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clang-p2996/llvm/test/Transforms/IRCE/range_intersect_miscompile.ll
Roman Lebedev b46c085d2b [NFCI] SCEVExpander: emit intrinsics for integral {u,s}{min,max} SCEV expressions 
These intrinsics, not the icmp+select are the canonical form nowadays,
so we might as well directly emit them.

This should not cause any regressions, but if it does,
then then they would needed to be fixed regardless.

Note that this doesn't deal with `SCEVExpander::isHighCostExpansion()`,
but that is a pessimization, not a correctness issue.

Additionally, the non-intrinsic form has issues with undef,
see https://reviews.llvm.org/D88287#2587863
2021-03-06 21:52:46 +03:00

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; RUN: opt -verify-loop-info -irce-print-changed-loops -irce -S < %s 2>&1 | FileCheck %s
; RUN: opt -verify-loop-info -irce-print-changed-loops -passes='require<branch-prob>,irce' -S < %s 2>&1 | FileCheck %s
; CHECK-LABEL: irce: in function test_01: constrained Loop at depth 1 containing:
; CHECK-LABEL: irce: in function test_02: constrained Loop at depth 1 containing:
; CHECK-LABEL: irce: in function test_03: constrained Loop at depth 1 containing:
; CHECK-LABEL: irce: in function test_04: constrained Loop at depth 1 containing:
; CHECK-LABEL: irce: in function test_05: constrained Loop at depth 1 containing:
; This test used to demonstrate a miscompile: the outer loop's IV iterates in
; range of [2, 400) and the range check is done against value 331. Due to a bug
; in range intersection IRCE manages to eliminate the range check without
; inserting a postloop, which is incorrect. We treat the range of this test as
; an unsigned range and are able to intersect ranges correctly and insert a
; postloop.
define void @test_01() {
; CHECK-LABEL: test_01
; CHECK-NOT: preloop
; CHECK: range_check_block: ; preds = %inner_loop
; CHECK-NEXT: %range_check = icmp slt i32 %iv, 331
; CHECK-NEXT: br i1 true, label %loop_latch
; CHECK: loop_latch:
; CHECK-NEXT: %iv_next = add i32 %iv, 1
; CHECK-NEXT: %loop_cond = icmp ult i32 %iv_next, 400
; CHECK-NEXT: [[COND:%[^ ]+]] = icmp ult i32 %iv_next, 331
; CHECK-NEXT: br i1 [[COND]], label %loop_header, label %main.exit.selector
; CHECK: main.exit.selector: ; preds = %loop_latch
; CHECK-NEXT: %iv_next.lcssa = phi i32 [ %iv_next, %loop_latch ]
; CHECK-NEXT: %iv.lcssa = phi i32 [ %iv, %loop_latch ]
; CHECK-NEXT: [[MES_COND:%[^ ]+]] = icmp ult i32 %iv_next.lcssa, 400
; CHECK-NEXT: br i1 [[MES_COND]], label %main.pseudo.exit, label %exit
; CHECK: loop_latch.postloop: ; preds = %range_check_block.postloop
; CHECK-NEXT: %iv_next.postloop = add i32 %iv.postloop, 1
; CHECK-NEXT: %loop_cond.postloop = icmp ult i32 %iv_next.postloop, 400
; CHECK-NEXT: br i1 %loop_cond.postloop, label %loop_header.postloop, label %exit.loopexit
entry:
br label %loop_header
loop_header: ; preds = %loop_latch, %entry
%iv = phi i32 [ 2, %entry ], [ %iv_next, %loop_latch ]
%iv.prev = phi i32 [ 1, %entry ], [ %iv, %loop_latch ]
%tmp2 = icmp sgt i32 %iv.prev, -1
br i1 %tmp2, label %loop_header.split.us, label %exit
loop_header.split.us: ; preds = %loop_header
br label %inner_loop
inner_loop: ; preds = %inner_loop, %loop_header.split.us
%inner_iv = phi i32 [ 1, %loop_header.split.us ], [ %inner_iv_next, %inner_loop ]
%inner_iv_next = add nuw nsw i32 %inner_iv, 1
%inner_cond = icmp ult i32 %inner_iv_next, 31
br i1 %inner_cond, label %inner_loop, label %range_check_block
exit: ; preds = %loop_latch, %loop_header
ret void
range_check_block: ; preds = %inner_loop
%range_check = icmp slt i32 %iv, 331
br i1 %range_check, label %loop_latch, label %deopt
loop_latch: ; preds = %range_check_block
%iv_next = add i32 %iv, 1
%loop_cond = icmp ult i32 %iv_next, 400
br i1 %loop_cond, label %loop_header, label %exit
deopt: ; preds = %range_check_block
ret void
}
; Similar to test_01, but here the range check is done against 450. No postloop
; is required.
