; RUN: opt -passes='print<scalar-evolution>,loop(simple-loop-unswitch<nontrivial>,loop-instsimplify),print<scalar-evolution>' -S < %s 2>%t.scev | FileCheck %s
; RUN: opt -verify-memoryssa -passes='print<scalar-evolution>,loop-mssa(simple-loop-unswitch<nontrivial>,loop-instsimplify),print<scalar-evolution>' -S < %s 2>%t.scev | FileCheck %s
; RUN: FileCheck %s --check-prefix=SCEV < %t.scev
target triple = "x86_64-unknown-linux-gnu"
declare void @f()
; Check that trivially unswitching an inner loop resets both the inner and outer
; loop trip count.
define void @test1(i32 %n, i32 %m, i1 %cond) {
; Check that SCEV has no trip count before unswitching.
; SCEV-LABEL: Determining loop execution counts for: @test1
; SCEV: Loop %inner_loop_begin: <multiple exits> Unpredictable backedge-taken count.
; SCEV: Loop %outer_loop_begin: Unpredictable backedge-taken count.
;
; Now check that after unswitching and simplifying instructions we get clean
; backedge-taken counts.
; SCEV-LABEL: Determining loop execution counts for: @test1
; SCEV: Loop %inner_loop_begin: backedge-taken count is (-1 + (1 smax %m))<nsw>
; SCEV: Loop %outer_loop_begin: backedge-taken count is (-1 + (1 smax %n))<nsw>
;
; And verify the code matches what we expect.
; CHECK-LABEL: define void @test1(
entry:
br label %outer_loop_begin
; Ensure the outer loop didn't get unswitched.
; CHECK: entry:
; CHECK-NEXT: br label %outer_loop_begin
outer_loop_begin:
%i = phi i32 [ %i.next, %outer_loop_latch ], [ 0, %entry ]
; Block unswitching of the outer loop with a noduplicate call.
call void @f() noduplicate
br label %inner_loop_begin
; Ensure the inner loop got unswitched into the outer loop.
; CHECK: outer_loop_begin:
; CHECK-NEXT: %{{.*}} = phi i32
; CHECK-NEXT: call void @f()
; CHECK-NEXT: br i1 %cond,
inner_loop_begin:
%j = phi i32 [ %j.next, %inner_loop_latch ], [ 0, %outer_loop_begin ]
br i1 %cond, label %inner_loop_latch, label %inner_loop_early_exit
inner_loop_latch:
%j.next = add nsw i32 %j, 1
%j.cmp = icmp slt i32 %j.next, %m
br i1 %j.cmp, label %inner_loop_begin, label %inner_loop_late_exit
inner_loop_early_exit:
%j.lcssa = phi i32 [ %i, %inner_loop_begin ]
br label %outer_loop_latch
inner_loop_late_exit:
br label %outer_loop_latch
outer_loop_latch:
%i.phi = phi i32 [ %j.lcssa, %inner_loop_early_exit ], [ %i, %inner_loop_late_exit ]
%i.next = add nsw i32 %i.phi, 1
%i.cmp = icmp slt i32 %i.next, %n
br i1 %i.cmp, label %outer_loop_begin, label %exit
exit:
ret void
}
; Check that trivially unswitching an inner loop resets both the inner and outer
; loop trip count.
define void @test2(i32 %n, i32 %m, i32 %cond) {
; Check that SCEV has no trip count before unswitching.
; SCEV-LABEL: Determining loop execution counts for: @test2
; SCEV: Loop %inner_loop_begin: <multiple exits> Unpredictable backedge-taken count.
; SCEV: Loop %outer_loop_begin: Unpredictable backedge-taken count.
;
; Now check that after unswitching and simplifying instructions we get clean
; backedge-taken counts.
; SCEV-LABEL: Determining loop execution counts for: @test2
; SCEV: Loop %inner_loop_begin: backedge-taken count is (-1 + (1 smax %m))<nsw>
; SCEV: Loop %outer_loop_begin: backedge-taken count is (-1 + (1 smax %n))<nsw>
;
; CHECK-LABEL: define void @test2(
entry:
br label %outer_loop_begin
; Ensure the outer loop didn't get unswitched.
