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llvm-mirror/test/Transforms/IRCE/conjunctive-checks.ll
Roman Tereshin 91525f438c Revert "[SCEV][NFC] Check NoWrap flags before lexicographical comparison of SCEVs"
This reverts r319889.

Unfortunately, wrapping flags are not a part of SCEV's identity (they
do not participate in computing a hash value or in equality
comparisons) and in fact they could be assigned after the fact w/o
rebuilding a SCEV.

Grep for const_cast's to see quite a few of examples, apparently all
for AddRec's at the moment.

So, if 2 expressions get built in 2 slightly different ways: one with
flags set in the beginning, the other with the flags attached later
on, we may end up with 2 expressions which are exactly the same but
have their operands swapped in one of the commutative N-ary
expressions, and at least one of them will have "sorted by complexity"
invariant broken.

2 identical SCEV's won't compare equal by pointer comparison as they
are supposed to.

A real-world reproducer is added as a regression test: the issue
described causes 2 identical SCEV expressions to have different order
of operands and therefore compare not equal, which in its turn
prevents LoadStoreVectorizer from vectorizing a pair of consecutive
loads.

On a larger example (the source of the test attached, which is a
bugpoint) I have seen even weirder behavior: adding a constant to an
existing SCEV changes the order of the existing terms, for instance,
getAddExpr(1, ((A * B) + (C * D))) returns (1 + (C * D) + (A * B)).

Differential Revision: https://reviews.llvm.org/D40645

llvm-svn: 340777
2018-08-27 21:41:37 +00:00

111 lines
4.0 KiB
LLVM

; RUN: opt -S -verify-loop-info -irce < %s | FileCheck %s
; RUN: opt -S -verify-loop-info -passes='require<branch-prob>,loop(irce)' < %s | FileCheck %s
define void @f_0(i32 *%arr, i32 *%a_len_ptr, i32 %n, i1* %cond_buf) {
; CHECK-LABEL: @f_0(
; CHECK: loop.preheader:
; CHECK: [[not_n:[^ ]+]] = sub i32 -1, %n
; CHECK: [[not_safe_range_end:[^ ]+]] = sub i32 3, %len
; CHECK: [[not_exit_main_loop_at_hiclamp_cmp:[^ ]+]] = icmp sgt i32 [[not_n]], [[not_safe_range_end]]
; CHECK: [[not_exit_main_loop_at_hiclamp:[^ ]+]] = select i1 [[not_exit_main_loop_at_hiclamp_cmp]], i32 [[not_n]], i32 [[not_safe_range_end]]
; CHECK: [[exit_main_loop_at_hiclamp:[^ ]+]] = sub i32 -1, [[not_exit_main_loop_at_hiclamp]]
; CHECK: [[exit_main_loop_at_loclamp_cmp:[^ ]+]] = icmp sgt i32 [[exit_main_loop_at_hiclamp]], 0
; CHECK: [[exit_main_loop_at_loclamp:[^ ]+]] = select i1 [[exit_main_loop_at_loclamp_cmp]], i32 [[exit_main_loop_at_hiclamp]], i32 0
; CHECK: [[enter_main_loop:[^ ]+]] = icmp slt i32 0, [[exit_main_loop_at_loclamp]]
; CHECK: br i1 [[enter_main_loop]], label %loop.preheader2, label %main.pseudo.exit
; CHECK: loop.preheader2:
; CHECK: br label %loop
entry:
%len = load i32, i32* %a_len_ptr, !range !0
%first.itr.check = icmp sgt i32 %n, 0
br i1 %first.itr.check, label %loop, label %exit
loop:
%idx = phi i32 [ 0, %entry ] , [ %idx.next, %in.bounds ]
%idx.next = add i32 %idx, 1
%idx.for.abc = add i32 %idx, 4
%abc.actual = icmp slt i32 %idx.for.abc, %len
%cond = load volatile i1, i1* %cond_buf
%abc = and i1 %cond, %abc.actual
br i1 %abc, label %in.bounds, label %out.of.bounds, !prof !1
; CHECK: loop:
; CHECK: %cond = load volatile i1, i1* %cond_buf
; CHECK: %abc = and i1 %cond, true
; CHECK: br i1 %abc, label %in.bounds, label %out.of.bounds.loopexit3, !prof !1
; CHECK: out.of.bounds.loopexit:
; CHECK: br label %out.of.bounds
in.bounds:
%addr = getelementptr i32, i32* %arr, i32 %idx.for.abc
store i32 0, i32* %addr
%next = icmp slt i32 %idx.next, %n
br i1 %next, label %loop, label %exit
out.of.bounds:
ret void
exit:
ret void
}
define void @f_1(
i32* %arr_a, i32* %a_len_ptr, i32* %arr_b, i32* %b_len_ptr, i32 %n) {
; CHECK-LABEL: @f_1(
; CHECK: loop.preheader:
; CHECK: [[not_len_b:[^ ]+]] = sub i32 -1, %len.b
; CHECK: [[not_len_a:[^ ]+]] = sub i32 -1, %len.a
; CHECK: [[smax_not_len_cond:[^ ]+]] = icmp sgt i32 [[not_len_b]], [[not_len_a]]
; CHECK: [[smax_not_len:[^ ]+]] = select i1 [[smax_not_len_cond]], i32 [[not_len_b]], i32 [[not_len_a]]
; CHECK: [[not_n:[^ ]+]] = sub i32 -1, %n
; CHECK: [[not_upper_limit_cond_loclamp:[^ ]+]] = icmp sgt i32 [[smax_not_len]], [[not_n]]
; CHECK: [[not_upper_limit_loclamp:[^ ]+]] = select i1 [[not_upper_limit_cond_loclamp]], i32 [[smax_not_len]], i32 [[not_n]]
; CHECK: [[upper_limit_loclamp:[^ ]+]] = sub i32 -1, [[not_upper_limit_loclamp]]
; CHECK: [[upper_limit_cmp:[^ ]+]] = icmp sgt i32 [[upper_limit_loclamp]], 0
; CHECK: [[upper_limit:[^ ]+]] = select i1 [[upper_limit_cmp]], i32 [[upper_limit_loclamp]], i32 0
entry:
%len.a = load i32, i32* %a_len_ptr, !range !0
%len.b = load i32, i32* %b_len_ptr, !range !0
%first.itr.check = icmp sgt i32 %n, 0
br i1 %first.itr.check, label %loop, label %exit
loop:
%idx = phi i32 [ 0, %entry ] , [ %idx.next, %in.bounds ]
%idx.next = add i32 %idx, 1
%abc.a = icmp slt i32 %idx, %len.a
%abc.b = icmp slt i32 %idx, %len.b
%abc = and i1 %abc.a, %abc.b
br i1 %abc, label %in.bounds, label %out.of.bounds, !prof !1
; CHECK: loop:
; CHECK: %abc = and i1 true, true
; CHECK: br i1 %abc, label %in.bounds, label %out.of.bounds.loopexit4, !prof !1
; CHECK: out.of.bounds.loopexit:
; CHECK-NEXT: br label %out.of.bounds
in.bounds:
%addr.a = getelementptr i32, i32* %arr_a, i32 %idx
store i32 0, i32* %addr.a
%addr.b = getelementptr i32, i32* %arr_b, i32 %idx
store i32 -1, i32* %addr.b
%next = icmp slt i32 %idx.next, %n
br i1 %next, label %loop, label %exit
out.of.bounds:
ret void
exit:
ret void
}
!0 = !{i32 0, i32 2147483647}
!1 = !{!"branch_weights", i32 64, i32 4}