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clang-p2996/llvm/test/Transforms/LoopPredication/profitability.ll
Dmitry Makogon 8307f6c854 [LoopPredication] Insert assumes of conditions of predicated guards 
As LoopPredication performs non-equivalent transforms removing some
checks from loops, other passes may not be able to perform transforms
they'd be able to do if the checks were left in loops.

This patch makes LoopPredication insert assumes of the replaced
conditions either after a guard call or in the true block of
widenable condition branch.

Differential Revision: https://reviews.llvm.org/D135354
2022-10-07 16:10:24 +07:00

180 lines
9.1 KiB
LLVM
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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -S -loop-predication-skip-profitability-checks=false -passes='require<scalar-evolution>,loop-mssa(loop-predication)' -verify-memoryssa < %s 2>&1 | FileCheck %s
; latch block exits to a speculation block. We account for this since deopt is
; very rarely taken. So we do not predicate this loop using that coarse latch
; check.
; LatchExitProbability: 0x04000000 / 0x80000000 = 3.12%
; ExitingBlockProbability: 0x7ffa572a / 0x80000000 = 99.98%
define i64 @donot_predicate(i64* nocapture readonly %arg, i32 %length, i64* nocapture readonly %arg2, i64* nocapture readonly %n_addr, i64 %i) !prof !21 {
; CHECK-LABEL: @donot_predicate(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[LENGTH_EXT:%.*]] = zext i32 [[LENGTH:%.*]] to i64
; CHECK-NEXT: [[N_PRE:%.*]] = load i64, i64* [[N_ADDR:%.*]], align 4
; CHECK-NEXT: br label [[HEADER:%.*]]
; CHECK: Header:
; CHECK-NEXT: [[RESULT_IN3:%.*]] = phi i64* [ [[ARG2:%.*]], [[ENTRY:%.*]] ], [ [[ARG:%.*]], [[LATCH:%.*]] ]
; CHECK-NEXT: [[J2:%.*]] = phi i64 [ 0, [[ENTRY]] ], [ [[J_NEXT:%.*]], [[LATCH]] ]
; CHECK-NEXT: [[WITHIN_BOUNDS:%.*]] = icmp ult i64 [[J2]], [[LENGTH_EXT]]
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 [[WITHIN_BOUNDS]], i32 9) [ "deopt"() ]
; CHECK-NEXT: [[INNERCMP:%.*]] = icmp eq i64 [[J2]], [[N_PRE]]
; CHECK-NEXT: [[J_NEXT]] = add nuw nsw i64 [[J2]], 1
; CHECK-NEXT: br i1 [[INNERCMP]], label [[LATCH]], label [[EXIT:%.*]], !prof [[PROF1:![0-9]+]]
; CHECK: Latch:
; CHECK-NEXT: [[SPECULATE_TRIP_COUNT:%.*]] = icmp ult i64 [[J_NEXT]], 1048576
; CHECK-NEXT: br i1 [[SPECULATE_TRIP_COUNT]], label [[HEADER]], label [[DEOPT:%.*]]
; CHECK: deopt:
; CHECK-NEXT: [[COUNTED_SPECULATION_FAILED:%.*]] = call i64 (...) @llvm.experimental.deoptimize.i64(i64 30) [ "deopt"(i32 0) ]
; CHECK-NEXT: ret i64 [[COUNTED_SPECULATION_FAILED]]
; CHECK: exit:
; CHECK-NEXT: [[RESULT_IN3_LCSSA:%.*]] = phi i64* [ [[RESULT_IN3]], [[HEADER]] ]
; CHECK-NEXT: [[RESULT_LE:%.*]] = load i64, i64* [[RESULT_IN3_LCSSA]], align 8
; CHECK-NEXT: ret i64 [[RESULT_LE]]
;
entry:
%length.ext = zext i32 %length to i64
%n.pre = load i64, i64* %n_addr, align 4
br label %Header
Header: ; preds = %entry, %Latch
%result.in3 = phi i64* [ %arg2, %entry ], [ %arg, %Latch ]
%j2 = phi i64 [ 0, %entry ], [ %j.next, %Latch ]
%within.bounds = icmp ult i64 %j2, %length.ext
call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ]
%innercmp = icmp eq i64 %j2, %n.pre
%j.next = add nuw nsw i64 %j2, 1
br i1 %innercmp, label %Latch, label %exit, !prof !0
Latch: ; preds = %Header
%speculate_trip_count = icmp ult i64 %j.next, 1048576
br i1 %speculate_trip_count, label %Header, label %deopt
deopt: ; preds = %Latch
%counted_speculation_failed = call i64 (...) @llvm.experimental.deoptimize.i64(i64 30) [ "deopt"(i32 0) ]
ret i64 %counted_speculation_failed
exit: ; preds = %Header
%result.in3.lcssa = phi i64* [ %result.in3, %Header ]
%result.le = load i64, i64* %result.in3.lcssa, align 8
ret i64 %result.le
}
!0 = !{!"branch_weights", i32 18, i32 104200}
; predicate loop since there's no profile information and BPI concluded all
; exiting blocks have same probability of exiting from loop.
