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llvm-for-llvmta/test/Transforms/GuardWidening/basic.ll

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2022-04-25 10:02:23 +02:00
; RUN: opt -S -guard-widening < %s | FileCheck %s
; RUN: opt -S -passes=guard-widening < %s | FileCheck %s
declare void @llvm.experimental.guard(i1,...)
; Basic test case: we wide the first check to check both the
; conditions.
define void @f_0(i1 %cond_0, i1 %cond_1) {
; CHECK-LABEL: @f_0(
entry:
; CHECK: %wide.chk = and i1 %cond_0, %cond_1
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %wide.chk) [ "deopt"() ]
; CHECK: ret void
call void(i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
call void(i1, ...) @llvm.experimental.guard(i1 %cond_1) [ "deopt"() ]
ret void
}
; Same as @f_0, but with using a more general notion of postdominance.
define void @f_1(i1 %cond_0, i1 %cond_1) {
; CHECK-LABEL: @f_1(
entry:
; CHECK: %wide.chk = and i1 %cond_0, %cond_1
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %wide.chk) [ "deopt"() ]
; CHECK: br i1 undef, label %left, label %right
call void(i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
br i1 undef, label %left, label %right
left:
br label %merge
right:
br label %merge
merge:
; CHECK: merge:
; CHECK-NOT: call void (i1, ...) @llvm.experimental.guard(
; CHECK: ret void
call void(i1, ...) @llvm.experimental.guard(i1 %cond_1) [ "deopt"() ]
ret void
}
; Like @f_1, but we have some code we need to hoist before we can
; widen a dominanting check.
define void @f_2(i32 %a, i32 %b) {
; CHECK-LABEL: @f_2(
entry:
; CHECK: %cond_0 = icmp ult i32 %a, 10
; CHECK: %cond_1 = icmp ult i32 %b, 10
; CHECK: %wide.chk = and i1 %cond_0, %cond_1
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %wide.chk) [ "deopt"() ]
; CHECK: br i1 undef, label %left, label %right
%cond_0 = icmp ult i32 %a, 10
call void(i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
br i1 undef, label %left, label %right
left:
br label %merge
right:
br label %merge
merge:
%cond_1 = icmp ult i32 %b, 10
call void(i1, ...) @llvm.experimental.guard(i1 %cond_1) [ "deopt"() ]
ret void
}
; Negative test: don't hoist stuff out of control flow
; indiscriminately, since that can make us do more work than needed.
define void @f_3(i32 %a, i32 %b) {
; CHECK-LABEL: @f_3(
entry:
; CHECK: %cond_0 = icmp ult i32 %a, 10
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
; CHECK: br i1 undef, label %left, label %right
%cond_0 = icmp ult i32 %a, 10
call void(i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
br i1 undef, label %left, label %right
left:
; CHECK: left:
; CHECK: %cond_1 = icmp ult i32 %b, 10
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %cond_1) [ "deopt"() ]
; CHECK: ret void
%cond_1 = icmp ult i32 %b, 10
call void(i1, ...) @llvm.experimental.guard(i1 %cond_1) [ "deopt"() ]
ret void
right:
ret void
}
; But hoisting out of control flow is fine if it makes a loop computed
; condition loop invariant. This behavior may require some tuning in
; the future.
define void @f_4(i32 %a, i32 %b) {
; CHECK-LABEL: @f_4(
entry:
; CHECK: %cond_0 = icmp ult i32 %a, 10
; CHECK: %cond_1 = icmp ult i32 %b, 10
; CHECK: %wide.chk = and i1 %cond_0, %cond_1
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %wide.chk) [ "deopt"() ]
; CHECK: br i1 undef, label %loop, label %leave
%cond_0 = icmp ult i32 %a, 10
call void(i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
br i1 undef, label %loop, label %leave
loop:
%cond_1 = icmp ult i32 %b, 10
call void(i1, ...) @llvm.experimental.guard(i1 %cond_1) [ "deopt"() ]
br i1 undef, label %loop, label %leave
leave:
ret void
}
; Hoisting out of control flow is also fine if we can widen the
; dominating check without doing any extra work.
define void @f_5(i32 %a) {
; CHECK-LABEL: @f_5(
entry:
; CHECK: %wide.chk = icmp uge i32 %a, 11
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %wide.chk) [ "deopt"() ]
; CHECK: br i1 undef, label %left, label %right
%cond_0 = icmp ugt i32 %a, 7
call void(i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
br i1 undef, label %left, label %right
left:
%cond_1 = icmp ugt i32 %a, 10
call void(i1, ...) @llvm.experimental.guard(i1 %cond_1) [ "deopt"() ]
ret void
right:
ret void
}
; Negative test: the load from %a can be safely speculated to before
; the first guard, but there is no guarantee that it will produce the
; same value.
