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clang-p2996/llvm/test/Transforms/UnifyLoopExits/integer_guards.ll
Brendon Cahoon f59205aef9 [BasicBlockUtils] Add a new way for CreateControlFlowHub() 
The existing way of creating the predicate in the guard blocks uses
a boolean value per outgoing block. This increases the number of live
booleans as the number of outgoing blocks increases. The new way added
in this change is to store one integer to represent the outgoing block
we want to branch to, then at each guard block, an integer equality
check is performed to decide which a specific outgoing block is taken.

Using an integer reduces the number of live values and decreases
register pressure especially in cases where there are a large number
of outgoing blocks. The integer based approach is used when the
number of outgoing blocks crosses a threshold, which is currently set
to 32.

Patch by Ruiling Song.

Differential review: https://reviews.llvm.org/D127831
2022-10-31 08:58:54 -05:00

349 lines
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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -passes=unify-loop-exits -max-booleans-in-control-flow-hub=1 -S | FileCheck %s
; RUN: opt < %s -passes=unify-loop-exits -S | FileCheck --check-prefix=BOOLEAN %s
; A loop with multiple exit blocks.
define void @loop_two_exits(i1 %PredEntry, i1 %PredA) {
; CHECK-LABEL: @loop_two_exits(
; CHECK-NEXT: entry:
; CHECK-NEXT: br i1 [[PREDENTRY:%.*]], label [[A:%.*]], label [[E:%.*]]
; CHECK: A:
; CHECK-NEXT: [[INC1:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[INC2:%.*]], [[C:%.*]] ]
; CHECK-NEXT: br i1 [[PREDA:%.*]], label [[LOOP_EXIT_GUARD:%.*]], label [[C]]
; CHECK: B:
; CHECK-NEXT: tail call fastcc void @check(i32 1) #[[ATTR0:[0-9]+]]
; CHECK-NEXT: br label [[D:%.*]]
; CHECK: C:
; CHECK-NEXT: [[INC2]] = add i32 [[INC1]], 1
; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[INC2]], 10
; CHECK-NEXT: br i1 [[CMP]], label [[A]], label [[LOOP_EXIT_GUARD]]
; CHECK: D:
; CHECK-NEXT: unreachable
; CHECK: E:
; CHECK-NEXT: ret void
; CHECK: loop.exit.guard:
; CHECK-NEXT: [[MERGED_BB_IDX:%.*]] = phi i32 [ 0, [[A]] ], [ 1, [[C]] ]
; CHECK-NEXT: [[B_PREDICATE:%.*]] = icmp eq i32 [[MERGED_BB_IDX]], 0
; CHECK-NEXT: br i1 [[B_PREDICATE]], label [[B:%.*]], label [[E]]
;
; BOOLEAN-LABEL: @loop_two_exits(
; BOOLEAN-NEXT: entry:
; BOOLEAN-NEXT: br i1 [[PREDENTRY:%.*]], label [[A:%.*]], label [[E:%.*]]
; BOOLEAN: A:
; BOOLEAN-NEXT: [[INC1:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[INC2:%.*]], [[C:%.*]] ]
; BOOLEAN-NEXT: br i1 [[PREDA:%.*]], label [[LOOP_EXIT_GUARD:%.*]], label [[C]]
; BOOLEAN: B:
; BOOLEAN-NEXT: tail call fastcc void @check(i32 1) #[[ATTR0:[0-9]+]]
; BOOLEAN-NEXT: br label [[D:%.*]]
; BOOLEAN: C:
; BOOLEAN-NEXT: [[INC2]] = add i32 [[INC1]], 1
; BOOLEAN-NEXT: [[CMP:%.*]] = icmp ult i32 [[INC2]], 10
; BOOLEAN-NEXT: br i1 [[CMP]], label [[A]], label [[LOOP_EXIT_GUARD]]
; BOOLEAN: D:
; BOOLEAN-NEXT: unreachable
; BOOLEAN: E:
; BOOLEAN-NEXT: ret void
; BOOLEAN: loop.exit.guard:
; BOOLEAN-NEXT: [[GUARD_B:%.*]] = phi i1 [ true, [[A]] ], [ false, [[C]] ]
; BOOLEAN-NEXT: br i1 [[GUARD_B]], label [[B:%.*]], label [[E]]
;
entry:
br i1 %PredEntry, label %A, label %E
A:
%inc1 = phi i32 [ 0, %entry ], [ %inc2, %C ]
br i1 %PredA, label %B, label %C
B:
tail call fastcc void @check(i32 1) #0
br label %D
C:
%inc2 = add i32 %inc1, 1
%cmp = icmp ult i32 %inc2, 10
br i1 %cmp, label %A, label %E
D:
unreachable
E:
ret void
}
; The loop exit blocks appear in an inner loop.