; CHECK: entry:
; CHECK-NEXT: br label %outer_loop_begin
outer_loop_begin:
%i = phi i32 [ %i.next, %outer_loop_latch ], [ 0, %entry ]
; Block unswitching of the outer loop with a noduplicate call.
call void @f() noduplicate
br label %inner_loop_begin
; Ensure the inner loop got unswitched into the outer loop.
; CHECK: outer_loop_begin:
; CHECK-NEXT: %{{.*}} = phi i32
; CHECK-NEXT: call void @f()
; CHECK-NEXT: switch i32 %cond,
inner_loop_begin:
%j = phi i32 [ %j.next, %inner_loop_latch ], [ 0, %outer_loop_begin ]
switch i32 %cond, label %inner_loop_early_exit [
i32 1, label %inner_loop_latch
i32 2, label %inner_loop_latch
]
inner_loop_latch:
%j.next = add nsw i32 %j, 1
%j.cmp = icmp slt i32 %j.next, %m
br i1 %j.cmp, label %inner_loop_begin, label %inner_loop_late_exit
inner_loop_early_exit:
%j.lcssa = phi i32 [ %i, %inner_loop_begin ]
br label %outer_loop_latch
inner_loop_late_exit:
br label %outer_loop_latch
outer_loop_latch:
%i.phi = phi i32 [ %j.lcssa, %inner_loop_early_exit ], [ %i, %inner_loop_late_exit ]
%i.next = add nsw i32 %i.phi, 1
%i.cmp = icmp slt i32 %i.next, %n
br i1 %i.cmp, label %outer_loop_begin, label %exit
exit:
ret void
}
; Check that non-trivial unswitching of a branch in an inner loop into the outer
; loop invalidates both inner and outer.
define void @test3(i32 %n, i32 %m, i1 %cond) {
; Check that SCEV has no trip count before unswitching.
; SCEV-LABEL: Determining loop execution counts for: @test3
; SCEV: Loop %inner_loop_begin: <multiple exits> Unpredictable backedge-taken count.
; SCEV: Loop %outer_loop_begin: Unpredictable backedge-taken count.
;
; Now check that after unswitching and simplifying instructions we get clean
; backedge-taken counts.
; SCEV-LABEL: Determining loop execution counts for: @test3
; SCEV: Loop %inner_loop_begin{{.*}}: backedge-taken count is (-1 + (1 smax %m))<nsw>
; SCEV: Loop %outer_loop_begin: backedge-taken count is (-1 + (1 smax %n))<nsw>
;
; And verify the code matches what we expect.
; CHECK-LABEL: define void @test3(
entry:
br label %outer_loop_begin
; Ensure the outer loop didn't get unswitched.
; CHECK: entry:
; CHECK-NEXT: br label %outer_loop_begin
outer_loop_begin:
%i = phi i32 [ %i.next, %outer_loop_latch ], [ 0, %entry ]
; Block unswitching of the outer loop with a noduplicate call.
call void @f() noduplicate
br label %inner_loop_begin
; Ensure the inner loop got unswitched into the outer loop.
; CHECK: outer_loop_begin:
; CHECK-NEXT: %{{.*}} = phi i32
; CHECK-NEXT: call void @f()
; CHECK-NEXT: br i1 %cond,
inner_loop_begin:
%j = phi i32 [ %j.next, %inner_loop_latch ], [ 0, %outer_loop_begin ]
%j.tmp = add nsw i32 %j, 1
br i1 %cond, label %inner_loop_latch, label %inner_loop_early_exit
inner_loop_latch:
%j.next = add nsw i32 %j, 1
%j.cmp = icmp slt i32 %j.next, %m
br i1 %j.cmp, label %inner_loop_begin, label %inner_loop_late_exit
inner_loop_early_exit:
%j.lcssa = phi i32 [ %j.tmp, %inner_loop_begin ]
br label %outer_loop_latch
inner_loop_late_exit:
br label %outer_loop_latch
outer_loop_latch:
%inc.phi = phi i32 [ %j.lcssa, %inner_loop_early_exit ], [ 1, %inner_loop_late_exit ]
%i.next = add nsw i32 %i, %inc.phi
%i.cmp = icmp slt i32 %i.next, %n
br i1 %i.cmp, label %outer_loop_begin, label %exit
exit:
ret void
}
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