define i64 @predicate(i64* nocapture readonly %arg, i32 %length, i64* nocapture readonly %arg2, i64* nocapture readonly %n_addr, i64 %i) !prof !21 {
; CHECK-LABEL: @predicate(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[LENGTH_EXT:%.*]] = zext i32 [[LENGTH:%.*]] to i64
; CHECK-NEXT: [[N_PRE:%.*]] = load i64, i64* [[N_ADDR:%.*]], align 4
; CHECK-NEXT: [[TMP0:%.*]] = icmp ule i64 1048576, [[LENGTH_EXT]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i64 0, [[LENGTH_EXT]]
; CHECK-NEXT: [[TMP2:%.*]] = and i1 [[TMP1]], [[TMP0]]
; CHECK-NEXT: br label [[HEADER:%.*]]
; CHECK: Header:
; CHECK-NEXT: [[RESULT_IN3:%.*]] = phi i64* [ [[ARG2:%.*]], [[ENTRY:%.*]] ], [ [[ARG:%.*]], [[LATCH:%.*]] ]
; CHECK-NEXT: [[J2:%.*]] = phi i64 [ 0, [[ENTRY]] ], [ [[J_NEXT:%.*]], [[LATCH]] ]
; CHECK-NEXT: [[WITHIN_BOUNDS:%.*]] = icmp ult i64 [[J2]], [[LENGTH_EXT]]
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 [[TMP2]], i32 9) [ "deopt"() ]
; CHECK-NEXT: call void @llvm.assume(i1 [[WITHIN_BOUNDS]])
; CHECK-NEXT: [[INNERCMP:%.*]] = icmp eq i64 [[J2]], [[N_PRE]]
; CHECK-NEXT: [[J_NEXT]] = add nuw nsw i64 [[J2]], 1
; CHECK-NEXT: br i1 [[INNERCMP]], label [[LATCH]], label [[EXIT:%.*]]
; CHECK: Latch:
; CHECK-NEXT: [[SPECULATE_TRIP_COUNT:%.*]] = icmp ult i64 [[J_NEXT]], 1048576
; CHECK-NEXT: br i1 [[SPECULATE_TRIP_COUNT]], label [[HEADER]], label [[EXITLATCH:%.*]]
; CHECK: exitLatch:
; CHECK-NEXT: ret i64 1
; CHECK: exit:
; CHECK-NEXT: [[RESULT_IN3_LCSSA:%.*]] = phi i64* [ [[RESULT_IN3]], [[HEADER]] ]
; CHECK-NEXT: [[RESULT_LE:%.*]] = load i64, i64* [[RESULT_IN3_LCSSA]], align 8
; CHECK-NEXT: ret i64 [[RESULT_LE]]
;
entry:
%length.ext = zext i32 %length to i64
%n.pre = load i64, i64* %n_addr, align 4
br label %Header
Header: ; preds = %entry, %Latch
%result.in3 = phi i64* [ %arg2, %entry ], [ %arg, %Latch ]
%j2 = phi i64 [ 0, %entry ], [ %j.next, %Latch ]
%within.bounds = icmp ult i64 %j2, %length.ext
call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ]
%innercmp = icmp eq i64 %j2, %n.pre
%j.next = add nuw nsw i64 %j2, 1
br i1 %innercmp, label %Latch, label %exit
Latch: ; preds = %Header
%speculate_trip_count = icmp ult i64 %j.next, 1048576
br i1 %speculate_trip_count, label %Header, label %exitLatch
exitLatch: ; preds = %Latch
ret i64 1
exit: ; preds = %Header
%result.in3.lcssa = phi i64* [ %result.in3, %Header ]
%result.le = load i64, i64* %result.in3.lcssa, align 8
ret i64 %result.le
}
; Same as test above but with profiling data that the most probable exit from
; the loop is the header exiting block (not the latch block). So do not predicate.