define void @inner_loop(i1 %PredEntry, i1 %PredA, i1 %PredB) {
; CHECK-LABEL: @inner_loop(
; CHECK-NEXT: entry:
; CHECK-NEXT: br i1 [[PREDENTRY:%.*]], label [[A:%.*]], label [[I:%.*]]
; CHECK: A:
; CHECK-NEXT: [[OUTER1:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[OUTER2:%.*]], [[G:%.*]] ]
; CHECK-NEXT: br label [[B:%.*]]
; CHECK: B:
; CHECK-NEXT: [[INNER1:%.*]] = phi i32 [ 0, [[A]] ], [ [[INNER2:%.*]], [[F:%.*]] ]
; CHECK-NEXT: br i1 [[PREDA:%.*]], label [[D:%.*]], label [[LOOP_EXIT_GUARD2:%.*]]
; CHECK: C:
; CHECK-NEXT: tail call fastcc void @check(i32 1) #[[ATTR0]]
; CHECK-NEXT: br label [[H:%.*]]
; CHECK: D:
; CHECK-NEXT: br i1 [[PREDB:%.*]], label [[LOOP_EXIT_GUARD2]], label [[F]]
; CHECK: E:
; CHECK-NEXT: tail call fastcc void @check(i32 2) #[[ATTR0]]
; CHECK-NEXT: br label [[H]]
; CHECK: F:
; CHECK-NEXT: [[INNER2]] = add i32 [[INNER1]], 1
; CHECK-NEXT: [[CMP1:%.*]] = icmp ult i32 [[INNER2]], 20
; CHECK-NEXT: br i1 [[CMP1]], label [[B]], label [[LOOP_EXIT_GUARD2]]
; CHECK: G:
; CHECK-NEXT: [[OUTER2]] = add i32 [[OUTER1]], 1
; CHECK-NEXT: [[CMP2:%.*]] = icmp ult i32 [[OUTER2]], 10
; CHECK-NEXT: br i1 [[CMP2]], label [[A]], label [[LOOP_EXIT_GUARD:%.*]]
; CHECK: H:
; CHECK-NEXT: unreachable
; CHECK: I:
; CHECK-NEXT: ret void
; CHECK: loop.exit.guard:
; CHECK-NEXT: [[MERGED_BB_IDX:%.*]] = phi i32 [ 2, [[G]] ], [ [[MERGED_BB_IDX_MOVED:%.*]], [[LOOP_EXIT_GUARD2]] ]
; CHECK-NEXT: [[C_PREDICATE:%.*]] = icmp eq i32 [[MERGED_BB_IDX]], 0
; CHECK-NEXT: br i1 [[C_PREDICATE]], label [[C:%.*]], label [[LOOP_EXIT_GUARD1:%.*]]
; CHECK: loop.exit.guard1:
; CHECK-NEXT: [[E_PREDICATE:%.*]] = icmp eq i32 [[MERGED_BB_IDX]], 1
; CHECK-NEXT: br i1 [[E_PREDICATE]], label [[E:%.*]], label [[I]]
; CHECK: loop.exit.guard2:
; CHECK-NEXT: [[MERGED_BB_IDX_MOVED]] = phi i32 [ 0, [[B]] ], [ 1, [[D]] ], [ undef, [[F]] ]
; CHECK-NEXT: [[MERGED_BB_IDX3:%.*]] = phi i32 [ 0, [[B]] ], [ 0, [[D]] ], [ 1, [[F]] ]
; CHECK-NEXT: [[LOOP_EXIT_GUARD_PREDICATE:%.*]] = icmp eq i32 [[MERGED_BB_IDX3]], 0
; CHECK-NEXT: br i1 [[LOOP_EXIT_GUARD_PREDICATE]], label [[LOOP_EXIT_GUARD]], label [[G]]
;
; BOOLEAN-LABEL: @inner_loop(
; BOOLEAN-NEXT: entry:
; BOOLEAN-NEXT: br i1 [[PREDENTRY:%.*]], label [[A:%.*]], label [[I:%.*]]
; BOOLEAN: A:
; BOOLEAN-NEXT: [[OUTER1:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[OUTER2:%.*]], [[G:%.*]] ]
; BOOLEAN-NEXT: br label [[B:%.*]]
