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llvm-mirror/test/Transforms/IRCE/empty_ranges.ll
Fedor Sergeev 3a27395ee7 [New PM][IRCE] port of Inductive Range Check Elimination pass to the new pass manager
There are two nontrivial details here:
* Loop structure update interface is quite different with new pass manager,
  so the code to add new loops was factored out

* BranchProbabilityInfo is not a loop analysis, so it can not be just getResult'ed from
  within the loop pass. It cant even be queried through getCachedResult as LoopCanonicalization
  sequence (e.g. LoopSimplify) might invalidate BPI results.

  Complete solution for BPI will likely take some time to discuss and figure out,
  so for now this was partially solved by making BPI optional in IRCE
  (skipping a couple of profitability checks if it is absent).

Most of the IRCE tests got their corresponding new-pass-manager variant enabled.
Only two of them depend on BPI, both marked with TODO, to be turned on when BPI
starts being available for loop passes.

Reviewers: chandlerc, mkazantsev, sanjoy, asbirlea
Reviewed By: mkazantsev
Differential Revision: https://reviews.llvm.org/D43795

llvm-svn: 327619
2018-03-15 11:01:19 +00:00

70 lines
2.4 KiB
LLVM

; RUN: opt -verify-loop-info -irce-print-changed-loops -irce -S
; RUN: opt -verify-loop-info -irce-print-changed-loops -passes='require<branch-prob>,loop(irce)' -S
; Make sure that IRCE doesn't apply in case of empty ranges.
; (i + 30 < 40) if i in [-30, 10).
; Intersected with iteration space, it is [0, 10).
; (i - 60 < 40) if i in [60 , 100).
; The intersection with safe iteration space is the empty range [60, 10).
; It is better to eliminate one range check than attempt to eliminate both given
; that we will never go to the main loop in the latter case and basically
; only duplicate code with no benefits.
define void @test_01(i32* %arr, i32* %a_len_ptr) #0 {
; CHECK-LABEL: test_01(
; CHECK-NOT: preloop
; CHECK: entry:
; CHECK-NEXT: br i1 true, label %loop.preheader, label %main.pseudo.exit
; CHECK: in.bounds.1:
; CHECK-NEXT: %addr = getelementptr i32, i32* %arr, i32 %idx
; CHECK-NEXT: store i32 0, i32* %addr
; CHECK-NEXT: %off1 = add i32 %idx, 30
; CHECK-NEXT: %c2 = icmp slt i32 %off1, 40
; CHECK-NEXT: br i1 true, label %in.bounds.2, label %exit.loopexit2
; CHECK: in.bounds.2:
; CHECK-NEXT: %off2 = add i32 %idx, -60
; CHECK-NEXT: %c3 = icmp slt i32 %off2, 40
; CHECK-NEXT: br i1 %c3, label %in.bounds.3, label %exit.loopexit2
; CHECK: in.bounds.3:
; CHECK-NEXT: %next = icmp ult i32 %idx.next, 100
; CHECK-NEXT: [[COND1:%[^ ]+]] = icmp ult i32 %idx.next, 10
; CHECK-NEXT: br i1 [[COND1]], label %loop, label %main.exit.selector
; CHECK: main.exit.selector:
; CHECK-NEXT: %idx.next.lcssa = phi i32 [ %idx.next, %in.bounds.3 ]
; CHECK-NEXT: [[COND2:%[^ ]+]] = icmp ult i32 %idx.next.lcssa, 100
; CHECK-NEXT: br i1 [[COND2]], label %main.pseudo.exit, label %exit
; CHECK: postloop:
entry:
br label %loop
loop:
%idx = phi i32 [ 0, %entry ], [ %idx.next, %in.bounds.3 ]
%idx.next = add nsw nuw i32 %idx, 1
%c1 = icmp slt i32 %idx, 20
br i1 %c1, label %in.bounds.1, label %out.of.bounds
in.bounds.1:
%addr = getelementptr i32, i32* %arr, i32 %idx
store i32 0, i32* %addr
%off1 = add i32 %idx, 30
%c2 = icmp slt i32 %off1, 40
br i1 %c2, label %in.bounds.2, label %exit
in.bounds.2:
%off2 = add i32 %idx, -60
%c3 = icmp slt i32 %off2, 40
br i1 %c3, label %in.bounds.3, label %exit
in.bounds.3:
%next = icmp ult i32 %idx.next, 100
br i1 %next, label %loop, label %exit
out.of.bounds:
ret void
exit:
ret void
}