; LatchExitProbability: 0x000020e1 / 0x80000000 = 0.00%
; ExitingBlockProbability: 0x7ffcbb86 / 0x80000000 = 99.99%
define i64 @donot_predicate_prof(i64* nocapture readonly %arg, i32 %length, i64* nocapture readonly %arg2, i64* nocapture readonly %n_addr, i64 %i) !prof !21 {
; CHECK-LABEL: @donot_predicate_prof(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[LENGTH_EXT:%.*]] = zext i32 [[LENGTH:%.*]] to i64
; CHECK-NEXT: [[N_PRE:%.*]] = load i64, i64* [[N_ADDR:%.*]], align 4
; CHECK-NEXT: br label [[HEADER:%.*]]
; CHECK: Header:
; CHECK-NEXT: [[RESULT_IN3:%.*]] = phi i64* [ [[ARG2:%.*]], [[ENTRY:%.*]] ], [ [[ARG:%.*]], [[LATCH:%.*]] ]
; CHECK-NEXT: [[J2:%.*]] = phi i64 [ 0, [[ENTRY]] ], [ [[J_NEXT:%.*]], [[LATCH]] ]
; CHECK-NEXT: [[WITHIN_BOUNDS:%.*]] = icmp ult i64 [[J2]], [[LENGTH_EXT]]
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 [[WITHIN_BOUNDS]], i32 9) [ "deopt"() ]
; CHECK-NEXT: [[INNERCMP:%.*]] = icmp eq i64 [[J2]], [[N_PRE]]
; CHECK-NEXT: [[J_NEXT]] = add nuw nsw i64 [[J2]], 1
; CHECK-NEXT: br i1 [[INNERCMP]], label [[LATCH]], label [[EXIT:%.*]], !prof [[PROF2:![0-9]+]]
; CHECK: Latch:
; CHECK-NEXT: [[SPECULATE_TRIP_COUNT:%.*]] = icmp ult i64 [[J_NEXT]], 1048576
; CHECK-NEXT: br i1 [[SPECULATE_TRIP_COUNT]], label [[HEADER]], label [[EXITLATCH:%.*]], !prof [[PROF3:![0-9]+]]
; CHECK: exitLatch:
; CHECK-NEXT: ret i64 1
; CHECK: exit:
; CHECK-NEXT: [[RESULT_IN3_LCSSA:%.*]] = phi i64* [ [[RESULT_IN3]], [[HEADER]] ]
; CHECK-NEXT: [[RESULT_LE:%.*]] = load i64, i64* [[RESULT_IN3_LCSSA]], align 8
; CHECK-NEXT: ret i64 [[RESULT_LE]]
;
entry:
%length.ext = zext i32 %length to i64
%n.pre = load i64, i64* %n_addr, align 4
br label %Header
Header: ; preds = %entry, %Latch
%result.in3 = phi i64* [ %arg2, %entry ], [ %arg, %Latch ]
%j2 = phi i64 [ 0, %entry ], [ %j.next, %Latch ]
%within.bounds = icmp ult i64 %j2, %length.ext
call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ]
%innercmp = icmp eq i64 %j2, %n.pre
%j.next = add nuw nsw i64 %j2, 1
br i1 %innercmp, label %Latch, label %exit, !prof !1
Latch: ; preds = %Header
%speculate_trip_count = icmp ult i64 %j.next, 1048576
br i1 %speculate_trip_count, label %Header, label %exitLatch, !prof !2
exitLatch: ; preds = %Latch
ret i64 1
exit: ; preds = %Header
%result.in3.lcssa = phi i64* [ %result.in3, %Header ]
%result.le = load i64, i64* %result.in3.lcssa, align 8
ret i64 %result.le
}
declare i64 @llvm.experimental.deoptimize.i64(...)
declare void @llvm.experimental.guard(i1, ...)
!1 = !{!"branch_weights", i32 104, i32 1042861}
!2 = !{!"branch_weights", i32 255129, i32 1}
!21 = !{!"function_entry_count", i64 20000}
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