; BOOLEAN: B:
; BOOLEAN-NEXT: [[INNER1:%.*]] = phi i32 [ 0, [[A]] ], [ [[INNER2:%.*]], [[F:%.*]] ]
; BOOLEAN-NEXT: br i1 [[PREDA:%.*]], label [[D:%.*]], label [[LOOP_EXIT_GUARD2:%.*]]
; BOOLEAN: C:
; BOOLEAN-NEXT: tail call fastcc void @check(i32 1) #[[ATTR0]]
; BOOLEAN-NEXT: br label [[H:%.*]]
; BOOLEAN: D:
; BOOLEAN-NEXT: br i1 [[PREDB:%.*]], label [[LOOP_EXIT_GUARD2]], label [[F]]
; BOOLEAN: E:
; BOOLEAN-NEXT: tail call fastcc void @check(i32 2) #[[ATTR0]]
; BOOLEAN-NEXT: br label [[H]]
; BOOLEAN: F:
; BOOLEAN-NEXT: [[INNER2]] = add i32 [[INNER1]], 1
; BOOLEAN-NEXT: [[CMP1:%.*]] = icmp ult i32 [[INNER2]], 20
; BOOLEAN-NEXT: br i1 [[CMP1]], label [[B]], label [[LOOP_EXIT_GUARD2]]
; BOOLEAN: G:
; BOOLEAN-NEXT: [[OUTER2]] = add i32 [[OUTER1]], 1
; BOOLEAN-NEXT: [[CMP2:%.*]] = icmp ult i32 [[OUTER2]], 10
; BOOLEAN-NEXT: br i1 [[CMP2]], label [[A]], label [[LOOP_EXIT_GUARD:%.*]]
; BOOLEAN: H:
; BOOLEAN-NEXT: unreachable
; BOOLEAN: I:
; BOOLEAN-NEXT: ret void
; BOOLEAN: loop.exit.guard:
; BOOLEAN-NEXT: [[GUARD_C:%.*]] = phi i1 [ false, [[G]] ], [ [[GUARD_C_MOVED:%.*]], [[LOOP_EXIT_GUARD2]] ]
; BOOLEAN-NEXT: [[GUARD_E:%.*]] = phi i1 [ false, [[G]] ], [ [[GUARD_E_MOVED:%.*]], [[LOOP_EXIT_GUARD2]] ]
; BOOLEAN-NEXT: br i1 [[GUARD_C]], label [[C:%.*]], label [[LOOP_EXIT_GUARD1:%.*]]
; BOOLEAN: loop.exit.guard1:
; BOOLEAN-NEXT: br i1 [[GUARD_E]], label [[E:%.*]], label [[I]]
; BOOLEAN: loop.exit.guard2:
; BOOLEAN-NEXT: [[GUARD_E_MOVED]] = phi i1 [ false, [[B]] ], [ true, [[D]] ], [ undef, [[F]] ]
; BOOLEAN-NEXT: [[GUARD_C_MOVED]] = phi i1 [ true, [[B]] ], [ false, [[D]] ], [ undef, [[F]] ]
; BOOLEAN-NEXT: [[GUARD_LOOP_EXIT_GUARD:%.*]] = phi i1 [ true, [[B]] ], [ true, [[D]] ], [ false, [[F]] ]
; BOOLEAN-NEXT: br i1 [[GUARD_LOOP_EXIT_GUARD]], label [[LOOP_EXIT_GUARD]], label [[G]]
;
entry:
br i1 %PredEntry, label %A, label %I
A:
%outer1 = phi i32 [ 0, %entry ], [ %outer2, %G ]
br label %B
B:
%inner1 = phi i32 [ 0, %A ], [ %inner2, %F ]
br i1 %PredA, label %D, label %C
C:
tail call fastcc void @check(i32 1) #0
br label %H
D:
br i1 %PredB, label %E, label %F
E:
tail call fastcc void @check(i32 2) #0
br label %H
F:
%inner2 = add i32 %inner1, 1
%cmp1 = icmp ult i32 %inner2, 20
br i1 %cmp1, label %B, label %G
G:
%outer2 = add i32 %outer1, 1
%cmp2 = icmp ult i32 %outer2, 10
br i1 %cmp2, label %A, label %I
H:
unreachable
I:
ret void
}
; A loop with more exit blocks.
