[Test] Add some tests showing room for optimization exploiting undef and UB

This commit is contained in:
Max Kazantsev 2021-06-21 13:11:15 +07:00
parent e37653da13
commit 3f2ff7cc8c
1 changed files with 222 additions and 0 deletions

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@ -731,6 +731,228 @@ failure:
unreachable unreachable
} }
; TODO: We can break the backedge here by assuming that undef = sub.
define i32 @test_multiple_pred_undef_1() {
; CHECK-LABEL: @test_multiple_pred_undef_1(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[SUM:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[SUM_NEXT:%.*]], [[BACKEDGE:%.*]] ]
; CHECK-NEXT: [[SUB:%.*]] = sub i32 4, [[SUM]]
; CHECK-NEXT: [[IS_POSITIVE:%.*]] = icmp sgt i32 [[SUB]], 0
; CHECK-NEXT: br i1 [[IS_POSITIVE]], label [[IF_TRUE:%.*]], label [[IF_FALSE:%.*]]
; CHECK: if.true:
; CHECK-NEXT: br i1 undef, label [[IF_TRUE_1:%.*]], label [[IF_TRUE_2:%.*]]
; CHECK: if.true.1:
; CHECK-NEXT: br label [[BACKEDGE]]
; CHECK: if.true.2:
; CHECK-NEXT: br label [[BACKEDGE]]
; CHECK: if.false:
; CHECK-NEXT: br i1 undef, label [[IF_FALSE_1:%.*]], label [[IF_FALSE_2:%.*]]
; CHECK: if.false.1:
; CHECK-NEXT: br label [[BACKEDGE]]
; CHECK: if.false.2:
; CHECK-NEXT: br label [[BACKEDGE]]
; CHECK: backedge:
; CHECK-NEXT: [[MERGE_PHI:%.*]] = phi i32 [ 0, [[IF_FALSE_1]] ], [ 0, [[IF_FALSE_2]] ], [ [[SUB]], [[IF_TRUE_1]] ], [ undef, [[IF_TRUE_2]] ]
; CHECK-NEXT: [[SUM_NEXT]] = add i32 [[SUM]], [[MERGE_PHI]]
; CHECK-NEXT: [[LOOP_COND:%.*]] = icmp ne i32 [[SUM_NEXT]], 4
; CHECK-NEXT: br i1 [[LOOP_COND]], label [[LOOP]], label [[DONE:%.*]]
; CHECK: done:
; CHECK-NEXT: [[SUM_NEXT_LCSSA:%.*]] = phi i32 [ [[SUM_NEXT]], [[BACKEDGE]] ]
; CHECK-NEXT: ret i32 [[SUM_NEXT_LCSSA]]
; CHECK: failure:
; CHECK-NEXT: unreachable
;
entry:
br label %loop
loop: ; preds = %backedge, %entry
%sum = phi i32 [ 0, %entry ], [ %sum.next, %backedge ]
%sub = sub i32 4, %sum
%is.positive = icmp sgt i32 %sub, 0
br i1 %is.positive, label %if.true, label %if.false
if.true:
br i1 undef, label %if.true.1, label %if.true.2
if.true.1:
br label %backedge
if.true.2:
br label %backedge
if.false: ; preds = %loop
br i1 undef, label %if.false.1, label %if.false.2
if.false.1:
br label %backedge
if.false.2:
br label %backedge
backedge:
%merge.phi = phi i32 [ 0, %if.false.1 ], [ 0, %if.false.2 ], [ %sub, %if.true.1 ], [ undef, %if.true.2 ]
%sum.next = add i32 %sum, %merge.phi
%loop.cond = icmp ne i32 %sum.next, 4
br i1 %loop.cond, label %loop, label %done
done: ; preds = %backedge
%sum.next.lcssa = phi i32 [ %sum.next, %backedge ]
ret i32 %sum.next.lcssa
failure:
unreachable
}
; TODO: We can break the backedge here by assuming that undef = sub.
