Files
llvm/test/Transforms/IRCE/pre_post_loops.ll
Max Kazantsev a9a5cb971f [IRCE] Fix corner case with Start = INT_MAX
When iterating through loop

  for (int i = INT_MAX; i > 0; i--)

We fail to generate the pre-loop for it. It happens because we use the
overflown value in a comparison predicate when identifying whether or not
we need it.

In old logic, we used SLE predicate against Greatest value which exceeds all
seen values of the IV and might be overflown. Now we use the GreatestSeen
value of this IV with SLT predicate.

Also added a test that ensures that a pre-loop is generated for such loops.

Differential Revision: https://reviews.llvm.org/D35347


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@308001 91177308-0d34-0410-b5e6-96231b3b80d8
2017-07-14 06:35:03 +00:00

118 lines
4.6 KiB
LLVM

; RUN: opt -verify-loop-info -irce-print-changed-loops -irce -S < %s 2>&1 | FileCheck %s
; CHECK: irce: in function test_01: constrained Loop at depth 1 containing: %loop<header><exiting>,%in.bounds<latch><exiting>
; CHECK: irce: in function test_02: constrained Loop at depth 1 containing: %loop<header><exiting>,%in.bounds<latch><exiting>
; Iterate from 0 to SINT_MAX, check that the post-loop is generated.
define void @test_01(i32* %arr, i32* %a_len_ptr) {
; CHECK: test_01(
; CHECK: entry:
; CHECK-NEXT: %exit.mainloop.at = load i32, i32* %a_len_ptr
; CHECK: loop:
; CHECK-NEXT: %idx = phi i32 [ %idx.next, %in.bounds ], [ 0, %loop.preheader ]
; CHECK-NEXT: %idx.next = add i32 %idx, 1
; CHECK-NEXT: %abc = icmp slt i32 %idx, %exit.mainloop.at
; CHECK-NEXT: br i1 true, label %in.bounds,
; CHECK: in.bounds:
; CHECK-NEXT: %addr = getelementptr i32, i32* %arr, i32 %idx
; CHECK-NEXT: store i32 0, i32* %addr
; CHECK-NEXT: %next = icmp slt i32 %idx.next, 2147483647
; CHECK-NEXT: [[COND:%[^ ]+]] = icmp slt i32 %idx.next, %exit.mainloop.at
; CHECK-NEXT: br i1 [[COND]], label %loop, label %main.exit.selector
; CHECK: main.pseudo.exit:
; CHECK-NEXT: %idx.copy = phi i32 [ 0, %entry ], [ %idx.next.lcssa, %main.exit.selector ]
; CHECK-NEXT: %indvar.end = phi i32 [ 0, %entry ], [ %idx.next.lcssa, %main.exit.selector ]
; CHECK-NEXT: br label %postloop
; CHECK: postloop:
; CHECK-NEXT: br label %loop.postloop
; CHECK: loop.postloop:
; CHECK-NEXT: %idx.postloop = phi i32 [ %idx.copy, %postloop ], [ %idx.next.postloop, %in.bounds.postloop ]
; CHECK-NEXT: %idx.next.postloop = add i32 %idx.postloop, 1
; CHECK-NEXT: %abc.postloop = icmp slt i32 %idx.postloop, %exit.mainloop.at
; CHECK-NEXT: br i1 %abc.postloop, label %in.bounds.postloop, label %out.of.bounds.loopexit
; CHECK: in.bounds.postloop:
; CHECK-NEXT: %addr.postloop = getelementptr i32, i32* %arr, i32 %idx.postloop
; CHECK-NEXT: store i32 0, i32* %addr.postloop
; CHECK-NEXT: %next.postloop = icmp slt i32 %idx.next.postloop, 2147483647
; CHECK-NEXT: br i1 %next.postloop, label %loop.postloop, label %exit.loopexit
entry:
%len = load i32, i32* %a_len_ptr, !range !0
br label %loop
loop:
%idx = phi i32 [ 0, %entry ], [ %idx.next, %in.bounds ]
%idx.next = add i32 %idx, 1
%abc = icmp slt i32 %idx, %len
br i1 %abc, label %in.bounds, label %out.of.bounds
in.bounds:
%addr = getelementptr i32, i32* %arr, i32 %idx
store i32 0, i32* %addr
%next = icmp slt i32 %idx.next, 2147483647
br i1 %next, label %loop, label %exit
out.of.bounds:
ret void
exit:
ret void
}
; Iterate from SINT_MAX to 0, check that the pre-loop is generated.
define void @test_02(i32* %arr, i32* %a_len_ptr) {
; CHECK: test_02(
; CHECK: entry:
; CHECK-NEXT: %len = load i32, i32* %a_len_ptr, !range !0
; CHECH-NEXT: br i1 true, label %loop.preloop.preheader
; CHECK: mainloop:
; CHECK-NEXT: br label %loop
; CHECK: loop:
; CHECK-NEXT: %idx = phi i32 [ %idx.preloop.copy, %mainloop ], [ %idx.next, %in.bounds ]
; CHECK-NEXT: %idx.next = add i32 %idx, -1
; CHECK-NEXT: %abc = icmp slt i32 %idx, %len
; CHECK-NEXT: br i1 true, label %in.bounds
; CHECK: in.bounds:
; CHECK-NEXT: %addr = getelementptr i32, i32* %arr, i32 %idx
; CHECK-NEXT: store i32 0, i32* %addr
; CHECK-NEXT: %next = icmp sgt i32 %idx.next, -1
; CHECK-NEXT: br i1 %next, label %loop, label %exit.loopexit
; CHECK: loop.preloop:
; CHECK-NEXT: %idx.preloop = phi i32 [ %idx.next.preloop, %in.bounds.preloop ], [ 2147483647, %loop.preloop.preheader ]
; CHECK-NEXT: %idx.next.preloop = add i32 %idx.preloop, -1
; CHECK-NEXT: %abc.preloop = icmp slt i32 %idx.preloop, %len
; CHECK-NEXT: br i1 %abc.preloop, label %in.bounds.preloop, label %out.of.bounds.loopexit
; CHECK: in.bounds.preloop:
; CHECK-NEXT: %addr.preloop = getelementptr i32, i32* %arr, i32 %idx.preloop
; CHECK-NEXT: store i32 0, i32* %addr.preloop
; CHECK-NEXT: %next.preloop = icmp sgt i32 %idx.next.preloop, -1
; CHECK-NEXT: [[COND:%[^ ]+]] = icmp sgt i32 %idx.next.preloop, -1
; CHECK-NEXT: br i1 [[COND]], label %loop.preloop, label %preloop.exit.selector
entry:
%len = load i32, i32* %a_len_ptr, !range !0
br label %loop
loop:
%idx = phi i32 [ 2147483647, %entry ], [ %idx.next, %in.bounds ]
%idx.next = add i32 %idx, -1
%abc = icmp slt i32 %idx, %len
br i1 %abc, label %in.bounds, label %out.of.bounds
in.bounds:
%addr = getelementptr i32, i32* %arr, i32 %idx
store i32 0, i32* %addr
%next = icmp sgt i32 %idx.next, -1
br i1 %next, label %loop, label %exit
out.of.bounds:
ret void
exit:
ret void
}
!0 = !{i32 0, i32 50}