define void @test_02() {
; CHECK-LABEL: test_02
; CHECK-NOT: preloop
; CHECK-NOT: postloop
; CHECK: range_check_block: ; preds = %inner_loop
; CHECK-NEXT: %range_check = icmp slt i32 %iv, 450
; CHECK-NEXT: br i1 true, label %loop_latch
; CHECK: loop_latch: ; preds = %range_check_block
; CHECK-NEXT: %iv_next = add i32 %iv, 1
; CHECK-NEXT: %loop_cond = icmp ult i32 %iv_next, 400
; CHECK-NEXT: br i1 %loop_cond, label %loop_header, label %exit
entry:
br label %loop_header
loop_header: ; preds = %loop_latch, %entry
%iv = phi i32 [ 2, %entry ], [ %iv_next, %loop_latch ]
%iv.prev = phi i32 [ 1, %entry ], [ %iv, %loop_latch ]
%tmp2 = icmp sgt i32 %iv.prev, -1
br i1 %tmp2, label %loop_header.split.us, label %exit
loop_header.split.us: ; preds = %loop_header
br label %inner_loop
inner_loop: ; preds = %inner_loop, %loop_header.split.us
%inner_iv = phi i32 [ 1, %loop_header.split.us ], [ %inner_iv_next, %inner_loop ]
%inner_iv_next = add nuw nsw i32 %inner_iv, 1
%inner_cond = icmp ult i32 %inner_iv_next, 31
br i1 %inner_cond, label %inner_loop, label %range_check_block
exit: ; preds = %loop_latch, %loop_header
ret void
range_check_block: ; preds = %inner_loop
%range_check = icmp slt i32 %iv, 450
br i1 %range_check, label %loop_latch, label %deopt
loop_latch: ; preds = %range_check_block
%iv_next = add i32 %iv, 1
%loop_cond = icmp ult i32 %iv_next, 400
br i1 %loop_cond, label %loop_header, label %exit
deopt: ; preds = %range_check_block
ret void
}
; Range check is made against 0, so the safe iteration range is empty. IRCE
; should not apply to the inner loop. The condition %tmp2 can be eliminated.
define void @test_03() {
; CHECK-LABEL: test_03
; CHECK-NOT: preloop
; CHECK-NOT: postloop
; CHECK: %tmp2 = icmp sgt i32 %iv.prev, -1
; CHECK-NEXT: br i1 true, label %loop_header.split.us, label %exit
; CHECK: range_check_block:
; CHECK-NEXT: %range_check = icmp slt i32 %iv, 0
; CHECK-NEXT: br i1 %range_check, label %loop_latch, label %deopt
entry:
br label %loop_header
loop_header: ; preds = %loop_latch, %entry
%iv = phi i32 [ 2, %entry ], [ %iv_next, %loop_latch ]
%iv.prev = phi i32 [ 1, %entry ], [ %iv, %loop_latch ]
%tmp2 = icmp sgt i32 %iv.prev, -1
br i1 %tmp2, label %loop_header.split.us, label %exit
loop_header.split.us: ; preds = %loop_header
br label %inner_loop
inner_loop: ; preds = %inner_loop, %loop_header.split.us
%inner_iv = phi i32 [ 1, %loop_header.split.us ], [ %inner_iv_next, %inner_loop ]
%inner_iv_next = add nuw nsw i32 %inner_iv, 1
%inner_cond = icmp ult i32 %inner_iv_next, 31
br i1 %inner_cond, label %inner_loop, label %range_check_block
exit: ; preds = %loop_latch, %loop_header
ret void
range_check_block: ; preds = %inner_loop
%range_check = icmp slt i32 %iv, 0
br i1 %range_check, label %loop_latch, label %deopt
loop_latch: ; preds = %range_check_block
%iv_next = add i32 %iv, 1
%loop_cond = icmp ult i32 %iv_next, 400
br i1 %loop_cond, label %loop_header, label %exit
deopt: ; preds = %range_check_block
ret void
}
; We can also properly eliminate range check against %n which is not always
; known positive.