define i32 @test_multiple_pred_undef_2() {
; CHECK-LABEL: @test_multiple_pred_undef_2(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[SUM:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[SUM_NEXT:%.*]], [[BACKEDGE:%.*]] ]
; CHECK-NEXT: [[SUB:%.*]] = sub i32 4, [[SUM]]
; CHECK-NEXT: [[IS_POSITIVE:%.*]] = icmp sgt i32 [[SUB]], 0
; CHECK-NEXT: br i1 [[IS_POSITIVE]], label [[IF_TRUE:%.*]], label [[IF_FALSE:%.*]]
; CHECK: if.true:
; CHECK-NEXT: br i1 undef, label [[IF_TRUE_1:%.*]], label [[IF_TRUE_2:%.*]]
; CHECK: if.true.1:
; CHECK-NEXT: br label [[BACKEDGE]]
; CHECK: if.true.2:
; CHECK-NEXT: br label [[BACKEDGE]]
; CHECK: if.false:
; CHECK-NEXT: br i1 undef, label [[IF_FALSE_1:%.*]], label [[IF_FALSE_2:%.*]]
; CHECK: if.false.1:
; CHECK-NEXT: br label [[BACKEDGE]]
; CHECK: if.false.2:
; CHECK-NEXT: br label [[BACKEDGE]]
; CHECK: backedge:
; CHECK-NEXT: [[MERGE_PHI:%.*]] = phi i32 [ 0, [[IF_FALSE_1]] ], [ 0, [[IF_FALSE_2]] ], [ undef, [[IF_TRUE_1]] ], [ [[SUB]], [[IF_TRUE_2]] ]
; CHECK-NEXT: [[SUM_NEXT]] = add i32 [[SUM]], [[MERGE_PHI]]
; CHECK-NEXT: [[LOOP_COND:%.*]] = icmp ne i32 [[SUM_NEXT]], 4
; CHECK-NEXT: br i1 [[LOOP_COND]], label [[LOOP]], label [[DONE:%.*]]
; CHECK: done:
; CHECK-NEXT: [[SUM_NEXT_LCSSA:%.*]] = phi i32 [ [[SUM_NEXT]], [[BACKEDGE]] ]
; CHECK-NEXT: ret i32 [[SUM_NEXT_LCSSA]]
; CHECK: failure:
; CHECK-NEXT: unreachable
;
entry:
br label %loop
loop: ; preds = %backedge, %entry
%sum = phi i32 [ 0, %entry ], [ %sum.next, %backedge ]
%sub = sub i32 4, %sum
%is.positive = icmp sgt i32 %sub, 0
br i1 %is.positive, label %if.true, label %if.false
if.true:
br i1 undef, label %if.true.1, label %if.true.2
if.true.1:
br label %backedge
if.true.2:
br label %backedge
if.false: ; preds = %loop
br i1 undef, label %if.false.1, label %if.false.2
if.false.1:
br label %backedge
if.false.2:
br label %backedge
backedge:
%merge.phi = phi i32 [ 0, %if.false.1 ], [ 0, %if.false.2 ], [ undef, %if.true.1 ], [ %sub, %if.true.2 ]
%sum.next = add i32 %sum, %merge.phi
%loop.cond = icmp ne i32 %sum.next, 4
br i1 %loop.cond, label %loop, label %done
done: ; preds = %backedge
%sum.next.lcssa = phi i32 [ %sum.next, %backedge ]
ret i32 %sum.next.lcssa
failure:
unreachable
}
; TODO: We can break the backedge here by exploiting undef.
define i32 @test_multiple_pred_undef_3() {
; CHECK-LABEL: @test_multiple_pred_undef_3(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[SUM:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[SUM_NEXT:%.*]], [[BACKEDGE:%.*]] ]
; CHECK-NEXT: [[SUB:%.*]] = sub i32 4, [[SUM]]
; CHECK-NEXT: [[IS_POSITIVE:%.*]] = icmp sgt i32 [[SUB]], 0
; CHECK-NEXT: br i1 [[IS_POSITIVE]], label [[IF_TRUE:%.*]], label [[IF_FALSE:%.*]]
; CHECK: if.true:
; CHECK-NEXT: br i1 undef, label [[IF_TRUE_1:%.*]], label [[IF_TRUE_2:%.*]]
; CHECK: if.true.1:
; CHECK-NEXT: br label [[BACKEDGE]]
; CHECK: if.true.2:
; CHECK-NEXT: br label [[BACKEDGE]]
; CHECK: if.false:
; CHECK-NEXT: br i1 undef, label [[IF_FALSE_1:%.*]], label [[IF_FALSE_2:%.*]]
; CHECK: if.false.1:
; CHECK-NEXT: br label [[BACKEDGE]]
; CHECK: if.false.2:
; CHECK-NEXT: br label [[BACKEDGE]]
; CHECK: backedge:
; CHECK-NEXT: [[MERGE_PHI:%.*]] = phi i32 [ 0, [[IF_FALSE_1]] ], [ 0, [[IF_FALSE_2]] ], [ undef, [[IF_TRUE_1]] ], [ undef, [[IF_TRUE_2]] ]
; CHECK-NEXT: [[SUM_NEXT]] = add i32 [[SUM]], [[MERGE_PHI]]
; CHECK-NEXT: [[LOOP_COND:%.*]] = icmp ne i32 [[SUM_NEXT]], 4
; CHECK-NEXT: br i1 [[LOOP_COND]], label [[LOOP]], label [[DONE:%.*]]
; CHECK: done:
; CHECK-NEXT: [[SUM_NEXT_LCSSA:%.*]] = phi i32 [ [[SUM_NEXT]], [[BACKEDGE]] ]
; CHECK-NEXT: ret i32 [[SUM_NEXT_LCSSA]]
; CHECK: failure:
; CHECK-NEXT: unreachable
;
entry:
br label %loop
loop: ; preds = %backedge, %entry
%sum = phi i32 [ 0, %entry ], [ %sum.next, %backedge ]
%sub = sub i32 4, %sum
%is.positive = icmp sgt i32 %sub, 0
br i1 %is.positive, label %if.true, label %if.false
if.true:
br i1 undef, label %if.true.1, label %if.true.2
if.true.1:
br label %backedge
if.true.2:
br label %backedge
if.false: ; preds = %loop
br i1 undef, label %if.false.1, label %if.false.2
if.false.1:
br label %backedge
if.false.2:
br label %backedge
backedge:
%merge.phi = phi i32 [ 0, %if.false.1 ], [ 0, %if.false.2 ], [ undef, %if.true.1 ], [ undef, %if.true.2 ]
%sum.next = add i32 %sum, %merge.phi
%loop.cond = icmp ne i32 %sum.next, 4
br i1 %loop.cond, label %loop, label %done
done: ; preds = %backedge
%sum.next.lcssa = phi i32 [ %sum.next, %backedge ]
ret i32 %sum.next.lcssa
failure:
unreachable
}
; TODO: We can break the backedge here. ; TODO: We can break the backedge here.
define i32 @test_select(i32 %limit) { define i32 @test_select(i32 %limit) {
; CHECK-LABEL: @test_select( ; CHECK-LABEL: @test_select(