define void @f_6(i1* dereferenceable(32) %a, i1* %b, i1 %unknown) {
; CHECK-LABEL: @f_6(
; CHECK: call void (i1, ...) @llvm.experimental.guard(
; CHECK: call void (i1, ...) @llvm.experimental.guard(
; CHECK: ret void
entry:
%cond_0 = load i1, i1* %a
call void(i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
store i1 %unknown, i1* %b
%cond_1 = load i1, i1* %a
call void(i1, ...) @llvm.experimental.guard(i1 %cond_1) [ "deopt"() ]
ret void
}
; All else equal, we try to widen the earliest guard we can. This
; heuristic can use some tuning.
define void @f_7(i32 %a, i1* %cond_buf) {
; CHECK-LABEL: @f_7(
entry:
; CHECK: %cond_1 = load volatile i1, i1* %cond_buf
; CHECK: %cond_3 = icmp ult i32 %a, 7
; CHECK: %wide.chk = and i1 %cond_1, %cond_3
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %wide.chk) [ "deopt"() ]
; CHECK: %cond_2 = load volatile i1, i1* %cond_buf
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %cond_2) [ "deopt"() ]
; CHECK: br i1 undef, label %left, label %right
%cond_1 = load volatile i1, i1* %cond_buf
call void(i1, ...) @llvm.experimental.guard(i1 %cond_1) [ "deopt"() ]
%cond_2 = load volatile i1, i1* %cond_buf
call void(i1, ...) @llvm.experimental.guard(i1 %cond_2) [ "deopt"() ]
br i1 undef, label %left, label %right
left:
%cond_3 = icmp ult i32 %a, 7
call void(i1, ...) @llvm.experimental.guard(i1 %cond_3) [ "deopt"() ]
br label %left
right:
ret void
}
; In this case the earliest dominating guard is in a loop, and we
; don't want to put extra work in there. This heuristic can use some
; tuning.
define void @f_8(i32 %a, i1 %cond_1, i1 %cond_2) {
; CHECK-LABEL: @f_8(
entry:
br label %loop
loop:
call void(i1, ...) @llvm.experimental.guard(i1 %cond_1) [ "deopt"() ]
br i1 undef, label %loop, label %leave
leave:
; CHECK: leave:
; CHECK: %cond_3 = icmp ult i32 %a, 7
; CHECK: %wide.chk = and i1 %cond_2, %cond_3
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %wide.chk) [ "deopt"() ]
; CHECK: br i1 undef, label %loop2, label %leave2
call void(i1, ...) @llvm.experimental.guard(i1 %cond_2) [ "deopt"() ]
br i1 undef, label %loop2, label %leave2
loop2:
%cond_3 = icmp ult i32 %a, 7
call void(i1, ...) @llvm.experimental.guard(i1 %cond_3) [ "deopt"() ]
br label %loop2
leave2:
ret void
}
; In cases like these where there isn't any "obviously profitable"
; widening sites, we refuse to do anything.
define void @f_9(i32 %a, i1 %cond_0, i1 %cond_1) {
; CHECK-LABEL: @f_9(
entry:
br label %first_loop
first_loop:
; CHECK: first_loop:
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
; CHECK: br i1 undef, label %first_loop, label %second_loop
call void(i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
br i1 undef, label %first_loop, label %second_loop
second_loop:
; CHECK: second_loop:
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %cond_1) [ "deopt"() ]
; CHECK: br label %second_loop
call void(i1, ...) @llvm.experimental.guard(i1 %cond_1) [ "deopt"() ]
br label %second_loop
}
; Same situation as in @f_9: no "obviously profitable" widening sites,
; so we refuse to do anything.
define void @f_10(i32 %a, i1 %cond_0, i1 %cond_1) {
; CHECK-LABEL: @f_10(
entry:
br label %loop
loop:
; CHECK: loop:
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
; CHECK: br i1 undef, label %loop, label %no_loop
call void(i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
br i1 undef, label %loop, label %no_loop
no_loop:
; CHECK: no_loop:
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %cond_1) [ "deopt"() ]
; CHECK: ret void
call void(i1, ...) @llvm.experimental.guard(i1 %cond_1) [ "deopt"() ]
ret void
}
; With guards in loops, we're okay hoisting out the guard into the
; containing loop.