define void @test_04(i32* %p) {
; CHECK-LABEL: test_04
; CHECK: entry
; CHECK-NOT: preloop
; CHECK: %tmp2 = icmp sgt i32 %iv.prev, -1
; CHECK-NEXT: br i1 true, label %loop_header.split.us, label %exit
; CHECK: range_check_block:
; CHECK-NEXT: %range_check = icmp slt i32 %iv, %n
; CHECK-NEXT: br i1 true, label %loop_latch, label %deopt
; CHECK: postloop:
entry:
%n = load i32, i32* %p
br label %loop_header
loop_header: ; preds = %loop_latch, %entry
%iv = phi i32 [ 2, %entry ], [ %iv_next, %loop_latch ]
%iv.prev = phi i32 [ 1, %entry ], [ %iv, %loop_latch ]
%tmp2 = icmp sgt i32 %iv.prev, -1
br i1 %tmp2, label %loop_header.split.us, label %exit
loop_header.split.us: ; preds = %loop_header
br label %inner_loop
inner_loop: ; preds = %inner_loop, %loop_header.split.us
%inner_iv = phi i32 [ 1, %loop_header.split.us ], [ %inner_iv_next, %inner_loop ]
%inner_iv_next = add nuw nsw i32 %inner_iv, 1
%inner_cond = icmp ult i32 %inner_iv_next, 31
br i1 %inner_cond, label %inner_loop, label %range_check_block
exit: ; preds = %loop_latch, %loop_header
ret void
range_check_block: ; preds = %inner_loop
%range_check = icmp slt i32 %iv, %n
br i1 %range_check, label %loop_latch, label %deopt
loop_latch: ; preds = %range_check_block
%iv_next = add i32 %iv, 1
%loop_cond = icmp ult i32 %iv_next, 400
br i1 %loop_cond, label %loop_header, label %exit
deopt: ; preds = %range_check_block
ret void
}
; Same as test_04, but range guarantees that %n is positive. So we can safely
; intersect ranges (with insertion of postloop).
define void @test_05(i32* %p) {
; CHECK-LABEL: test_05
; CHECK-NOT: preloop
; CHECK: entry:
; CHECK-NEXT: %n = load i32, i32* %p, align 4, !range !
; CHECK-NEXT: %exit.mainloop.at = call i32 @llvm.umax.i32(i32 %n, i32 2)
; CHECK-NEXT: [[CMP_2:%[^ ]+]] = icmp ult i32 2, %exit.mainloop.at
; CHECK-NEXT: br i1 [[CMP_2]], label %loop_header.preheader, label %main.pseudo.exit
; CHECK: range_check_block: ; preds = %inner_loop
; CHECK-NEXT: %range_check = icmp slt i32 %iv, %n
; CHECK-NEXT: br i1 true, label %loop_latch, label %deopt.loopexit2
; CHECK: loop_latch: ; preds = %range_check_block
; CHECK-NEXT: %iv_next = add i32 %iv, 1
; CHECK-NEXT: %loop_cond = icmp ult i32 %iv_next, 400
; CHECK-NEXT: [[COND:%[^ ]+]] = icmp ult i32 %iv_next, %exit.mainloop.at
; CHECK-NEXT: br i1 [[COND]], label %loop_header, label %main.exit.selector
; CHECK: main.exit.selector: ; preds = %loop_latch
; CHECK-NEXT: %iv_next.lcssa = phi i32 [ %iv_next, %loop_latch ]
; CHECK-NEXT: %iv.lcssa = phi i32 [ %iv, %loop_latch ]
; CHECK-NEXT: [[MES_COND:%[^ ]+]] = icmp ult i32 %iv_next.lcssa, 400
; CHECK-NEXT: br i1 [[MES_COND]], label %main.pseudo.exit, label %exit
; CHECK: loop_latch.postloop: ; preds = %range_check_block.postloop
; CHECK-NEXT: %iv_next.postloop = add i32 %iv.postloop, 1
; CHECK-NEXT: %loop_cond.postloop = icmp ult i32 %iv_next.postloop, 400
; CHECK-NEXT: br i1 %loop_cond.postloop, label %loop_header.postloop, label %exit.loopexit
entry:
%n = load i32, i32* %p, !range !0
br label %loop_header
loop_header: ; preds = %loop_latch, %entry
%iv = phi i32 [ 2, %entry ], [ %iv_next, %loop_latch ]
%iv.prev = phi i32 [ 1, %entry ], [ %iv, %loop_latch ]
%tmp2 = icmp sgt i32 %iv.prev, -1
br i1 %tmp2, label %loop_header.split.us, label %exit
loop_header.split.us: ; preds = %loop_header
br label %inner_loop
inner_loop: ; preds = %inner_loop, %loop_header.split.us
%inner_iv = phi i32 [ 1, %loop_header.split.us ], [ %inner_iv_next, %inner_loop ]
%inner_iv_next = add nuw nsw i32 %inner_iv, 1
%inner_cond = icmp ult i32 %inner_iv_next, 31
br i1 %inner_cond, label %inner_loop, label %range_check_block
exit: ; preds = %loop_latch, %loop_header
ret void
range_check_block: ; preds = %inner_loop
%range_check = icmp slt i32 %iv, %n
br i1 %range_check, label %loop_latch, label %deopt
loop_latch: ; preds = %range_check_block
%iv_next = add i32 %iv, 1
%loop_cond = icmp ult i32 %iv_next, 400
br i1 %loop_cond, label %loop_header, label %exit
deopt: ; preds = %range_check_block
ret void
}
!0 = !{i32 0, i32 50}
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