; CHECK: ret i32 0
define i32 @linear_setne_overflow() {
entry:
br label %loop
loop: ; preds = %loop, %entry
%i = phi i32 [ 1024, %entry ], [ %i.next, %loop ] ; <i32> [#uses=3]
%i.next = add i32 %i, 1024 ; <i32> [#uses=1]
%c = icmp ne i32 %i, 0 ; <i1> [#uses=1]
br i1 %c, label %loop, label %loopexit
loopexit: ; preds = %loop
ret i32 %i
}
; CHECK-LABEL: @linear_setlt(
; CHECK: ret i32 100
define i32 @linear_setlt() {
entry:
br label %loop
loop: ; preds = %loop, %entry
%i = phi i32 [ 0, %entry ], [ %i.next, %loop ] ; <i32> [#uses=3]
%i.next = add i32 %i, 1 ; <i32> [#uses=1]
%c = icmp slt i32 %i, 100 ; <i1> [#uses=1]
br i1 %c, label %loop, label %loopexit
loopexit: ; preds = %loop
ret i32 %i
}
; CHECK-LABEL: @quadratic_setlt(
; CHECK: ret i32 34
define i32 @quadratic_setlt() {
entry:
br label %loop
loop: ; preds = %loop, %entry
%i = phi i32 [ 7, %entry ], [ %i.next, %loop ] ; <i32> [#uses=4]
%i.next = add i32 %i, 3 ; <i32> [#uses=1]
%i2 = mul i32 %i, %i ; <i32> [#uses=1]
%c = icmp slt i32 %i2, 1000 ; <i1> [#uses=1]
br i1 %c, label %loop, label %loopexit
loopexit: ; preds = %loop
ret i32 %i
}
; CHECK-LABEL: @chained(
; CHECK: ret i32 200
define i32 @chained() {
entry:
br label %loop
loop: ; preds = %loop, %entry
%i = phi i32 [ 0, %entry ], [ %i.next, %loop ] ; <i32> [#uses=3]
%i.next = add i32 %i, 1 ; <i32> [#uses=1]
%c = icmp ne i32 %i, 100 ; <i1> [#uses=1]
br i1 %c, label %loop, label %loopexit
loopexit: ; preds = %loop
br label %loop2
loop2: ; preds = %loop2, %loopexit
%j = phi i32 [ %i, %loopexit ], [ %j.next, %loop2 ] ; <i32> [#uses=3]
%j.next = add i32 %j, 1 ; <i32> [#uses=1]
%c2 = icmp ne i32 %j, 200 ; <i1> [#uses=1]
br i1 %c2, label %loop2, label %loopexit2
loopexit2: ; preds = %loop2
ret i32 %j
}
; CHECK-LABEL: @chained4(
; CHECK: ret i32 400
define i32 @chained4() {
entry:
br label %loop
loop: ; preds = %loop, %entry
%i = phi i32 [ 0, %entry ], [ %i.next, %loop ] ; <i32> [#uses=3]
%i.next = add i32 %i, 1 ; <i32> [#uses=1]
%c = icmp ne i32 %i.next, 100 ; <i1> [#uses=1]
br i1 %c, label %loop, label %loopexit
loopexit: ; preds = %loop
br label %loop2
loop2: ; preds = %loop2, %loopexit
%j = phi i32 [ %i.next, %loopexit ], [ %j.next, %loop2 ] ; <i32> [#uses=3]
%j.next = add i32 %j, 1 ; <i32> [#uses=1]
%c2 = icmp ne i32 %j.next, 200 ; <i1> [#uses=1]
br i1 %c2, label %loop2, label %loopexit2
loopexit2: ; preds = %loop
br label %loop8
loop8: ; preds = %loop2, %loopexit
%k = phi i32 [ %j.next, %loopexit2 ], [ %k.next, %loop8 ] ; <i32> [#uses=3]
%k.next = add i32 %k, 1 ; <i32> [#uses=1]
%c8 = icmp ne i32 %k.next, 300 ; <i1> [#uses=1]
br i1 %c8, label %loop8, label %loopexit8
loopexit8: ; preds = %loop2
br label %loop9
loop9: ; preds = %loop2, %loopexit
%l = phi i32 [ %k.next, %loopexit8 ], [ %l.next, %loop9 ] ; <i32> [#uses=3]
%l.next = add i32 %l, 1 ; <i32> [#uses=1]
%c9 = icmp ne i32 %l.next, 400 ; <i1> [#uses=1]
br i1 %c9, label %loop9, label %loopexit9
loopexit9: ; preds = %loop2
ret i32 %l.next
}
; PR18449. Check that the early exit is reduced to never taken.
;
; CHECK-LABEL: @twoexit
; CHECK-LABEL: loop:
; CHECK: phi
; CHECK: br i1 false
; CHECK: br
; CHECK: ret
define void @twoexit() {
"function top level":
br label %loop
loop: ; preds = %body, %"function top level"
%0 = phi i64 [ 0, %"function top level" ], [ %2, %body ]
%1 = icmp ugt i64 %0, 2
br i1 %1, label %fail, label %body
fail: ; preds = %loop
tail call void @bounds_fail()
unreachable
body: ; preds = %loop
%2 = add i64 %0, 1
%3 = icmp slt i64 %2, 3
br i1 %3, label %loop, label %out
out: ; preds = %body
ret void
}
declare void @bounds_fail()
|