define void @loop_five_exits(i1 %PredEntry, i1 %PredA, i1 %PredB, i1 %PredC, i1 %PredD) {
; CHECK-LABEL: @loop_five_exits(
; CHECK-NEXT: entry:
; CHECK-NEXT: br i1 [[PREDENTRY:%.*]], label [[A:%.*]], label [[L:%.*]]
; CHECK: A:
; CHECK-NEXT: [[INC1:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[INC2:%.*]], [[I:%.*]] ]
; CHECK-NEXT: br i1 [[PREDA:%.*]], label [[LOOP_EXIT_GUARD:%.*]], label [[C:%.*]]
; CHECK: B:
; CHECK-NEXT: tail call fastcc void @check(i32 1) #[[ATTR0]]
; CHECK-NEXT: br label [[J:%.*]]
; CHECK: C:
; CHECK-NEXT: br i1 [[PREDB:%.*]], label [[LOOP_EXIT_GUARD]], label [[E:%.*]]
; CHECK: D:
; CHECK-NEXT: tail call fastcc void @check(i32 2) #[[ATTR0]]
; CHECK-NEXT: br label [[J]]
; CHECK: E:
; CHECK-NEXT: br i1 [[PREDC:%.*]], label [[LOOP_EXIT_GUARD]], label [[G:%.*]]
; CHECK: F:
; CHECK-NEXT: tail call fastcc void @check(i32 3) #[[ATTR0]]
; CHECK-NEXT: br label [[K:%.*]]
; CHECK: G:
; CHECK-NEXT: br i1 [[PREDD:%.*]], label [[LOOP_EXIT_GUARD]], label [[I]]
; CHECK: H:
; CHECK-NEXT: tail call fastcc void @check(i32 4) #[[ATTR0]]
; CHECK-NEXT: br label [[K]]
; CHECK: I:
; CHECK-NEXT: [[INC2]] = add i32 [[INC1]], 1
; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[INC2]], 10
; CHECK-NEXT: br i1 [[CMP]], label [[A]], label [[LOOP_EXIT_GUARD]]
; CHECK: J:
; CHECK-NEXT: br label [[L]]
; CHECK: K:
; CHECK-NEXT: br label [[L]]
; CHECK: L:
; CHECK-NEXT: ret void
; CHECK: loop.exit.guard:
; CHECK-NEXT: [[MERGED_BB_IDX:%.*]] = phi i32 [ 0, [[A]] ], [ 1, [[C]] ], [ 2, [[E]] ], [ 3, [[G]] ], [ 4, [[I]] ]
; CHECK-NEXT: [[B_PREDICATE:%.*]] = icmp eq i32 [[MERGED_BB_IDX]], 0
; CHECK-NEXT: br i1 [[B_PREDICATE]], label [[B:%.*]], label [[LOOP_EXIT_GUARD1:%.*]]
; CHECK: loop.exit.guard1:
; CHECK-NEXT: [[D_PREDICATE:%.*]] = icmp eq i32 [[MERGED_BB_IDX]], 1
; CHECK-NEXT: br i1 [[D_PREDICATE]], label [[D:%.*]], label [[LOOP_EXIT_GUARD2:%.*]]
; CHECK: loop.exit.guard2:
; CHECK-NEXT: [[F_PREDICATE:%.*]] = icmp eq i32 [[MERGED_BB_IDX]], 2
; CHECK-NEXT: br i1 [[F_PREDICATE]], label [[F:%.*]], label [[LOOP_EXIT_GUARD3:%.*]]
; CHECK: loop.exit.guard3:
; CHECK-NEXT: [[H_PREDICATE:%.*]] = icmp eq i32 [[MERGED_BB_IDX]], 3
; CHECK-NEXT: br i1 [[H_PREDICATE]], label [[H:%.*]], label [[L]]
;
; BOOLEAN-LABEL: @loop_five_exits(
; BOOLEAN-NEXT: entry:
; BOOLEAN-NEXT: br i1 [[PREDENTRY:%.*]], label [[A:%.*]], label [[L:%.*]]
; BOOLEAN: A:
; BOOLEAN-NEXT: [[INC1:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[INC2:%.*]], [[I:%.*]] ]
; BOOLEAN-NEXT: br i1 [[PREDA:%.*]], label [[LOOP_EXIT_GUARD:%.*]], label [[C:%.*]]
; BOOLEAN: B:
; BOOLEAN-NEXT: tail call fastcc void @check(i32 1) #[[ATTR0]]