define void @f_11(i32 %a, i1 %cond_0, i1 %cond_1) {
; CHECK-LABEL: @f_11(
entry:
br label %inner
inner:
; CHECK: inner:
; CHECK: %wide.chk = and i1 %cond_0, %cond_1
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %wide.chk) [ "deopt"() ]
; CHECK: br i1 undef, label %inner, label %outer
call void(i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
br i1 undef, label %inner, label %outer
outer:
call void(i1, ...) @llvm.experimental.guard(i1 %cond_1) [ "deopt"() ]
br label %inner
}
; Checks that we are adequately guarded against exponential-time
; behavior when hoisting code.
define void @f_12(i32 %a0) {
; CHECK-LABEL: @f_12
; Eliding the earlier 29 multiplications for brevity
; CHECK: %a30 = mul i32 %a29, %a29
; CHECK-NEXT: %cond = trunc i32 %a30 to i1
; CHECK-NEXT: %wide.chk = and i1 true, %cond
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %wide.chk) [ "deopt"() ]
; CHECK-NEXT: ret void
entry:
call void(i1, ...) @llvm.experimental.guard(i1 true) [ "deopt"() ]
%a1 = mul i32 %a0, %a0
%a2 = mul i32 %a1, %a1
%a3 = mul i32 %a2, %a2
%a4 = mul i32 %a3, %a3
%a5 = mul i32 %a4, %a4
%a6 = mul i32 %a5, %a5
%a7 = mul i32 %a6, %a6
%a8 = mul i32 %a7, %a7
%a9 = mul i32 %a8, %a8
%a10 = mul i32 %a9, %a9
%a11 = mul i32 %a10, %a10
%a12 = mul i32 %a11, %a11
%a13 = mul i32 %a12, %a12
%a14 = mul i32 %a13, %a13
%a15 = mul i32 %a14, %a14
%a16 = mul i32 %a15, %a15
%a17 = mul i32 %a16, %a16
%a18 = mul i32 %a17, %a17
%a19 = mul i32 %a18, %a18
%a20 = mul i32 %a19, %a19
%a21 = mul i32 %a20, %a20
%a22 = mul i32 %a21, %a21
%a23 = mul i32 %a22, %a22
%a24 = mul i32 %a23, %a23
%a25 = mul i32 %a24, %a24
%a26 = mul i32 %a25, %a25
%a27 = mul i32 %a26, %a26
%a28 = mul i32 %a27, %a27
%a29 = mul i32 %a28, %a28
%a30 = mul i32 %a29, %a29
%cond = trunc i32 %a30 to i1
call void(i1, ...) @llvm.experimental.guard(i1 %cond) [ "deopt"() ]
ret void
}
define void @f_13(i32 %a) {
; CHECK-LABEL: @f_13(
entry:
; CHECK: %wide.chk = icmp ult i32 %a, 10
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %wide.chk) [ "deopt"() ]
; CHECK: br i1 undef, label %left, label %right
%cond_0 = icmp ult i32 %a, 14
call void(i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
br i1 undef, label %left, label %right
left:
%cond_1 = icmp slt i32 %a, 10
call void(i1, ...) @llvm.experimental.guard(i1 %cond_1) [ "deopt"() ]
ret void
right:
ret void
}
define void @f_14(i32 %a) {
; CHECK-LABEL: @f_14(
entry:
; CHECK: %cond_0 = icmp ult i32 %a, 14
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
; CHECK: br i1 undef, label %left, label %right
%cond_0 = icmp ult i32 %a, 14
call void(i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
br i1 undef, label %left, label %right
left:
; CHECK: left:
; CHECK: %cond_1 = icmp sgt i32 %a, 10
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %cond_1) [ "deopt"() ]
%cond_1 = icmp sgt i32 %a, 10
call void(i1, ...) @llvm.experimental.guard(i1 %cond_1) [ "deopt"() ]
ret void
right:
ret void
}
; Make sure we do not widen guard by trivial true conditions into something.
define void @f_15(i1 %cond_0, i1 %cond_1) {
; CHECK-LABEL: @f_15(
entry:
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 true) [ "deopt"() ]
; CHECK: ret void
call void(i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
call void(i1, ...) @llvm.experimental.guard(i1 true) [ "deopt"() ]
ret void
}
; Make sure we do not widen guard by trivial false conditions into something.
define void @f_16(i1 %cond_0, i1 %cond_1) {
; CHECK-LABEL: @f_16(
entry:
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 false) [ "deopt"() ]
; CHECK: ret void
call void(i1, ...) @llvm.experimental.guard(i1 %cond_0) [ "deopt"() ]
call void(i1, ...) @llvm.experimental.guard(i1 false) [ "deopt"() ]
ret void
}