; BOOLEAN-NEXT: br label [[J:%.*]]
; BOOLEAN: C:
; BOOLEAN-NEXT: br i1 [[PREDB:%.*]], label [[LOOP_EXIT_GUARD]], label [[E:%.*]]
; BOOLEAN: D:
; BOOLEAN-NEXT: tail call fastcc void @check(i32 2) #[[ATTR0]]
; BOOLEAN-NEXT: br label [[J]]
; BOOLEAN: E:
; BOOLEAN-NEXT: br i1 [[PREDC:%.*]], label [[LOOP_EXIT_GUARD]], label [[G:%.*]]
; BOOLEAN: F:
; BOOLEAN-NEXT: tail call fastcc void @check(i32 3) #[[ATTR0]]
; BOOLEAN-NEXT: br label [[K:%.*]]
; BOOLEAN: G:
; BOOLEAN-NEXT: br i1 [[PREDD:%.*]], label [[LOOP_EXIT_GUARD]], label [[I]]
; BOOLEAN: H:
; BOOLEAN-NEXT: tail call fastcc void @check(i32 4) #[[ATTR0]]
; BOOLEAN-NEXT: br label [[K]]
; BOOLEAN: I:
; BOOLEAN-NEXT: [[INC2]] = add i32 [[INC1]], 1
; BOOLEAN-NEXT: [[CMP:%.*]] = icmp ult i32 [[INC2]], 10
; BOOLEAN-NEXT: br i1 [[CMP]], label [[A]], label [[LOOP_EXIT_GUARD]]
; BOOLEAN: J:
; BOOLEAN-NEXT: br label [[L]]
; BOOLEAN: K:
; BOOLEAN-NEXT: br label [[L]]
; BOOLEAN: L:
; BOOLEAN-NEXT: ret void
; BOOLEAN: loop.exit.guard:
; BOOLEAN-NEXT: [[GUARD_B:%.*]] = phi i1 [ true, [[A]] ], [ false, [[C]] ], [ false, [[E]] ], [ false, [[G]] ], [ false, [[I]] ]
; BOOLEAN-NEXT: [[GUARD_D:%.*]] = phi i1 [ false, [[A]] ], [ true, [[C]] ], [ false, [[E]] ], [ false, [[G]] ], [ false, [[I]] ]
; BOOLEAN-NEXT: [[GUARD_F:%.*]] = phi i1 [ false, [[A]] ], [ false, [[C]] ], [ true, [[E]] ], [ false, [[G]] ], [ false, [[I]] ]
; BOOLEAN-NEXT: [[GUARD_H:%.*]] = phi i1 [ false, [[A]] ], [ false, [[C]] ], [ false, [[E]] ], [ true, [[G]] ], [ false, [[I]] ]
; BOOLEAN-NEXT: br i1 [[GUARD_B]], label [[B:%.*]], label [[LOOP_EXIT_GUARD1:%.*]]
; BOOLEAN: loop.exit.guard1:
; BOOLEAN-NEXT: br i1 [[GUARD_D]], label [[D:%.*]], label [[LOOP_EXIT_GUARD2:%.*]]
; BOOLEAN: loop.exit.guard2:
; BOOLEAN-NEXT: br i1 [[GUARD_F]], label [[F:%.*]], label [[LOOP_EXIT_GUARD3:%.*]]
; BOOLEAN: loop.exit.guard3:
; BOOLEAN-NEXT: br i1 [[GUARD_H]], label [[H:%.*]], label [[L]]
;
entry:
br i1 %PredEntry, label %A, label %L
A:
%inc1 = phi i32 [ 0, %entry ], [ %inc2, %I ]
br i1 %PredA, label %B, label %C
B:
tail call fastcc void @check(i32 1) #0
br label %J
C:
br i1 %PredB, label %D, label %E
D:
tail call fastcc void @check(i32 2) #0
br label %J
E:
br i1 %PredC, label %F, label %G
F:
tail call fastcc void @check(i32 3) #0
br label %K
G:
br i1 %PredD, label %H, label %I
H:
tail call fastcc void @check(i32 4) #0
br label %K
I:
%inc2 = add i32 %inc1, 1
%cmp = icmp ult i32 %inc2, 10
br i1 %cmp, label %A, label %L
J:
br label %L
K:
br label %L
L:
ret void
}
declare void @check(i32 noundef %i) #0
attributes #0 = { noreturn nounwind }
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